This file documents Texinfo, a documentation system that can produce both on-line information and a printed manual from a single source file.

Copyright (C) 1988, 90, 91, 92, 93, 95, 96, 97 Free Software Foundation, Inc.

This is the second edition of the Texinfo documentation,

and is consistent with version 2 of texinfo.tex.

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Free Software Foundation.

Texinfo
*******

Texinfo is a documentation system that uses a single source file to produce both on-line information and printed output.

The first part of this master menu lists the major nodes in this Info document, including the @-command and concept indices.  The rest of the menu lists all the lower level nodes in the document.

This is Edition 2.24 of the Texinfo documentation, 15 July 1997, for Texinfo Version Three.

Texinfo Copying Conditions
**************************

The programs currently being distributed that relate to Texinfo include portions of GNU Emacs, plus other separate programs (including makeinfo, info, texindex, and texinfo.tex). These programs are free; this means that everyone is free to use them and free to redistribute them on a free basis.  The Texinfo-related programs are not in the public domain; they are copyrighted and there are restrictions on their distribution, but these restrictions are designed to permit everything that a good cooperating citizen would want to do.  What is not allowed is to try to prevent others from further sharing any version of these programs that they might get from you.

Specifically, we want to make sure that you have the right to give away copies of the programs that relate to Texinfo, that you receive source code or else can get it if you want it, that you can change these programs or use pieces of them in new free programs, and that you know you can do these things.

To make sure that everyone has such rights, we have to forbid you to deprive anyone else of these rights.  For example, if you distribute copies of the Texinfo related programs, you must give the recipients all the rights that you have.  You must make sure that they, too, receive or can get the source code.  And you must tell them their rights.

Also, for our own protection, we must make certain that everyone finds out that there is no warranty for the programs that relate to Texinfo. If these programs are modified by someone else and passed on, we want their recipients to know that what they have is not what we distributed, so that any problems introduced by others will not reflect on our reputation.

The precise conditions of the licenses for the programs currently being distributed that relate to Texinfo are found in the General Public Licenses that accompany them.

Overview of Texinfo
*******************

Texinfo (Note that the first syllable of ``Texinfo'' is pronounced like ``speck'', not ``hex''.  This odd pronunciation is derived from, but is not the same as, the pronunciation of TeX.  In the word TeX, the X is actually the Greek letter ``chi'' rather than the English letter ``ex''.  Pronounce TeX as if the X were the last sound in the name `Bach'; but pronounce Texinfo as if the x were a `k'.  Spell ``Texinfo'' with a capital ``T'' and write the other letters in lower case.) is a documentation system that uses a single source file to produce both on-line information and printed output.  This means that instead of writing two different documents, one for the on-line help or other on-line information and the other for a typeset manual or other printed work, you need write only one document.  When the work is revised, you need revise only one document.  (You can read the on-line information, known as an Info file, with an Info documentation-reading program.)

Using Texinfo
=============

Using Texinfo, you can create a printed document with the normal features of a book, including chapters, sections, cross references, and indices.  From the same Texinfo source file, you can create a menu-driven, on-line Info file with nodes, menus, cross references, and indices.  You can, if you wish, make the chapters and sections of the printed document correspond to the nodes of the on-line information; and you use the same cross references and indices for both the Info file and the printed work.  The GNU Emacs Manual is a good example of a Texinfo file, as is this manual.

To make a printed document, you process a Texinfo source file with the TeX typesetting program.  This creates a DVI file that you can typeset and print as a book or report.  (Note that the Texinfo language is completely different from TeX's usual language, plain TeX.)  If you do not have TeX, but do have troff or nroff, you can use the texi2roff program instead.

To make an Info file, you process a Texinfo source file with the makeinfo utility or Emacs's texinfo-format-buffer command; this creates an Info file that you can install on-line.

TeX and texi2roff work with many types of printers; similarly, Info works with almost every type of computer terminal.  This power makes Texinfo a general purpose system, but brings with it a constraint, which is that a Texinfo file may contain only the customary ``typewriter'' characters (letters, numbers, spaces, and punctuation marks) but no special graphics.

A Texinfo file is a plain ASCII file containing text and @-commands (words preceded by an @) that tell the typesetting and formatting programs what to do.  You may edit a Texinfo file with any text editor; but it is especially convenient to use GNU Emacs since that editor has a special mode, called Texinfo mode, that provides various Texinfo-related features.  (see Texinfo Mode.)

Before writing a Texinfo source file, you should become familiar with the Info documentation reading program and learn about nodes, menus, cross references, and the rest.  (see info, for more information.)

You can use Texinfo to create both on-line help and printed manuals; moreover, Texinfo is freely redistributable.  For these reasons, Texinfo is the format in which documentation for GNU utilities and libraries is written.

Info files
==========

An Info file is a Texinfo file formatted so that the Info documentation reading program can operate on it.  (makeinfo and texinfo-format-buffer are two commands that convert a Texinfo file into an Info file.)

Info files are divided into pieces called nodes, each of which contains the discussion of one topic.  Each node has a name, and contains both text for the user to read and pointers to other nodes, which are identified by their names.  The Info program displays one node at a time, and provides commands with which the user can move to other related nodes.

See info, for more information about using Info.

Each node of an Info file may have any number of child nodes that describe subtopics of the node's topic.  The names of child nodes are listed in a menu within the parent node; this allows you to use certain Info commands to move to one of the child nodes.  Generally, an Info file is organized like a book.  If a node is at the logical level of a chapter, its child nodes are at the level of sections; likewise, the child nodes of sections are at the level of subsections.

All the children of any one parent are linked together in a bidirectional chain of `Next' and `Previous' pointers.  The `Next' pointer provides a link to the next section, and the `Previous' pointer provides a link to the previous section.  This means that all the nodes that are at the level of sections within a chapter are linked together. Normally the order in this chain is the same as the order of the children in the parent's menu.  Each child node records the parent node name as its `Up' pointer.  The last child has no `Next' pointer, and the first child has the parent both as its `Previous' and as its `Up' pointer. (In some documents, the first child has no `Previous' pointer.  Occasionally, the last child has the node name of the next following higher level node as its `Next' pointer.)

The book-like structuring of an Info file into nodes that correspond to chapters, sections, and the like is a matter of convention, not a requirement.  The `Up', `Previous', and `Next' pointers of a node can point to any other nodes, and a menu can contain any other nodes. Thus, the node structure can be any directed graph.  But it is usually more comprehensible to follow a structure that corresponds to the structure of chapters and sections in a printed book or report.

In addition to menus and to `Next', `Previous', and `Up' pointers, Info provides pointers of another kind, called references, that can be sprinkled throughout the text.  This is usually the best way to represent links that do not fit a hierarchical structure.

Usually, you will design a document so that its nodes match the structure of chapters and sections in the printed output.  But occasionally there are times when this is not right for the material being discussed.  Therefore, Texinfo uses separate commands to specify the node structure for the Info file and the section structure for the printed output.

Generally, you enter an Info file through a node that by convention is named `Top'.  This node normally contains just a brief summary of the file's purpose, and a large menu through which the rest of the file is reached.  From this node, you can either traverse the file systematically by going from node to node, or you can go to a specific node listed in the main menu, or you can search the index menus and then go directly to the node that has the information you want.  Alternatively, with the standalone Info program, you can specify specific menu items on the command line (see Info).

If you want to read through an Info file in sequence, as if it were a printed manual, you can hit SPC repeatedly, or you get the whole file with the advanced Info command g *.  (see Advanced Info commands (info).)

The dir file in the info directory serves as the departure point for the whole Info system.  From it, you can reach the `Top' nodes of each of the documents in a complete Info system.

Printed Books
=============

A Texinfo file can be formatted and typeset as a printed book or manual. To do this, you need TeX, a powerful, sophisticated typesetting program written by Donald Knuth. (You can also use the texi2roff program if you do not have TeX; since Texinfo is designed for use with TeX, texi2roff is not described here. texi2roff is not part of the standard GNU distribution.)

A Texinfo-based book is similar to any other typeset, printed work: it can have a title page, copyright page, table of contents, and preface, as well as chapters, numbered or unnumbered sections and subsections, page headers, cross references, footnotes, and indices.

You can use Texinfo to write a book without ever having the intention of converting it into on-line information.  You can use Texinfo for writing a printed novel, and even to write a printed memo, although this latter application is not recommended since electronic mail is so much easier.

TeX is a general purpose typesetting program.  Texinfo provides a file called texinfo.tex that contains information (definitions or macros) that TeX uses when it typesets a Texinfo file. (texinfo.tex tells TeX how to convert the Texinfo @-commands to TeX commands, which TeX can then process to create the typeset document.)  texinfo.tex contains the specifications for printing a document.

Most often, documents are printed on 8.5 inch by 11 inch pages (216mm by 280mm; this is the default size), but you can also print for 7 inch by 9.25 inch pages (178mm by 235mm; the @smallbook size) or on European A4 size paper (@afourpaper).  (see Printing ``Small'' Books. Also, see Printing on A4 Paper.)

By changing the parameters in texinfo.tex, you can change the size of the printed document.  In addition, you can change the style in which the printed document is formatted; for example, you can change the sizes and fonts used, the amount of indentation for each paragraph, the degree to which words are hyphenated, and the like.  By changing the specifications, you can make a book look dignified, old and serious, or light-hearted, young and cheery.

TeX is freely distributable.  It is written in a superset of Pascal called WEB and can be compiled either in Pascal or (by using a conversion program that comes with the TeX distribution) in C. (see TeX Mode (The GNU Emacs Manual), for information about TeX.)

TeX is very powerful and has a great many features.  Because a Texinfo file must be able to present information both on a character-only terminal in Info form and in a typeset book, the formatting commands that Texinfo supports are necessarily limited.

See How to Obtain TeX.

@-commands
==========

In a Texinfo file, the commands that tell TeX how to typeset the printed manual and tell makeinfo and texinfo-format-buffer how to create an Info file are preceded by @; they are called @-commands.  For example, @node is the command to indicate a node and @chapter is the command to indicate the start of a chapter.

     Please note: All the @-commands, with the exception of the @TeX{} command, must be written entirely in lower case.

The Texinfo @-commands are a strictly limited set of constructs.  The strict limits make it possible for Texinfo files to be understood both by TeX and by the code that converts them into Info files.  You can display Info files on any terminal that displays alphabetic and numeric characters.  Similarly, you can print the output generated by TeX on a wide variety of printers.

Depending on what they do or what arguments (The word argument comes from the way it is used in mathematics and does not refer to a disputation between two people; it refers to the information presented to the command.  According to the Oxford English Dictionary, the word derives from the Latin for to make clear, prove; thus it came to mean `the evidence offered as proof', which is to say, `the information offered', which led to its mathematical meaning.  In its other thread of derivation, the word came to mean `to assert in a manner against which others may make counter assertions', which led to the meaning of `argument' as a disputation.) they take, you need to write @-commands on lines of their own or as part of sentences:

  * Write a command such as @noindent at the beginning of a line as the only text on the line.  (@noindent prevents the beginning of the next line from being indented as the beginning of a paragraph.)

  * Write a command such as @chapter at the beginning of a line followed by the command's arguments, in this case the chapter title, on the rest of the line.  (@chapter creates chapter titles.)

  * Write a command such as @dots{} wherever you wish but usually within a sentence. (@dots{} creates dots ...)

  * Write a command such as @code{SAMPLE-CODE} wherever you wish (but usually within a sentence) with its argument, SAMPLE-CODE in this example, between the braces.  (@code marks text as being code.)

  * Write a command such as @example at the beginning of a line of its own; write the body-text on following lines; and write the matching @end command, @end example in this case, at the beginning of a line of its own after the body-text. (@example ... @end example indents and typesets body-text as an example.)

As a general rule, a command requires braces if it mingles among other text; but it does not need braces if it starts a line of its own.  The non-alphabetic commands, such as @:, are exceptions to the rule; they do not need braces.

As you gain experience with Texinfo, you will rapidly learn how to write the different commands: the different ways to write commands make it easier to write and read Texinfo files than if all commands followed exactly the same syntax.  (For details about @-command syntax, see @-Command Syntax.)

General Syntactic Conventions
=============================

All printable ASCII characters except @, { and } can appear in a Texinfo file and stand for themselves. @ is the escape character which introduces commands. { and } should be used only to surround arguments to certain commands.  To put one of these special characters into the document, put an @ character in front of it, like this: @@, @{, and @}.

It is customary in TeX to use doubled single-quote characters to begin and end quotations: ` ` and ' ' (but without a space between the two single-quote characters).  This convention should be followed in Texinfo files.  TeX converts doubled single-quote characters to left- and right-hand doubled quotation marks and Info converts doubled single-quote characters to ASCII double-quotes: ` ` and ' ' to " .

Use three hyphens in a row, ---, for a dash---like this.  In TeX, a single or double hyphen produces a printed dash that is shorter than the usual typeset dash. Info reduces three hyphens to two for display on the screen.

To prevent a paragraph from being indented in the printed manual, put the command @noindent on a line by itself before the paragraph.

If you mark off a region of the Texinfo file with the @iftex and @end iftex commands, that region will appear only in the printed copy; in that region, you can use certain commands borrowed from plain TeX that you cannot use in Info.  Likewise, if you mark off a region with the @ifinfo and @end ifinfo commands, that region will appear only in the Info file; in that region, you can use Info commands that you cannot use in TeX. Similarly for @ifhtml ... @end ifhtml, @ifnothtml ... @end ifnothtml, @ifnotinfo ... @end ifnotinfo, @ifnottex ... @end ifnottex, see Conditionals.

     Caution: Do not use tabs in a Texinfo file!  TeX uses variable-width fonts, which means that it cannot predefine a tab to work in all circumstances.  Consequently, TeX treats tabs like single spaces, and that is not what they look like.  Furthermore, makeinfo does nothing special with tabs, and thus a tab character in your input file may appear differently in the output.

     To avoid this problem, Texinfo mode causes GNU Emacs to insert multiple spaces when you press the TAB key.

     Also, you can run untabify in Emacs to convert tabs in a region to multiple spaces.

     Don't use tabs.

Comments
========

You can write comments in a Texinfo file that will not appear in either the Info file or the printed manual by using the @comment command (which may be abbreviated to @c). Such comments are for the person who reads the Texinfo file.  All the text on a line that follows either @comment or @c is a comment; the rest of the line does not appear in either the Info file or the printed manual. (Often, you can write the @comment or @c in the middle of a line, and only the text that follows after the @comment or @c command does not appear; but some commands, such as @settitle and @setfilename, work on a whole line.  You cannot use @comment or @c in a line beginning with such a command.)

You can write long stretches of text that will not appear in either the Info file or the printed manual by using the @ignore and @end ignore commands.  Write each of these commands on a line of its own, starting each command at the beginning of the line.  Text between these two commands does not appear in the processed output. You can use @ignore and @end ignore for writing comments.  Often, @ignore and @end ignore is used to enclose a part of the copying permissions that applies to the Texinfo source file of a document, but not to the Info or printed version of the document.

What a Texinfo File Must Have
=============================

By convention, the names of Texinfo files end with one of the extensions .texinfo, .texi, or .tex.  The longer extension is preferred since it describes more clearly to a human reader the nature of the file.  The shorter extensions are for operating systems that cannot handle long file names.

In order to be made into a printed manual and an Info file, a Texinfo file must begin with lines like this:

     \input texinfo
     @setfilename INFO-FILE-NAME
     @settitle NAME-OF-MANUAL

The contents of the file follow this beginning, and then you must end a Texinfo file with a line like this:

     @bye

The \input texinfo line tells TeX to use the texinfo.tex file, which tells TeX how to translate the Texinfo @-commands into TeX typesetting commands.  (Note the use of the backslash, \; this is correct for TeX.)  The @setfilename line provides a name for the Info file and tells TeX to open auxiliary files.  The @settitle line specifies a title for the page headers (or footers) of the printed manual.

The @bye line at the end of the file on a line of its own tells the formatters that the file is ended and to stop formatting.

Usually, you will not use quite such a spare format, but will include mode setting and start-of-header and end-of-header lines at the beginning of a Texinfo file, like this:

     \input texinfo   @c -*-texinfo-*-
     @c %**start of header
     @setfilename INFO-FILE-NAME
     @settitle NAME-OF-MANUAL
     @c %**end of header

In the first line, -*-texinfo-*- causes Emacs to switch into Texinfo mode when you edit the file.

The @c lines which surround the @setfilename and @settitle lines are optional, but you need them in order to run TeX or Info on just part of the file.  (see Start of Header, for more information.)

Furthermore, you will usually provide a Texinfo file with a title page, indices, and the like.  But the minimum, which can be useful for short documents, is just the three lines at the beginning and the one line at the end.

Six Parts of a Texinfo File
===========================

Generally, a Texinfo file contains more than the minimal beginning and end---it usually contains six parts:

1. Header
     The Header names the file, tells TeX which definitions' file to use, and performs other ``housekeeping'' tasks.

2. Summary Description and Copyright
     The Summary Description and Copyright segment describes the document and contains the copyright notice and copying permissions for the Info file.  The segment must be enclosed between @ifinfo and @end ifinfo commands so that the formatters place it only in the Info file.

3. Title and Copyright
     The Title and Copyright segment contains the title and copyright pages and copying permissions for the printed manual.  The segment must be enclosed between @titlepage and @end titlepage commands. The title and copyright page appear only in the printed manual.

4. `Top' Node and Master Menu
     The Master Menu contains a complete menu of all the nodes in the whole Info file.  It appears only in the Info file, in the `Top' node.

5. Body
     The Body of the document may be structured like a traditional book or encyclopedia or it may be free form.

6. End
     The End contains commands for printing indices and generating the table of contents, and the @bye command on a line of its own.

A Short Sample Texinfo File
===========================

Here is a complete but very short Texinfo file, in six parts.  The first three parts of the file, from \input texinfo through to @end titlepage, look more intimidating than they are.  Most of the material is standard boilerplate; when you write a manual, simply insert the names for your own manual in this segment. (see Beginning a File.)

In the following, the sample text is indented; comments on it are not.  The complete file, without any comments, is shown in Sample Texinfo File.

Part 1: Header
--------------

The header does not appear in either the Info file or the printed output.  It sets various parameters, including the name of the Info file and the title used in the header.

     \input texinfo   @c -*-texinfo-*-
     @c %**start of header
     @setfilename sample.info
     @settitle Sample Document
     @c %**end of header

     @setchapternewpage odd

Part 2: Summary Description and Copyright
-----------------------------------------

The summary description and copyright segment does not appear in the printed document.

     @ifinfo
     This is a short example of a complete Texinfo file.

     Copyright @copyright{} 1990 Free Software Foundation, Inc.
     @end ifinfo

Part 3: Titlepage and Copyright
-------------------------------

The titlepage segment does not appear in the Info file.

     @titlepage
     @sp 10
     @comment The title is printed in a large font.
     @center @titlefont{Sample Title}

     @c The following two commands start the copyright page.
     @page
     @vskip 0pt plus 1filll
     Copyright @copyright{} 1990 Free Software Foundation, Inc.
     @end titlepage

Part 4: `Top' Node and Master Menu
----------------------------------

The `Top' node contains the master menu for the Info file. Since a printed manual uses a table of contents rather than a menu, the master menu appears only in the Info file.

     @node    Top,       First Chapter, ,         (dir)
     @comment node-name, next,          previous, up

     @menu
     * First Chapter::    The first chapter is the
                          only chapter in this sample.
     * Concept Index::    This index has two entries.
     @end menu

Part 5: The Body of the Document
--------------------------------

The body segment contains all the text of the document, but not the indices or table of contents.  This example illustrates a node and a chapter containing an enumerated list.

     @node    First Chapter, Concept Index, Top,      Top
     @comment node-name,     next,          previous, up
     @chapter First Chapter
     @cindex Sample index entry

     This is the contents of the first chapter.
     @cindex Another sample index entry

     Here is a numbered list.

     @enumerate
     @item
     This is the first item.

     @item
     This is the second item.
     @end enumerate

     The @code{makeinfo} and @code{texinfo-format-buffer}
     commands transform a Texinfo file such as this into
     an Info file; and @TeX{} typesets it for a printed
     manual.

Part 6: The End of the Document
-------------------------------

The end segment contains commands both for generating an index in a node and unnumbered chapter of its own and for generating the table of contents; and it contains the @bye command that marks the end of the document.

     @node    Concept Index,    ,  First Chapter, Top
     @comment node-name,    next,  previous,      up
     @unnumbered Concept Index

     @printindex cp

     @contents
     @bye

The Results
-----------

Here is what the contents of the first chapter of the sample look like:

     This is the contents of the first chapter.

     Here is a numbered list.

      1. This is the first item.

      2. This is the second item.

     The makeinfo and texinfo-format-buffer commands transform a Texinfo file such as this into an Info file; and TeX typesets it for a printed manual.

Acknowledgements
================

Richard M. Stallman wrote Edition 1.0 of this manual.  Robert J. Chassell revised and extended it, starting with Edition 1.1.  Karl Berry made updates for the Texinfo 3.8 and subsequent releases, starting with Edition 2.22.

Our thanks go out to all who helped improve this work, particularly to François Pinard and David D. Zuhn, who tirelessly recorded and reported mistakes and obscurities; our special thanks go to Melissa Weisshaus for her frequent and often tedious reviews of nearly similar editions.  Our mistakes are our own.

Please send suggestions and corrections to:

     Internet address:
         bug-texinfo@prep.ai.mit.edu

Please include the manual's edition number and update date in your messages.

Using Texinfo Mode
******************

You may edit a Texinfo file with any text editor you choose.  A Texinfo file is no different from any other ASCII file.  However, GNU Emacs comes with a special mode, called Texinfo mode, that provides  Emacs commands and tools to help ease your work.

This chapter describes features of GNU Emacs' Texinfo mode but not any features of the Texinfo formatting language.  If you are reading this manual straight through from the beginning, you may want to skim through this chapter briefly and come back to it after reading succeeding chapters which describe the Texinfo formatting language in detail.

Texinfo Mode Overview
=====================

Texinfo mode provides special features for working with Texinfo files:

  * Insert frequently used @-commands.

  * Automatically create @node lines.

  * Show the structure of a Texinfo source file.

  * Automatically create or update the `Next', `Previous', and `Up' pointers of a node.

  * Automatically create or update menus.

  * Automatically create a master menu.

  * Format a part or all of a file for Info.

  * Typeset and print part or all of a file.

Perhaps the two most helpful features are those for inserting frequently used @-commands and for creating node pointers and menus.

The Usual GNU Emacs Editing Commands
====================================

In most cases, the usual Text mode commands work the same in Texinfo mode as they do in Text mode.  Texinfo mode adds new editing commands and tools to GNU Emacs' general purpose editing features.  The major difference concerns filling.  In Texinfo mode, the paragraph separation variable and syntax table are redefined so that Texinfo commands that should be on lines of their own are not inadvertently included in paragraphs.  Thus, the M-q (fill-paragraph) command will refill a paragraph but not mix an indexing command on a line adjacent to it into the paragraph.

In addition, Texinfo mode sets the page-delimiter variable to the value of texinfo-chapter-level-regexp; by default, this is a regular expression matching the commands for chapters and their equivalents, such as appendices.  With this value for the page delimiter, you can jump from chapter title to chapter title with the C-x ] (forward-page) and C-x [ (backward-page) commands and narrow to a chapter with the C-x p (narrow-to-page) command.  (see Pages (The GNU Emacs Manual), for details about the page commands.)

You may name a Texinfo file however you wish, but the convention is to end a Texinfo file name with one of the three extensions .texinfo, .texi, or .tex.  A longer extension is preferred, since it is explicit, but a shorter extension may be necessary for operating systems that limit the length of file names. GNU Emacs automatically enters Texinfo mode when you visit a file with a .texinfo or  .texi extension.  Also, Emacs switches to Texinfo mode when you visit a file that has -*-texinfo-*- in its first line.  If ever you are in another mode and wish to switch to Texinfo mode, type M-x texinfo-mode.

Like all other Emacs features, you can customize or enhance Texinfo mode as you wish.  In particular, the keybindings are very easy to change.  The keybindings described here are the default or standard ones.

Inserting Frequently Used Commands
==================================

Texinfo mode provides commands to insert various frequently used @-commands into the buffer.  You can use these commands to save keystrokes.

The insert commands are invoked by typing C-c twice and then the first letter of the @-command:

C-c C-c c
M-x texinfo-insert-@code
     Insert @code{} and put the cursor between the braces.

C-c C-c d
M-x texinfo-insert-@dfn
     Insert @dfn{} and put the cursor between the braces.

C-c C-c e
M-x texinfo-insert-@end
     Insert @end and attempt to insert the correct following word, such as example or table.  (This command does not handle nested lists correctly, but inserts the word appropriate to the immediately preceding list.)

C-c C-c i
M-x texinfo-insert-@item
     Insert @item and put the cursor at the beginning of the next line.

C-c C-c k
M-x texinfo-insert-@kbd
     Insert @kbd{} and put the cursor between the braces.

C-c C-c n
M-x texinfo-insert-@node
     Insert @node and a comment line listing the sequence for the `Next', `Previous', and `Up' nodes. Leave point after the @node.

C-c C-c o
M-x texinfo-insert-@noindent
     Insert @noindent and put the cursor at the beginning of the next line.

C-c C-c s
M-x texinfo-insert-@samp
     Insert @samp{} and put the cursor between the braces.

C-c C-c t
M-x texinfo-insert-@table
     Insert @table followed by a SPC and leave the cursor after the SPC.

C-c C-c v
M-x texinfo-insert-@var
     Insert @var{} and put the cursor between the braces.

C-c C-c x
M-x texinfo-insert-@example
     Insert @example and put the cursor at the beginning of the next line.

C-c C-c {
M-x texinfo-insert-braces
     Insert {} and put the cursor between the braces.

C-c C-c }
C-c C-c ]
M-x up-list
     Move from between a pair of braces forward past the closing brace. Typing C-c C-c ] is easier than typing C-c C-c }, which is, however, more mnemonic; hence the two keybindings.  (Also, you can move out from between braces by typing C-f.)

To put a command such as @code{...} around an existing word, position the cursor in front of the word and type C-u 1 C-c C-c c.  This makes it easy to edit existing plain text. The value of the prefix argument tells Emacs how many words following point to include between braces---1 for one word, 2 for two words, and so on.  Use a negative argument to enclose the previous word or words.  If you do not specify a prefix argument, Emacs inserts the @-command string and positions the cursor between the braces.  This feature works only for those @-commands that operate on a word or words within one line, such as @kbd and @var.

This set of insert commands was created after analyzing the frequency with which different @-commands are used in the GNU Emacs Manual and the GDB Manual.  If you wish to add your own insert commands, you can bind a keyboard macro to a key, use abbreviations, or extend the code in texinfo.el.

C-c C-c C-d (texinfo-start-menu-description) is an insert command that works differently from the other insert commands.  It inserts a node's section or chapter title in the space for the description in a menu entry line.  (A menu entry has three parts, the entry name, the node name, and the description.  Only the node name is required, but a description helps explain what the node is about. See The Parts of a Menu.)

To use texinfo-start-menu-description, position point in a menu entry line and type C-c C-c C-d.  The command looks for and copies the title that goes with the node name, and inserts the title as a description; it positions point at beginning of the inserted text so you can edit it.  The function does not insert the title if the menu entry line already contains a description.

This command is only an aid to writing descriptions; it does not do the whole job.  You must edit the inserted text since a title tends to use the same words as a node name but a useful description uses different words.

Showing the Section Structure of a File
=======================================

You can show the section structure of a Texinfo file by using the C-c C-s command (texinfo-show-structure).  This command shows the section structure of a Texinfo file by listing the lines that begin with the @-commands for @chapter, @section, and the like.  It constructs what amounts to a table of contents.  These lines are displayed in another buffer called the *Occur* buffer.  In that buffer, you can position the cursor over one of the lines and use the C-c C-c command (occur-mode-goto-occurrence), to jump to the corresponding spot in the Texinfo file.

C-c C-s
M-x texinfo-show-structure
     Show the @chapter, @section, and such lines of a Texinfo file.

C-c C-c
M-x occur-mode-goto-occurrence
     Go to the line in the Texinfo file corresponding to the line under the cursor in the *Occur* buffer.

If you call texinfo-show-structure with a prefix argument by typing C-u C-c C-s, it will list not only those lines with the @-commands for @chapter, @section, and the like, but also the @node lines.  (This is how the texinfo-show-structure command worked without an argument in the first version of Texinfo.  It was changed because @node lines clutter up the *Occur* buffer and are usually not needed.)  You can use texinfo-show-structure with a prefix argument to check whether the `Next', `Previous', and `Up' pointers of an @node line are correct.

Often, when you are working on a manual, you will be interested only in the structure of the current chapter.  In this case, you can mark off the region of the buffer that you are interested in by using the C-x n n (narrow-to-region) command and texinfo-show-structure will work on only that region.  To see the whole buffer again, use C-x n w (widen). (see Narrowing (The GNU Emacs Manual), for more information about the narrowing commands.)

In addition to providing the texinfo-show-structure command, Texinfo mode sets the value of the page delimiter variable to match the chapter-level @-commands.  This enables you to use the C-x ] (forward-page) and C-x [ (backward-page) commands to move forward and backward by chapter, and to use the C-x p (narrow-to-page) command to narrow to a chapter. See Pages (The GNU Emacs Manual), for more information about the page commands.

Updating Nodes and Menus
========================

Texinfo mode provides commands for automatically creating or updating menus and node pointers.  The commands are called ``update'' commands because their most frequent use is for updating a Texinfo file after you have worked on it; but you can use them to insert the `Next', `Previous', and `Up' pointers into an @node line that has none and to create menus in a file that has none.

If you do not use the updating commands, you need to write menus and node pointers by hand, which is a tedious task.

The Updating Commands
---------------------

You can use the updating commands

  * to insert or update the `Next', `Previous', and `Up' pointers of a node,

  * to insert or update the menu for a section, and

  * to create a master menu for a Texinfo source file.

You can also use the commands to update all the nodes and menus in a region or in a whole Texinfo file.

The updating commands work only with conventional Texinfo files, which are structured hierarchically like books.  In such files, a structuring command line must follow closely after each @node line, except for the `Top' @node line.  (A structuring command line is a line beginning with @chapter, @section, or other similar command.)

You can write the structuring command line on the line that follows immediately after an @node line or else on the line that follows after a single @comment line or a single @ifinfo line.  You cannot interpose more than one line between the @node line and the structuring command line; and you may interpose only an @comment line or an @ifinfo line.

Commands which work on a whole buffer require that the `Top' node be followed by a node with an @chapter or equivalent-level command. Note that the menu updating commands will not create a main or master menu for a Texinfo file that has only @chapter-level nodes!  The menu updating commands only create menus within nodes for lower level nodes.  To create a menu of chapters, you must provide a `Top' node.

The menu updating commands remove menu entries that refer to other Info files since they do not refer to nodes within the current buffer.  This is a deficiency.  Rather than use menu entries, you can use cross references to refer to other Info files.  None of the updating commands affect cross references.

Texinfo mode has five updating commands that are used most often: two are for updating the node pointers or menu of a single node (or a region); two are for updating every node pointer and menu in a file; and one, the texinfo-master-menu command, is for creating a master menu for a complete file, and optionally, for updating every node and menu in the whole Texinfo file.

The texinfo-master-menu command is the primary command:

C-c C-u m
M-x texinfo-master-menu
     Create or update a master menu that includes all the other menus (incorporating the descriptions from pre-existing menus, if any).

     With an argument (prefix argument, C-u, if interactive), first create or update all the nodes and all the regular menus in the buffer before constructing the master menu.  (see The Top Node and Master Menu, for more about a master menu.)

     For texinfo-master-menu to work, the Texinfo file must have a `Top' node and at least one subsequent node.

     After extensively editing a Texinfo file, you can type the following:

          C-u M-x texinfo-master-menu
          or
          C-u C-c C-u m

     This updates all the nodes and menus completely and all at once.

The other major updating commands do smaller jobs and are designed for the person  who updates nodes and menus as he or she writes a Texinfo file.

The commands are:

C-c C-u C-n
M-x texinfo-update-node
     Insert the `Next', `Previous', and `Up' pointers for the node that point is within (i.e., for the @node line preceding point).  If the @node line has pre-existing `Next', `Previous', or `Up' pointers in it, the old pointers are removed and new ones inserted. With an argument (prefix argument, C-u, if interactive), this command updates all @node lines in the region (which is the text between point and mark).

C-c C-u C-m
M-x texinfo-make-menu
     Create or update the menu in the node that point is within. With an argument (C-u as prefix argument, if interactive), the command makes or updates menus for the nodes which are either within or a part of the region.

     Whenever texinfo-make-menu updates an existing menu, the descriptions from that menu are incorporated into the new menu.  This is done by copying descriptions from the existing menu to the entries in the new menu that have the same node names.  If the node names are different, the descriptions are not copied to the new menu.

C-c C-u C-e
M-x texinfo-every-node-update
     Insert or update the `Next', `Previous', and `Up' pointers for every node in the buffer.

C-c C-u C-a
M-x texinfo-all-menus-update
     Create or update all the menus in the buffer.  With an argument (C-u as prefix argument, if interactive), first insert or update all the node pointers before working on the menus.

     If a master menu exists, the texinfo-all-menus-update command updates it; but the command does not create a new master menu if none already exists.  (Use the texinfo-master-menu command for that.)

     When working on a document that does not merit a master menu, you can type the following:

          C-u C-c C-u C-a
          or
          C-u M-x texinfo-all-menus-update

     This updates all the nodes and menus.

The texinfo-column-for-description variable specifies the column to which menu descriptions are indented.  By default, the value is 32 although it is often useful to reduce it to as low as 24.  You can set the variable with the M-x edit-options command (see Editing Variable Values (The GNU Emacs Manual)) or with the M-x set-variable command (see Examining and Setting Variables (The GNU Emacs Manual)).

Also, the texinfo-indent-menu-description command may be used to indent existing menu descriptions to a specified column.  Finally, if you wish, you can use the texinfo-insert-node-lines command to insert missing @node lines into a file.  (see Other Updating Commands, for more information.)

Updating Requirements
---------------------

To use the updating commands, you must organize the Texinfo file hierarchically with chapters, sections, subsections, and the like. When you construct the hierarchy of the manual, do not `jump down' more than one level at a time: you can follow the `Top' node with a chapter, but not with a section; you can follow a chapter with a section, but not with a subsection.  However, you may `jump up' any number of levels at one time---for example, from a subsection to a chapter.

Each @node line, with the exception of the line for the `Top' node, must be followed by a line with a structuring command such as @chapter, @section, or @unnumberedsubsec.

Each @node line/structuring-command line combination must look either like this:

     @node     Comments,  Minimum, Conventions, Overview
     @comment  node-name, next,    previous,    up
     @section Comments

or like this (without the @comment line):

     @node Comments, Minimum, Conventions, Overview
     @section Comments

In this example, `Comments' is the name of both the node and the section.  The next node is called `Minimum' and the previous node is called `Conventions'.  The `Comments' section is within the `Overview' node, which is specified by the `Up' pointer.  (Instead of an @comment line, you can write an @ifinfo line.)

If a file has a `Top' node, it must be called top or Top and be the first node in the file.

The menu updating commands create a menu of sections within a chapter, a menu of subsections within a section, and so on.  This means that you must have a `Top' node if you want a menu of chapters.

Incidentally, the makeinfo command will create an Info file for a hierarchically organized Texinfo file that lacks `Next', `Previous' and `Up' pointers.  Thus, if you can be sure that your Texinfo file will be formatted with makeinfo, you have no need for the `update node' commands.  (see Creating an Info File, for more information about makeinfo.)  However, both makeinfo and the texinfo-format-... commands require that you insert menus in the file.

Other Updating Commands
-----------------------

In addition to the five major updating commands, Texinfo mode possesses several less frequently used updating commands:

M-x texinfo-insert-node-lines
     Insert @node lines before the @chapter, @section, and other sectioning commands wherever they are missing throughout a region in a Texinfo file.

     With an argument (C-u as prefix argument, if interactive), the texinfo-insert-node-lines command not only inserts @node lines but also inserts the chapter or section titles as the names of the corresponding nodes.  In addition, it inserts the titles as node names in pre-existing @node lines that lack names.  Since node names should be more concise than section or chapter titles, you must manually edit node names so inserted.

     For example, the following marks a whole buffer as a region and inserts @node lines and titles throughout:

          C-x h C-u M-x texinfo-insert-node-lines

     (Note that this command inserts titles as node names in @node lines; the texinfo-start-menu-description command (see Inserting Frequently Used Commands) inserts titles as descriptions in menu entries, a different action.  However, in both cases, you need to edit the inserted text.)

M-x texinfo-multiple-files-update
     Update nodes and menus in a document built from several separate files. With C-u as a prefix argument, create and insert a master menu in the outer file.  With a numeric prefix argument, such as C-u 2, first update all the menus and all the `Next', `Previous', and `Up' pointers of all the included files before creating and inserting a master menu in the outer file.  The texinfo-multiple-files-update command is described in the appendix on @include files. See texinfo-multiple-files-update.

M-x texinfo-indent-menu-description
     Indent every description in the menu following point to the specified column.  You can use this command to give yourself more space for descriptions.  With an argument (C-u as prefix argument, if interactive), the texinfo-indent-menu-description command indents every description in every menu in the region.  However, this command does not indent the second and subsequent lines of a multi-line description.

M-x texinfo-sequential-node-update
     Insert the names of the nodes immediately following and preceding the current node as the `Next' or `Previous' pointers regardless of those nodes' hierarchical level.  This means that the `Next' node of a subsection may well be the next chapter.  Sequentially ordered nodes are useful for novels and other documents that you read through sequentially.  (However, in Info, the g * command lets you look through the file sequentially, so sequentially ordered nodes are not strictly necessary.)  With an argument (prefix argument, if interactive), the texinfo-sequential-node-update command sequentially updates all the nodes in the region.

Formatting for Info
===================

Texinfo mode provides several commands for formatting part or all of a Texinfo file for Info.  Often, when you are writing a document, you want to format only part of a file---that is, a region.

You can use either the texinfo-format-region or the makeinfo-region command to format a region:

C-c C-e C-r
M-x texinfo-format-region
C-c C-m C-r
M-x makeinfo-region
     Format the current region for Info.

You can use either the texinfo-format-buffer or the makeinfo-buffer command to format a whole buffer:

C-c C-e C-b
M-x texinfo-format-buffer
C-c C-m C-b
M-x makeinfo-buffer
     Format the current buffer for Info.

For example, after writing a Texinfo file, you can type the following:

     C-u C-c C-u m
     or
     C-u M-x texinfo-master-menu

This updates all the nodes and menus.  Then type the following to create an Info file:

     C-c C-m C-b
     or
     M-x makeinfo-buffer

For TeX or the Info formatting commands to work, the file must include a line that has @setfilename in its header.

See Create an Info File, for details about Info formatting.

Formatting and Printing
=======================

Typesetting and printing a Texinfo file is a multi-step process in which you first create a file for printing (called a DVI file), and then print the file.  Optionally, you may also create indices.  To do this, you must run the texindex command after first running the tex typesetting command; and then you must run the tex command again.  Or else run the texi2dvi command which automatically creates indices as needed.

Often, when you are writing a document, you want to typeset and print only part of a file to see what it will look like.  You can use the texinfo-tex-region and related commands for this purpose.  Use the texinfo-tex-buffer command to format all of a buffer.

C-c C-t C-b
M-x texinfo-tex-buffer
     Run texi2dvi on the buffer.  In addition to running TeX on the buffer, this command automatically creates or updates indices as needed.

C-c C-t C-r
M-x texinfo-tex-region
     Run TeX on the region.

C-c C-t C-i
M-x texinfo-texindex
     Run texindex to sort the indices of a Texinfo file formatted with texinfo-tex-region.  The texinfo-tex-region command does not run texindex automatically; it only runs the tex typesetting command.  You must run the texinfo-tex-region command a second time after sorting the raw index files with the texindex command.  (Usually, you do not format an index when you format a region, only when you format a buffer.  Now that the texi2dvi command exists, there is little or no need for this command.)

C-c C-t C-p
M-x texinfo-tex-print
     Print the file (or the part of the file) previously formatted with texinfo-tex-buffer or texinfo-tex-region.

For texinfo-tex-region or texinfo-tex-buffer to work, the file must start with a \input texinfo line and must include an @settitle line.  The file must end with @bye on a line by itself.  (When you use texinfo-tex-region, you must surround the @settitle line with start-of-header and end-of-header lines.)

See Format/Print Hardcopy, for a description of the other TeX related commands, such as tex-show-print-queue.

Texinfo Mode Summary
====================

In Texinfo mode, each set of commands has default keybindings that begin with the same keys.  All the commands that are custom-created for Texinfo mode begin with C-c.  The keys are somewhat mnemonic.

Insert Commands
---------------

The insert commands are invoked by typing C-c twice and then the first letter of the @-command to be inserted.  (It might make more sense mnemonically to use C-c C-i, for `custom insert', but C-c C-c is quick to type.)

     C-c C-c c       Insert @code.
     C-c C-c d       Insert @dfn.
     C-c C-c e       Insert @end.
     C-c C-c i       Insert @item.
     C-c C-c n       Insert @node.
     C-c C-c s       Insert @samp.
     C-c C-c v       Insert @var.
     C-c C-c {       Insert braces.
     C-c C-c ]
     C-c C-c }       Move out of enclosing braces.

     C-c C-c C-d     Insert a node's section title
                     in the space for the description
                     in a menu entry line.

Show Structure
--------------

The texinfo-show-structure command is often used within a narrowed region.

     C-c C-s         List all the headings.

The Master Update Command
-------------------------

The texinfo-master-menu command creates a master menu; and can be used to update every node and menu in a file as well.

     C-c C-u m
     M-x texinfo-master-menu
                     Create or update a master menu.

     C-u C-c C-u m   With C-u as a prefix argument, first
                     create or update all nodes and regular
                     menus, and then create a master menu.

Update Pointers
---------------

The update pointer commands are invoked by typing C-c C-u and then either C-n for texinfo-update-node or C-e for texinfo-every-node-update.

     C-c C-u C-n     Update a node.
     C-c C-u C-e     Update every node in the buffer.

Update Menus
------------

Invoke the  update menu commands by typing C-c C-u and then either C-m for texinfo-make-menu or C-a for texinfo-all-menus-update.  To update both nodes and menus at the same time, precede C-c C-u C-a with C-u.

     C-c C-u C-m     Make or update a menu.

     C-c C-u C-a     Make or update all
                     menus in a buffer.

     C-u C-c C-u C-a With C-u as a prefix argument,
                     first create or update all nodes and
                     then create or update all menus.

Format for Info
---------------

The Info formatting commands that are written in Emacs Lisp are invoked by typing C-c C-e and then either C-r for a region or C-b for the whole buffer.

The Info formatting commands that are written in C and based on the makeinfo program are invoked by typing C-c C-m and then either C-r for a region or C-b for the whole buffer.

Use the texinfo-format... commands:

     C-c C-e C-r     Format the region.
     C-c C-e C-b     Format the buffer.

Use makeinfo:

     C-c C-m C-r     Format the region.
     C-c C-m C-b     Format the buffer.
     C-c C-m C-l     Recenter the makeinfo output buffer.
     C-c C-m C-k     Kill the makeinfo formatting job.

Typeset and Print
-----------------

The TeX typesetting and printing commands are invoked by typing C-c C-t and then another control command: C-r for texinfo-tex-region, C-b for texinfo-tex-buffer, and so on.

     C-c C-t C-r     Run TeX on the region.
     C-c C-t C-b     Run texi2dvi on the buffer.
     C-c C-t C-i     Run texindex.
     C-c C-t C-p     Print the DVI file.
     C-c C-t C-q     Show the print queue.
     C-c C-t C-d     Delete a job from the print queue.
     C-c C-t C-k     Kill the current TeX formatting job.
     C-c C-t C-x     Quit a currently stopped TeX formatting job.
     C-c C-t C-l     Recenter the output buffer.

Other Updating Commands
-----------------------

The `other updating commands' do not have standard keybindings because they are rarely used.

     M-x texinfo-insert-node-lines
                     Insert missing @node lines in region.
                     With C-u as a prefix argument,
                     use section titles as node names.

     M-x texinfo-multiple-files-update
                     Update a multi-file document.
                     With C-u 2 as a prefix argument,
                     create or update all nodes and menus
                     in all included files first.

     M-x texinfo-indent-menu-description
                     Indent descriptions.

     M-x texinfo-sequential-node-update
                     Insert node pointers in strict sequence.

Beginning a Texinfo File
************************

Certain pieces of information must be provided at the beginning of a Texinfo file, such as the name of the file and the title of the document.

Four Parts Begin a File
=======================

Generally, the beginning of a Texinfo file has four parts:

 1. The header, delimited by special comment lines, that includes the commands for naming the Texinfo file and telling TeX what definitions file to use when processing the Texinfo file.

 2. A short statement of what the file is about, with a copyright notice and copying permissions.  This is enclosed in @ifinfo and @end ifinfo commands so that the formatters place it only in the Info file.

 3. A title page and copyright page, with a copyright notice and copying permissions.  This is enclosed between @titlepage and @end titlepage commands.  The title and copyright page appear only in the printed manual.

 4. The `Top' node that contains a menu for the whole Info file.  The contents of this node appear only in the Info file.

Also, optionally, you may include the copying conditions for a program and a warranty disclaimer.  The copying section will be followed by an introduction or else by the first chapter of the manual.

Since the copyright notice and copying permissions for the Texinfo document (in contrast to the copying permissions for a program) are in parts that appear only in the Info file or only in the printed manual, this information must be given twice.

Sample Texinfo File Beginning
=============================

The following sample shows what is needed.

     \input texinfo   @c -*-texinfo-*-
     @c %**start of header
     @setfilename NAME-OF-INFO-FILE
     @settitle NAME-OF-MANUAL
     @setchapternewpage odd
     @c %**end of header

     @ifinfo
     This file documents ...

     Copyright YEAR COPYRIGHT-OWNER

     Permission is granted to ...
     @end ifinfo

     @c  This title page illustrates only one of the
     @c  two methods of forming a title page.

     @titlepage
     @title NAME-OF-MANUAL-WHEN-PRINTED
     @subtitle SUBTITLE-IF-ANY
     @subtitle SECOND-SUBTITLE
     @author AUTHOR

     @c  The following two commands
     @c  start the copyright page.
     @page
     @vskip 0pt plus 1filll
     Copyright @copyright{} YEAR COPYRIGHT-OWNER

     Published by ...

     Permission is granted to ...
     @end titlepage

     @node Top, Overview, , (dir)

     @ifinfo
     This document describes ...

     This document applies to version ...
     of the program named ...
     @end ifinfo

     @menu
     * Copying::          Your rights and freedoms.
     * First Chapter::    Getting started ...
     * Second Chapter::              ...
       ...
       ...
     @end menu

     @node    First Chapter, Second Chapter, top,      top
     @comment node-name,     next,           previous, up
     @chapter First Chapter
     @cindex Index entry for First Chapter

The Texinfo File Header
=======================

Texinfo files start with at least three lines that provide Info and TeX with necessary information.  These are the \input texinfo line, the @settitle line, and the @setfilename line.  If you want to run TeX on just a part of the Texinfo File, you must write the @settitle and @setfilename lines between start-of-header and end-of-header lines.

Thus, the beginning of a Texinfo file looks like this:

     \input texinfo   @c -*-texinfo-*-
     @setfilename sample.info
     @settitle Sample Document

or else like this:

     \input texinfo   @c -*-texinfo-*-
     @c %**start of header
     @setfilename sample.info
     @settitle Sample Document
     @c %**end of header

The First Line of a Texinfo File
--------------------------------

Every Texinfo file that is to be the top-level input to TeX must begin with a line that looks like this:

     \input texinfo   @c -*-texinfo-*-

This line serves two functions:

 1. When the file is processed by TeX, the \input texinfo command tells TeX to load the macros needed for processing a Texinfo file. These are in a file called texinfo.tex, which is usually located in the /usr/lib/tex/macros directory.  TeX uses the backslash, \, to mark the beginning of a command, just as Texinfo uses @.  The texinfo.tex file causes the switch from \ to @; before the switch occurs, TeX requires \, which is why it appears at the beginning of the file.

 2. When the file is edited in GNU Emacs, the -*-texinfo-*- mode specification tells Emacs to use Texinfo mode.

Start of Header
---------------

Write a start-of-header line on the second line of a Texinfo file. Follow the start-of-header line with @setfilename and @settitle lines and, optionally, with other command lines, such as @smallbook or @footnotestyle; and then by an end-of-header line (see End of Header).

With these lines, you can format part of a Texinfo file for Info or typeset part for printing.

A start-of-header line looks like this:

     @c %**start of header

The odd string of characters, %**, is to ensure that no other comment is accidentally taken for a start-of-header line.

@setfilename
------------

In order to serve as the primary input file for either makeinfo or TeX, a Texinfo file must contain a line that looks like this:

     @setfilename INFO-FILE-NAME

Write the @setfilename command at the beginning of a line and follow it on the same line by the Info file name.  Do not write anything else on the line; anything on the line after the command is considered part of the file name, including what would otherwise be a comment.

The @setfilename line specifies the name of the Info file to be generated.  This name should be different from the name of the Texinfo file.  There are two conventions for choosing the name: you can either remove the .texi extension from the input file name, or replace it with the .info extension.

Some operating systems cannot handle long file names.  You can run into a problem even when the file name you specify is itself short enough. This occurs because the Info formatters split a long Info file into short indirect subfiles, and name them by appending -1, -2, ..., -10, -11, and so on, to the original file name.  (see Tag Files and Split Files.) The subfile name texinfo.info-10, for example, is too long for some systems; so the Info file name for this document is texinfo rather than texinfo.info.

The Info formatting commands ignore everything written before the @setfilename line, which is why the very first line of the file (the \input line) does not need to be commented out.

The @setfilename line produces no output when you typeset a manual with TeX, but it nevertheless is essential: it opens the index, cross-reference, and other auxiliary files used by Texinfo, and also reads texinfo.cnf if that file is present on your system (see Preparing to Use TeX).

@settitle
---------

In order to be made into a printed manual, a Texinfo file must contain a line that looks like this:

     @settitle TITLE

Write the @settitle command at the beginning of a line and follow it on the same line by the title.  This tells TeX the title to use in a header or footer.  Do not write anything else on the line; anything on the line after the command is considered part of the title, including a comment.

Conventionally, when TeX formats a Texinfo file for double-sided output, the title is printed in the left-hand (even-numbered) page headings and the current chapter title is printed in the right-hand (odd-numbered) page headings.  (TeX learns the title of each chapter from each @chapter command.)  Page footers are not printed.

Even if you are printing in a single-sided style, TeX looks for an @settitle command line, in case you include the manual title in the heading.

The @settitle command should precede everything that generates actual output in TeX.

Although the title in the @settitle command is usually the same as the title on the title page, it does not affect the title as it appears on the title page.  Thus, the two do not need not match exactly;  and the title in the @settitle command can be a shortened or expanded version of the title as it appears on the title page. (see @titlepage.)

TeX prints page headings only for that text that comes after the @end titlepage command in the Texinfo file, or that comes after an @headings command that turns on headings. (see The @headings Command, for more information.)

You may, if you wish, create your own, customized headings and footings.  See Page Headings, for a detailed discussion of this process.

@setchapternewpage
------------------

In a book or a manual, text is usually printed on both sides of the paper, chapters start on right-hand pages, and right-hand pages have odd numbers.  But in short reports, text often is printed only on one side of the paper.  Also in short reports, chapters sometimes do not start on new pages, but are printed on the same page as the end of the preceding chapter, after a small amount of vertical whitespace.

You can use the @setchapternewpage command with various arguments to specify how TeX should start chapters and whether it should typeset pages for printing on one or both sides of the paper (single-sided or double-sided printing).

Write the @setchapternewpage command at the beginning of a line followed by its argument.

For example, you would write the following to cause each chapter to start on a fresh odd-numbered page:

     @setchapternewpage odd

You can specify one of three alternatives with the @setchapternewpage command:

@setchapternewpage off
     Cause TeX to typeset a new chapter on the same page as the last chapter, after skipping some vertical whitespace.  Also, cause TeX to format page headers for single-sided printing. (You can override the headers format with the @headings double command; see The @headings Command.)

@setchapternewpage on
     Cause TeX to start new chapters on new pages and to typeset page headers for single-sided printing.  This is the form most often used for short reports.

     This alternative is the default.

@setchapternewpage odd
     Cause TeX to start new chapters on new, odd-numbered pages (right-handed pages) and to typeset for double-sided printing.  This is the form most often used for books and manuals.

Texinfo does not have an @setchapternewpage even command.

(You can countermand or modify an @setchapternewpage command with an @headings command.  See The @headings Command.)

At the beginning of a manual or book, pages are not numbered---for example, the title and copyright pages of a book are not numbered. By convention, table of contents pages are numbered with roman numerals and not in sequence with the rest of the document.

Since an Info file does not have pages, the @setchapternewpage command has no effect on it.

Usually, you do not write an @setchapternewpage command for single-sided printing, but accept the default which is to typeset for single-sided printing and to start new chapters on new pages.  Usually, you write an @setchapternewpage odd command for double-sided printing.

Paragraph Indenting
-------------------

The Info formatting commands may insert spaces at the beginning of the first line of each paragraph, thereby indenting that paragraph.  You can use the @paragraphindent command to specify the indentation.  Write an @paragraphindent command at the beginning of a line followed by either asis or a number.  The template is:

     @paragraphindent INDENT

The Info formatting commands indent according to the value of INDENT:

  * If the value of INDENT is asis, the Info formatting commands do not change the existing indentation.

  * If the value of INDENT is zero, the Info formatting commands delete existing indentation.

  * If the value of INDENT is greater than zero, the Info formatting commands indent the paragraph by that number of spaces.

The default value of INDENT is asis.

Write the @paragraphindent command before or shortly after the end-of-header line at the beginning of a Texinfo file.  (If you write the command between the start-of-header and end-of-header lines, the region formatting commands indent paragraphs as specified.)

A peculiarity of the texinfo-format-buffer and texinfo-format-region commands is that they do not indent (nor fill) paragraphs that contain @w or @* commands. See Refilling Paragraphs, for a detailed description of what goes on.

End of Header
-------------

Follow the header lines with an end-of-header line. An end-of-header line looks like this:

     @c %**end of header

If you include the @setchapternewpage command between the start-of-header and end-of-header lines, TeX will typeset a region as that command specifies.  Similarly, if you include an @smallbook command between the start-of-header and end-of-header lines, TeX will typeset a region in the ``small'' book format.

The reason for the odd string of characters (%**) is so that the texinfo-tex-region command does not accidentally find something that it should not when it is looking for the header.

The start-of-header line and the end-of-header line are Texinfo mode variables that you can change.

Summary and Copying Permissions for Info
========================================

The title page and the copyright page appear only in the printed copy of the manual; therefore, the same information must be inserted in a section that appears only in the Info file.  This section usually contains a brief description of the contents of the Info file, a copyright notice, and copying permissions.

The copyright notice should read:

     Copyright YEAR COPYRIGHT-OWNER

and be put on a line by itself.

Standard text for the copyright permissions is contained in an appendix to this manual; see ifinfo Copying Permissions, for the complete text.

The permissions text appears in an Info file before the first node.  This mean that a reader does not see this text when reading the file using Info, except when using the advanced Info command g *.

The Title and Copyright Pages
=============================

A manual's name and author are usually printed on a title page. Sometimes copyright information is printed on the title page as well; more often, copyright information is printed on the back of the title page.

The title and copyright pages appear in the printed manual, but not in the Info file.  Because of this, it is possible to use several slightly obscure TeX typesetting commands that cannot be used in an Info file. In addition, this part of the beginning of a Texinfo file contains the text of the copying permissions that will appear in the printed manual.

See Titlepage Copying Permissions, for the standard text for the copyright permissions.

@titlepage
----------

Start the material for the title page and following copyright page with @titlepage on a line by itself and end it with @end titlepage on a line by itself.

The @end titlepage command starts a new page and turns on page numbering.  (see Page Headings, for details about how to generate page headings.)  All the material that you want to appear on unnumbered pages should be put between the @titlepage and @end titlepage commands.  By using the @page command you can force a page break within the region delineated by the @titlepage and @end titlepage commands and thereby create more than one unnumbered page.  This is how the copyright page is produced.  (The @titlepage command might perhaps have been better named the @titleandadditionalpages command, but that would have been rather long!)

When you write a manual about a computer program, you should write the version of the program to which the manual applies on the title page.  If the manual changes more frequently than the program or is independent of it, you should also include an edition number (We have found that it is helpful to refer to versions of manuals as `editions' and versions of programs as `versions'; otherwise, we find we are liable to confuse each other in conversation by referring to both the documentation and the software with the same words.) for the manual.  This helps readers keep track of which manual is for which version of the program.  (The `Top' node should also contain this information; see @top.)

Texinfo provides two main methods for creating a title page.  One method uses the @titlefont, @sp, and @center commands to generate a title page in which the words on the page are centered.

The second method uses the @title, @subtitle, and @author commands to create a title page with black rules under the title and author lines and the subtitle text set flush to the right hand side of the page.  With this method, you do not specify any of the actual formatting of the title page.  You specify the text you want, and Texinfo does the formatting.  You may use either method.

For extremely simple applications, Texinfo also provides a command @shorttitlepage which takes a single argument as the title. The argument is typeset on a page by itself and followed by a blank page.

@titlefont, @center, and @sp
----------------------------

You can use the @titlefont, @sp, and @center commands to create a title page for a printed document.  (This is the first of the two methods for creating a title page in Texinfo.)

Use the @titlefont command to select a large font suitable for the title itself.

For example:

     @titlefont{Texinfo}

Use the @center command at the beginning of a line to center the remaining text on that line.  Thus,

     @center @titlefont{Texinfo}

centers the title, which in this example is ``Texinfo'' printed in the title font.

Use the @sp command to insert vertical space.  For example:

     @sp 2

This inserts two blank lines on the printed page.  (see @sp, for more information about the @sp command.)

A template for this method looks like this:

     @titlepage
     @sp 10
     @center @titlefont{NAME-OF-MANUAL-WHEN-PRINTED}
     @sp 2
     @center SUBTITLE-IF-ANY
     @sp 2
     @center AUTHOR
     ...
     @end titlepage

The spacing of the example fits an 8 1/2 by 11 inch manual.

@title, @subtitle, and @author
------------------------------

You can use the @title, @subtitle, and @author commands to create a title page in which the vertical and horizontal spacing is done for you automatically.  This contrasts with the method described in the previous section, in which the @sp command is needed to adjust vertical spacing.

Write the @title, @subtitle, or @author commands at the beginning of a line followed by the title, subtitle, or author.

The @title command produces a line in which the title is set flush to the left-hand side of the page in a larger than normal font. The title is underlined with a black rule.

The @subtitle command sets subtitles in a normal-sized font flush to the right-hand side of the page.

The @author command sets the names of the author or authors in a middle-sized font flush to the left-hand side of the page on a line near the bottom of the title page.  The names are underlined with a black rule that is thinner than the rule that underlines the title. (The black rule only occurs if the @author command line is followed by an @page command line.)

There are two ways to use the @author command: you can write the name or names on the remaining part of the line that starts with an @author command:

     @author by Jane Smith and John Doe

or you can write the names one above each other by using two (or more) @author commands:

     @author Jane Smith
     @author John Doe

(Only the bottom name is underlined with a black rule.)

A template for this method looks like this:

     @titlepage
     @title NAME-OF-MANUAL-WHEN-PRINTED
     @subtitle SUBTITLE-IF-ANY
     @subtitle SECOND-SUBTITLE
     @author AUTHOR
     @page
     ...
     @end titlepage

Contrast this form with the form of a title page written using the @sp, @center, and @titlefont commands:

     @titlepage
     @sp 10
     @center @titlefont{Name of Manual When Printed}
     @sp 2
     @center Subtitle, If Any
     @sp 1
     @center Second subtitle
     @sp 2
     @center Author
     @page
     ...
     @end titlepage

Copyright Page and Permissions
------------------------------

By international treaty, the copyright notice for a book should be either on the title page or on the back of the title page.  The copyright notice should include the year followed by the name of the organization or person who owns the copyright.

When the copyright notice is on the back of the title page, that page is customarily not numbered.  Therefore, in Texinfo, the information on the copyright page should be within @titlepage and @end titlepage commands.

Use the @page command to cause a page break.  To push the copyright notice and the other text on the copyright page towards the bottom of the page, you can write a somewhat mysterious line after the @page command that reads like this:

     @vskip 0pt plus 1filll

This is a TeX command that is not supported by the Info formatting commands.  The @vskip command inserts whitespace.  The 0pt plus 1filll means to put in zero points of mandatory whitespace, and as much optional whitespace as needed to push the following text to the bottom of the page.  Note the use of three ls in the word filll; this is the correct usage in TeX.

In a printed manual, the @copyright{} command generates a c inside a circle.  (In Info, it generates (C).)  The copyright notice itself has the following legally defined sequence:

     Copyright © YEAR COPYRIGHT-OWNER

It is customary to put information on how to get a manual after the copyright notice, followed by the copying permissions for the manual.

Note that permissions must be given here as well as in the summary segment within @ifinfo and @end ifinfo that immediately follows the header since this text appears only in the printed manual and the ifinfo text appears only in the Info file.

See Sample Permissions, for the standard text.

Heading Generation
------------------

An @end titlepage command on a line by itself not only marks the end of the title and copyright pages, but also causes TeX to start generating page headings and page numbers.

To repeat what is said elsewhere,  Texinfo has two standard page heading formats, one for documents which are printed on one side of each sheet of paper (single-sided printing), and the other for documents which are printed on both sides of each sheet (double-sided printing). (see @setchapternewpage.) You can specify these formats in different ways:

  * The conventional way is to write an @setchapternewpage command before the title page commands, and then have the @end titlepage command start generating page headings in the manner desired. (see @setchapternewpage.)

  * Alternatively, you can use the @headings command to prevent page headings from being generated or to start them for either single or double-sided printing.  (Write an @headings command immediately after the @end titlepage command.  See The @headings Command, for more information.)

  * Or, you may specify your own page heading and footing format. See Page Headings, for detailed information about page headings and footings.

Most documents are formatted with the standard single-sided or double-sided format, using @setchapternewpage odd for double-sided printing and no @setchapternewpage command for single-sided printing.

The @headings Command
---------------------

The @headings command is rarely used.  It specifies what kind of page headings and footings to print on each page.  Usually, this is controlled by the @setchapternewpage command.  You need the @headings command only if the @setchapternewpage command does not do what you want, or if you want to turn off pre-defined page headings prior to defining your own.  Write an @headings command immediately after the @end titlepage command.

You can use @headings as follows:

@headings off
     Turn off printing of page headings.

@headings single
     Turn on page headings appropriate for single-sided printing.

@headings double
     Turn on page headings appropriate for double-sided printing.  The two commands, @headings on and @headings double, are synonymous.

@headings singleafter
@headings doubleafter
     Turn on single or double headings, respectively, after the current page is output.

@headings on
     Turn on page headings: single if @setchapternewpage on, double otherwise.

For example, suppose you write @setchapternewpage off before the @titlepage command to tell TeX to start a new chapter on the same page as the end of the last chapter.  This command also causes TeX to typeset page headers for single-sided printing.  To cause TeX to typeset for double sided printing, write @headings double after the @end titlepage command.

You can stop TeX from generating any page headings at all by writing @headings off on a line of its own immediately after the line containing the @end titlepage command, like this:

     @end titlepage
     @headings off

The @headings off command overrides the @end titlepage command, which would otherwise cause TeX to print page headings.

You can also specify your own style of page heading and footing. See Page Headings, for more information.

The `Top' Node and Master Menu
==============================

The `Top' node is the node from which you enter an Info file.

A `Top' node should contain a brief description of the Info file and an extensive, master menu for the whole Info file. This helps the reader understand what the Info file is about.  Also, you should write the version number of the program to which the Info file applies; or, at least, the edition number.

The contents of the `Top' node should appear only in the Info file; none of it should appear in printed output, so enclose it between @ifinfo and @end ifinfo commands.  (TeX does not print either an @node line or a menu; they appear only in Info; strictly speaking, you are not required to enclose these parts between @ifinfo and @end ifinfo, but it is simplest to do so. See Conditionally Visible Text.)

`Top' Node Title
----------------

Sometimes, you will want to place an @top sectioning command line containing the title of the document immediately after the @node Top line (see The @top Sectioning Command, for more information).

For example, the beginning of the Top node of this manual contains an @top sectioning command, a short description, and edition and version information.  It looks like this:

     ...
     @end titlepage

     @ifinfo
     @node Top, Copying, , (dir)
     @top Texinfo

     Texinfo is a documentation system...

     This is edition...
     ...
     @end ifinfo

     @menu
     * Copying::                 Texinfo is freely
                                   redistributable.
     * Overview::                What is Texinfo?
     ...

     @end menu

In a `Top' node, the `Previous', and `Up' nodes usually refer to the top level directory of the whole Info system, which is called (dir). The `Next' node refers to the first node that follows the main or master menu, which is usually the copying permissions, introduction, or first chapter.

Parts of a Master Menu
----------------------

A master menu is a detailed main menu listing all the nodes in a file.

A master menu is enclosed in @menu and @end menu commands and does not appear in the printed document.

Generally, a master menu is divided into parts.

  * The first part contains the major nodes in the Texinfo file: the nodes for the chapters, chapter-like sections, and the appendices.

  * The second part contains nodes for the indices.

  * The third and subsequent parts contain a listing of the other, lower level nodes, often ordered by chapter.  This way, rather than go through an intermediary menu, an inquirer can go directly to a particular node when searching for specific information.  These menu items are not required; add them if you think they are a convenience.  If you do use them, put @detailmenu before the first one, and @end detailmenu after the last; otherwise, makeinfo will get confused.

Each section in the menu can be introduced by a descriptive line.  So long as the line does not begin with an asterisk, it will not be treated as a menu entry.  (see Writing a Menu, for more information.)

For example, the master menu for this manual looks like the following (but has many more entries):

     @menu
     * Copying::             Texinfo is freely
                               redistributable.
     * Overview::            What is Texinfo?
     * Texinfo Mode::        Special features in GNU Emacs.
     ...
     ...

     * Command and Variable Index::
                             An entry for each @-command.
     * Concept Index::       An entry for each concept.

     @detailmenu
      --- The Detailed Node Listing ---

     Overview of Texinfo

     * Info Files::          What is an Info file?
     * Printed Manuals::     Characteristics of
                               a printed manual.
     ...
     ...

     Using Texinfo Mode

     * Info on a Region::    Formatting part of a file
                               for Info.
     ...
     ...
     @end detailmenu
     @end menu

Software Copying Permissions
============================

If the Texinfo file has a section containing the ``General Public License'' and the distribution information and a warranty disclaimer for the software that is documented, this section usually follows the `Top' node.  The General Public License is very important to Project GNU software.  It ensures that you and others will continue to have a right to use and share the software.

The copying and distribution information and the disclaimer are followed by an introduction or else by the first chapter of the manual.

Although an introduction is not a required part of a Texinfo file, it is very helpful.  Ideally, it should state clearly and concisely what the file is about and who would be interested in reading it.  In general, an introduction would follow the licensing and distribution information, although sometimes people put it earlier in the document. Usually, an introduction is put in an @unnumbered section. (see The @unnumbered and @appendix Commands.)

Ending a Texinfo File
*********************

The end of a Texinfo file should include the commands that create indices and generate detailed and summary tables of contents. And it must include the @bye command that marks the last line processed by TeX.

For example:

     @node    Concept Index,     , Variables Index, Top
     @c        node-name,    next, previous,        up
     @unnumbered Concept Index

     @printindex cp

     @contents
     @bye

Index Menus and Printing an Index
=================================

To print an index means to include it as part of a manual or Info file.  This does not happen automatically just because you use @cindex or other index-entry generating commands in the Texinfo file; those just cause the raw data for the index to be accumulated.  To generate an index, you must include the @printindex command at the place in the document where you want the index to appear.  Also, as part of the process of creating a printed manual, you must run a program called texindex (see Format/Print Hardcopy) to sort the raw data to produce a sorted index file.  The sorted index file is what is actually used to print the index.

Texinfo offers six different types of predefined index: the concept index, the function index, the variables index, the keystroke index, the program index, and the data type index (see Predefined Indices).  Each index type has a two-letter name: cp, fn, vr, ky, pg, and tp.  You may merge indices, or put them into separate sections (see Combining Indices); or you may define your own indices (see Defining New Indices).

The @printindex command takes a two-letter index name, reads the corresponding sorted index file and formats it appropriately into an index.

The @printindex command does not generate a chapter heading for the index.  Consequently, you should precede the @printindex command with a suitable section or chapter command (usually @unnumbered) to supply the chapter heading and put the index into the table of contents.  Precede the @unnumbered command with an @node line.

For example:

     @node Variable Index, Concept Index, Function Index, Top
     @comment    node-name,         next,       previous, up
     @unnumbered Variable Index

     @printindex vr

     @node     Concept Index,     , Variable Index, Top
     @comment      node-name, next,       previous, up
     @unnumbered Concept Index

     @printindex cp

     @summarycontents
     @contents
     @bye

(Readers often prefer that the concept index come last in a book, since that makes it easiest to find.)

Generating a Table of Contents
==============================

The @chapter, @section, and other structuring commands supply the information to make up a table of contents, but they do not cause an actual table to appear in the manual.  To do this, you must use the @contents and @summarycontents commands:

@contents
     Generate a table of contents in a printed manual, including all chapters, sections, subsections, etc., as well as appendices and unnumbered chapters.  (Headings generated by the @heading series of commands do not appear in the table of contents.)  The @contents command should be written on a line by itself.

@shortcontents
@summarycontents
     (@summarycontents is a synonym for @shortcontents; the two commands are exactly the same.)

     Generate a short or summary table of contents that lists only the chapters (and appendices and unnumbered chapters).  Omit sections, subsections and subsubsections.  Only a long manual needs a short table of contents in addition to the full table of contents.

     Write the @shortcontents command on a line by itself right before the @contents command.

The table of contents commands automatically generate a chapter-like heading at the top of the first table of contents page.  Write the table of contents commands at the very end of a Texinfo file, just before the @bye command, following any index sections---anything in the Texinfo file after the table of contents commands will be omitted from the table of contents.

When you print a manual with a table of contents, the table of contents are printed last and numbered with roman numerals.  You need to place those pages in their proper place, after the title page, yourself.  (This is the only collating you need to do for a printed manual.  The table of contents is printed last because it is generated after the rest of the manual is typeset.)

Here is an example of where to write table of contents commands:

     INDICES...
     @shortcontents
     @contents
     @bye

Since an Info file uses menus instead of tables of contents, the Info formatting commands ignore the @contents and @shortcontents commands.

@bye File Ending
================

An @bye command terminates TeX or Info formatting.  None of the formatting commands see any of the file following @bye. The @bye command should be on a line by itself.

If you wish, you may follow the @bye line with notes. These notes will not be formatted and will not appear in either Info or a printed manual; it is as if text after @bye were within @ignore ... @end ignore.  Also, you may follow the @bye line with a local variables list.  See Using Local Variables and the Compile Command, for more information.

Chapter Structuring
*******************

The chapter structuring commands divide a document into a hierarchy of chapters, sections, subsections, and subsubsections.  These commands generate large headings; they also provide information for the table of contents of a printed manual (see Generating a Table of Contents).

The chapter structuring commands do not create an Info node structure, so normally you should put an @node command immediately before each chapter structuring command (see Nodes).  The only time you are likely to use the chapter structuring commands without using the node structuring commands is if you are writing a document that contains no cross references and will never be transformed into Info format.

It is unlikely that you will ever write a Texinfo file that is intended only as an Info file and not as a printable document.  If you do, you might still use chapter structuring commands to create a heading at the top of each node---but you don't need to.

Tree Structure of Sections
==========================

A Texinfo file is usually structured like a book with chapters, sections, subsections, and the like.  This structure can be visualized as a tree (or rather as an upside-down tree) with the root at the top and the levels corresponding to chapters, sections, subsection, and subsubsections.

Here is a diagram that shows a Texinfo file with three chapters, each of which has two sections.

                               Top
                                |
              -------------------------------------
             |                  |                  |
          Chapter 1          Chapter 2          Chapter 3
             |                  |                  |
          --------           --------           --------
         |        |         |        |         |        |
      Section  Section   Section  Section   Section  Section
        1.1      1.2       2.1      2.2       3.1      3.2

In a Texinfo file that has this structure, the beginning of Chapter 2 looks like this:

     @node    Chapter 2,  Chapter 3, Chapter 1, top
     @chapter Chapter 2

The chapter structuring commands are described in the sections that follow; the @node and @menu commands are described in following chapters. (see Nodes, and see Menus.)

Types of Structuring Commands
=============================

The chapter structuring commands fall into four groups or series, each of which contains structuring commands corresponding to the hierarchical levels of chapters, sections, subsections, and subsubsections.

The four groups are the @chapter series, the @unnumbered series, the @appendix series, and the @heading series.

Each command produces titles that have a different appearance on the printed page or Info file; only some of the commands produce titles that are listed in the table of contents of a printed book or manual.

  * The @chapter and @appendix series of commands produce numbered or lettered entries both in the body of a printed work and in its table of contents.

  * The @unnumbered series of commands produce unnumbered entries both in the body of a printed work and in its table of contents.  The @top command, which has a special use, is a member of this series (see @top).

  * The @heading series of commands produce unnumbered headings that do not appear in a table of contents.  The heading commands never start a new page.

  * The @majorheading command produces results similar to using the @chapheading command but generates a larger vertical whitespace before the heading.

  * When an @setchapternewpage command says to do so, the @chapter, @unnumbered, and @appendix commands start new pages in the printed manual; the @heading commands do not.

Here are the four groups of chapter structuring commands:

                                                            No new pages
     Numbered       Unnumbered       Lettered and numbered  Unnumbered
     In contents    In contents          In contents        Not in contents

                    @top                                    @majorheading
     @chapter       @unnumbered          @appendix          @chapheading
     @section       @unnumberedsec       @appendixsec       @heading
     @subsection    @unnumberedsubsec    @appendixsubsec    @subheading
     @subsubsection @unnumberedsubsubsec @appendixsubsubsec @subsubheading

@top
====

The @top command is a special sectioning command that you use only after an @node Top line at the beginning of a Texinfo file. The @top command tells the makeinfo formatter which node is the `Top' node.  It has the same typesetting effect as @unnumbered (see @unnumbered (@appendix)). For detailed information, see The @top Command.

@chapter
========

@chapter identifies a chapter in the document.  Write the command at the beginning of a line and follow it on the same line by the title of the chapter.

For example, this chapter in this manual is entitled ``Chapter Structuring''; the @chapter line looks like this:

     @chapter Chapter Structuring

In TeX, the @chapter command creates a chapter in the document, specifying the chapter title.  The chapter is numbered automatically.

In Info, the @chapter command causes the title to appear on a line by itself, with a line of asterisks inserted underneath.  Thus, in Info, the above example produces the following output:

     Chapter Structuring
     *******************

Texinfo also provides a command @centerchap, which is analogous to @unnumbered, but centers its argument in the printed output. This kind of stylistic choice is not usually offered by Texinfo.

@unnumbered, @appendix
======================

Use the @unnumbered command to create a chapter that appears in a printed manual without chapter numbers of any kind.  Use the @appendix command to create an appendix in a printed manual that is labelled by letter instead of by number.

For Info file output, the @unnumbered and @appendix commands are equivalent to @chapter: the title is printed on a line by itself with a line of asterisks underneath.  (see @chapter.)

To create an appendix or an unnumbered chapter, write an @appendix or @unnumbered command at the beginning of a line and follow it on the same line by the title, as you would if you were creating a chapter.

@majorheading, @chapheading
===========================

The @majorheading and @chapheading commands put chapter-like headings in the body of a document.

However, neither command causes TeX to produce a numbered heading or an entry in the table of contents; and neither command causes TeX to start a new page in a printed manual.

In TeX, an @majorheading command generates a larger vertical whitespace before the heading than an @chapheading command but is otherwise the same.

In Info, the @majorheading and @chapheading commands are equivalent to @chapter: the title is printed on a line by itself with a line of asterisks underneath.  (see @chapter.)

@section
========

In a printed manual, an @section command identifies a numbered section within a chapter.  The section title appears in the table of contents.  In Info, an @section command provides a title for a segment of text, underlined with =.

This section is headed with an @section command and looks like this in the Texinfo file:

     @section @code{@@section}

To create a section, write the @section command at the beginning of a line and follow it on the same line by the section title.

Thus,

     @section This is a section

produces

     This is a section
     =================

in Info.

@unnumberedsec, @appendixsec, @heading
======================================

The @unnumberedsec, @appendixsec, and @heading commands are, respectively, the unnumbered, appendix-like, and heading-like equivalents of the @section command. (see @section.)

@unnumberedsec
     The @unnumberedsec command may be used within an unnumbered chapter or within a regular chapter or appendix to provide an unnumbered section.

@appendixsec
@appendixsection
     @appendixsection is a longer spelling of the @appendixsec command; the two are synonymous.

     Conventionally, the @appendixsec or @appendixsection command is used only within appendices.

@heading
     You may use the @heading command anywhere you wish for a section-style heading that will not appear in the table of contents.

The @subsection Command
=======================

Subsections are to sections as sections are to chapters. (see @section.)  In Info, subsection titles are underlined with -.  For example,

     @subsection This is a subsection

produces

     This is a subsection
     --------------------

In a printed manual, subsections are listed in the table of contents and are numbered three levels deep.

The @subsection-like Commands
=============================

The @unnumberedsubsec, @appendixsubsec, and @subheading commands are, respectively, the unnumbered, appendix-like, and heading-like equivalents of the @subsection command.  (see @subsection.)

In Info, the @subsection-like commands generate a title underlined with hyphens.  In a printed manual, an @subheading command produces a heading like that of a subsection except that it is not numbered and does not appear in the table of contents.  Similarly, an @unnumberedsubsec command produces an unnumbered heading like that of a subsection and an @appendixsubsec command produces a subsection-like heading labelled with a letter and numbers; both of these commands produce headings that appear in the table of contents.

The `subsub' Commands
=====================

The fourth and lowest level sectioning commands in Texinfo are the `subsub' commands.  They are:

@subsubsection
     Subsubsections are to subsections as subsections are to sections. (see @subsection.)  In a printed manual, subsubsection titles appear in the table of contents and are numbered four levels deep.

@unnumberedsubsubsec
     Unnumbered subsubsection titles appear in the table of contents of a printed manual, but lack numbers.  Otherwise, unnumbered subsubsections are the same as subsubsections.  In Info, unnumbered subsubsections look exactly like ordinary subsubsections.

@appendixsubsubsec
     Conventionally, appendix commands are used only for appendices and are lettered and numbered appropriately in a printed manual.  They also appear in the table of contents.  In Info, appendix subsubsections look exactly like ordinary subsubsections.

@subsubheading
     The @subsubheading command may be used anywhere that you need a small heading that will not appear in the table of contents.  In Info, subsubheadings look exactly like ordinary subsubsection headings.

In Info,  `subsub' titles are underlined with periods. For example,

     @subsubsection This is a subsubsection

produces

     This is a subsubsection
     .......................

@raisesections and @lowersections
=================================

The @raisesections and @lowersections commands raise and lower the hierarchical level of chapters, sections, subsections and the like.  The @raisesections command changes sections to chapters, subsections to sections, and so on.  The @lowersections command changes chapters to sections, sections to subsections, and so on.

An @lowersections command is useful if you wish to include text that is written as an outer or standalone Texinfo file in another Texinfo file as an inner, included file.  If you write the command at the beginning of the file, all your @chapter commands are formatted as if they were @section commands, all your @section command are formatted as if they were @subsection commands, and so on.

@raisesections raises a command one level in the chapter structuring hierarchy:

       Change           To

     @subsection     @section,
     @section        @chapter,
     @heading        @chapheading,
               etc.

@lowersections lowers a command one level in the chapter structuring hierarchy:

       Change           To

     @chapter        @section,
     @subsection     @subsubsection,
     @heading        @subheading,
               etc.

An @raisesections or @lowersections command changes only those structuring commands that follow the command in the Texinfo file. Write an @raisesections or @lowersections command on a line of its own.

An @lowersections command cancels an @raisesections command, and vice versa.  Typically, the commands are used like this:

     @lowersections
     @include somefile.texi
     @raisesections

Without the @raisesections, all the subsequent sections in your document will be lowered.

Repeated use of the commands continue to raise or lower the hierarchical level a step at a time.

An attempt to raise above `chapters' reproduces chapter commands; an attempt to lower below `subsubsections' reproduces subsubsection commands.

Nodes
*****

Nodes are the primary segments of a Texinfo file.  They do not themselves impose a hierarchic or any other kind of structure on a file. Nodes contain node pointers that name other nodes, and can contain menus which are lists of nodes.  In Info, the movement commands can carry you to a pointed-to node or to a node listed in a menu.  Node pointers and menus provide structure for Info files just as chapters, sections, subsections, and the like, provide structure for printed books.

Two Paths
=========

The node and menu commands and the chapter structuring commands are independent of each other:

  * In Info, node and menu commands provide structure.  The chapter structuring commands generate headings with different kinds of underlining---asterisks for chapters, hyphens for sections, and so on; they do nothing else.

  * In TeX, the chapter structuring commands generate chapter and section numbers and tables of contents.  The node and menu commands provide information for cross references; they do nothing else.

You can use node pointers and menus to structure an Info file any way you want; and you can write a Texinfo file so that its Info output has a different structure than its printed output.  However, most Texinfo files are written such that the structure for the Info output corresponds to the structure for the printed output.  It is not convenient to do otherwise.

Generally, printed output is structured in a tree-like hierarchy in which the chapters are the major limbs from which the sections branch out.  Similarly, node pointers and menus are organized to create a matching structure in the Info output.

Node and Menu Illustration
==========================

Here is a copy of the diagram shown earlier that illustrates a Texinfo file with three chapters, each of which contains two sections.

Note that the ``root'' is at the top of the diagram and the ``leaves'' are at the bottom.  This is how such a diagram is drawn conventionally; it illustrates an upside-down tree.  For this reason, the root node is called the `Top' node, and `Up' node pointers carry you closer to the root.

                               Top
                                |
              -------------------------------------
             |                  |                  |
          Chapter 1          Chapter 2          Chapter 3
             |                  |                  |
          --------           --------           --------
         |        |         |        |         |        |
      Section  Section   Section  Section   Section  Section
        1.1      1.2       2.1      2.2       3.1      3.2

Write the beginning of the node for Chapter 2 like this:

     @node     Chapter 2,  Chapter 3, Chapter 1, top
     @comment  node-name,  next,      previous,  up

This @node line says that the name of this node is ``Chapter 2'', the name of the `Next' node is ``Chapter 3'', the name of the `Previous' node is ``Chapter 1'', and the name of the `Up' node is ``Top''.

     Please Note: `Next' refers to the next node at the same hierarchical level in the manual, not necessarily to the next node within the Texinfo file.  In the Texinfo file, the subsequent node may be at a lower level---a section-level node may follow a chapter-level node, and a subsection-level node may follow a section-level node. `Next' and `Previous' refer to nodes at the same hierarchical level.  (The `Top' node contains the exception to this rule.  Since the `Top' node is the only node at that level, `Next' refers to the first following node, which is almost always a chapter or chapter-level node.)

To go to Sections 2.1 and 2.2 using Info, you need a menu inside Chapter 2.  (see Menus.)  You would write the menu just before the beginning of Section 2.1, like this:

         @menu
         * Sect. 2.1::    Description of this section.
         * Sect. 2.2::
         @end menu

Write the node for Sect. 2.1 like this:

         @node     Sect. 2.1, Sect. 2.2, Chapter 2, Chapter 2
         @comment  node-name, next,      previous,  up

In Info format, the `Next' and `Previous' pointers of a node usually lead to other nodes at the same level---from chapter to chapter or from section to section (sometimes, as shown, the `Previous' pointer points up); an `Up' pointer usually leads to a node at the level above (closer to the `Top' node); and a `Menu' leads to nodes at a level below (closer to `leaves').  (A cross reference can point to a node at any level; see Cross References.)

Usually, an @node command and a chapter structuring command are used in sequence, along with indexing commands.  (You may follow the @node line with a comment line that reminds you which pointer is which.)

Here is the beginning of the chapter in this manual called ``Ending a Texinfo File''.  This shows an @node line followed by a comment line, an @chapter line, and then by indexing lines.

     @node    Ending a File, Structuring, Beginning a File, Top
     @comment node-name,     next,        previous,         up
     @chapter Ending a Texinfo File
     @cindex Ending a Texinfo file
     @cindex Texinfo file ending
     @cindex File ending

The @node Command
=================

A node is a segment of text that begins at an @node command and continues until the next @node command.  The definition of node is different from that for chapter or section.  A chapter may contain sections and a section may contain subsections; but a node cannot contain subnodes; the text of a node continues only until the next @node command in the file.  A node usually contains only one chapter structuring command, the one that follows the @node line.  On the other hand, in printed output nodes are used only for cross references, so a chapter or section may contain any number of nodes.  Indeed, a chapter usually contains several nodes, one for each section, subsection, and subsubsection.

To create a node, write an @node command at the beginning of a line, and follow it with four arguments, separated by commas, on the rest of the same line.  These arguments are the name of the node, and the names of the `Next', `Previous', and `Up' pointers, in that order. You may insert spaces before each pointer if you wish; the spaces are ignored.  You must write the name of the node, and the names of the `Next', `Previous', and `Up' pointers, all on the same line.  Otherwise, the formatters fail.  (see info, for more information about nodes in Info.)

Usually, you write one of the chapter-structuring command lines immediately after an @node line---for example, an @section or @subsection line.  (see Types of Structuring Commands.)

     Please note: The GNU Emacs Texinfo mode updating commands work only with Texinfo files in which @node lines are followed by chapter structuring lines.  See Updating Requirements.

TeX uses @node lines to identify the names to use for cross references.  For this reason, you must write @node lines in a Texinfo file that you intend to format for printing, even if you do not intend to format it for Info.  (Cross references, such as the one at the end of this sentence, are made with @xref and its related commands; see Cross References.)

Choosing Node and Pointer Names
-------------------------------

The name of a node identifies the node.  The pointers enable you to reach other nodes and consist of the names of those nodes.

Normally, a node's `Up' pointer contains the name of the node whose menu mentions that node.  The node's `Next' pointer contains the name of the node that follows that node in that menu and its `Previous' pointer contains the name of the node that precedes it in that menu.  When a node's `Previous' node is the same as its `Up' node, both node pointers name the same node.

Usually, the first node of a Texinfo file is the `Top' node, and its `Up' and `Previous' pointers point to the dir file, which contains the main menu for all of Info.

The `Top' node itself contains the main or master menu for the manual. Also, it is helpful to include a brief description of the manual in the `Top' node.  See First Node, for information on how to write the first node of a Texinfo file.

How to Write an @node Line
--------------------------

The easiest way to write an @node line is to write @node at the beginning of a line and then the name of the node, like this:

     @node NODE-NAME

If you are using GNU Emacs, you can use the update node commands provided by Texinfo mode to insert the names of the pointers; or you can leave the pointers out of the Texinfo file and let makeinfo insert node pointers into the Info file it creates.  (see Texinfo Mode, and makeinfo Pointer Creation.)

Alternatively, you can insert the `Next', `Previous', and `Up' pointers yourself.  If you do this, you may find it helpful to use the Texinfo mode keyboard command C-c C-c n.  This command inserts @node and a comment line listing the names of the pointers in their proper order.  The comment line helps you keep track of which arguments are for which pointers.  This comment line is especially useful if you are not familiar with Texinfo.

The template for a node line with `Next', `Previous', and `Up' pointers looks like this:

     @node NODE-NAME, NEXT, PREVIOUS, UP

If you wish, you can ignore @node lines altogether in your first draft and then use the texinfo-insert-node-lines command to create @node lines for you.  However, we do not recommend this practice.  It is better to name the node itself at the same time that you write a segment so you can easily make cross references.  A large number of cross references are an especially important feature of a good Info file.

After you have inserted an @node line, you should immediately write an @-command for the chapter or section and insert its name. Next (and this is important!), put in several index entries.  Usually, you will find at least two and often as many as four or five ways of referring to the node in the index.  Use them all.  This will make it much easier for people to find the node.

@node Line Tips
---------------

Here are three suggestions:

  * Try to pick node names that are informative but short.

     In the Info file, the file name, node name, and pointer names are all inserted on one line, which may run into the right edge of the window. (This does not cause a problem with Info, but is ugly.)

  * Try to pick node names that differ from each other near the beginnings of their names.  This way, it is easy to use automatic name completion in Info.

  * By convention, node names are capitalized just as they would be for section or chapter titles---initial and significant words are capitalized; others are not.

@node Line Requirements
-----------------------

Here are several requirements for @node lines:

  * All the node names for a single Info file must be unique.

     Duplicates confuse the Info movement commands.  This means, for example, that if you end every chapter with a summary, you must name each summary node differently.  You cannot just call each one ``Summary''.  You may, however, duplicate the titles of chapters, sections, and the like.  Thus you can end each chapter in a book with a section called ``Summary'', so long as the node names for those sections are all different.

  * A pointer name must be the name of a node.

     The node to which a pointer points may come before or after the node containing the pointer.

  * You cannot use any of the Texinfo @-commands in a node name; @-commands confuse Info.

     Thus, the beginning of the section called @chapter looks like this:

          @node  chapter, unnumbered & appendix, makeinfo top, Structuring
          @comment  node-name,  next,  previous,  up
          @section @code{@@chapter}
          @findex chapter

  * You cannot use commas or apostrophes within a node name; these confuse TeX or the Info formatters.

     For example, the following is a section title:

          @code{@@unnumberedsec}, @code{@@appendixsec}, @code{@@heading}

     The corresponding node name is:

          unnumberedsec appendixsec heading

  * Case is significant.

The First Node
--------------

The first node of a Texinfo file is the Top node, except in an included file (see Include Files).  The Top node contains the main or master menu for the document, and a short summary of the document (see Top Node Summary).

The Top node (which must be named top or Top) should have as its `Up' node the name of a node in another file, where there is a menu that leads to this file.  Specify the file name in parentheses.  If the file is to be installed directly in the Info directory file, use (dir) as the parent of the Top node; this is short for (dir)top, and specifies the Top node in the dir file, which contains the main menu for the Info system as a whole.  For example, the @node Top line of this manual looks like this:

     @node Top, Copying, , (dir)

(You can use the Texinfo updating commands or the makeinfo utility to insert these pointers automatically.)

Do not define the `Previous' node of the Top node to be (dir), as it causes confusing behavior for users: if you are in the Top node and hits DEL to go backwards, you wind up in the middle of the some other entry in the dir file, which has nothing to do with what you were reading.

See Install an Info File, for more information about installing an Info file in the info directory.

The @top Sectioning Command
---------------------------

A special sectioning command, @top, has been created for use with the @node Top line.  The @top sectioning command tells makeinfo that it marks the `Top' node in the file.  It provides the information that makeinfo needs to insert node pointers automatically.  Write the @top command at the beginning of the line immediately following the @node Top line.  Write the title on the remaining part of the same line as the @top command.

In Info, the @top sectioning command causes the title to appear on a line by itself, with a line of asterisks inserted underneath.

In TeX and texinfo-format-buffer, the @top sectioning command is merely a synonym for @unnumbered. Neither of these formatters require an @top command, and do nothing special with it.  You can use @chapter or @unnumbered after the @node Top line when you use these formatters.  Also, you can use @chapter or @unnumbered when you use the Texinfo updating commands to create or update pointers and menus.

The `Top' Node Summary
----------------------

You can help readers by writing a summary in the `Top' node, after the @top line, before the main or master menu.  The summary should briefly describe the document.  In Info, this summary will appear just before the master menu.  In a printed manual, this summary will appear on a page of its own.

If you do not want the summary to appear on a page of its own in a printed manual, you can enclose the whole of the `Top' node, including the @node Top line and the @top sectioning command line or other sectioning command line between @ifinfo and @end ifinfo.  This prevents any of the text from appearing in the printed output. (see Conditionally Visible Text).  You can repeat the brief description from the `Top' node within @iftex ... @end iftex at the beginning of the first chapter, for those who read the printed manual.  This saves paper and may look neater.

You should write the version number of the program to which the manual applies in the summary.  This helps the reader keep track of which manual is for which version of the program.  If the manual changes more frequently than the program or is independent of it, you should also include an edition number for the manual.  (The title page should also contain this information: see @titlepage.)

Creating Pointers with makeinfo
===============================

The makeinfo program has a feature for automatically creating node pointers for a hierarchically organized file that lacks them.

When you take advantage of this feature, you do not need to write the `Next', `Previous', and `Up' pointers after the name of a node. However, you must write a sectioning command, such as @chapter or @section, on the line immediately following each truncated @node line.  You cannot write a comment line after a node line; the section line must follow it immediately.

In addition, you must follow the `Top' @node line with a line beginning with @top to mark the `Top' node in the file. See @top.

Finally, you must write the name of each node (except for the `Top' node) in a menu that is one or more hierarchical levels above the node's hierarchical level.

This node pointer insertion feature in makeinfo is an alternative to the menu and pointer creation and update commands in Texinfo mode.  (see Updating Nodes and Menus.)  It is especially helpful to people who do not use GNU Emacs for writing Texinfo documents.

Menus
*****

Menus contain pointers to subordinate nodes. (Menus can carry you to any node, regardless of the hierarchical structure; even to nodes in a different Info file.  However, the GNU Emacs Texinfo mode updating commands work only to create menus of subordinate nodes. Conventionally, cross references are used to refer to other nodes.) In Info, you use menus to go to such nodes.  Menus have no effect in printed manuals and do not appear in them.

By convention, a menu is put at the end of a node since a reader who uses the menu may not see text that follows it.

A node that has a menu should not contain much text.  If you have a lot of text and a menu, move most of the text into a new subnode---all but a few lines.

Menus Need Short Nodes
======================

A reader can easily see a menu that is close to the beginning of the node.  The node should be short.  As a practical matter, you should locate a menu within 20 lines of the beginning of the node. Otherwise, a reader with a terminal that displays only a few lines may miss the menu and its associated text.

The short text before a menu may look awkward in a printed manual.  To avoid this, you can write a menu near the beginning of its node and follow the menu by an @node line, and then an @heading line located within @ifinfo and @end ifinfo.  This way, the menu, @node line, and title appear only in the Info file, not the printed document.

For example, the preceding two paragraphs follow an Info-only menu, @node line, and heading, and look like this:

     @menu
     * Menu Location::             Put a menu in a short node.
     * Writing a Menu::            What is a menu?
     * Menu Parts::                A menu entry has three parts.
     * Less Cluttered Menu Entry:: Two part menu entry.
     * Menu Example::              Two and three part entries.
     * Other Info Files::          How to refer to a different
                                     Info file.
     @end menu

     @node Menu Location, Writing a Menu, , Menus
     @ifinfo
     @heading Menus Need Short Nodes
     @end ifinfo

The Texinfo file for this document contains more than a dozen examples of this procedure.  One is at the beginning of this chapter; another is at the beginning of the ``Cross References'' chapter.

Writing a Menu
==============

A menu consists of an @menu command on a line by itself followed by menu entry lines or menu comment lines and then by an @end menu command on a line by itself.

A menu looks like this:

     @menu
     Larger Units of Text

     * Files::                       All about handling files.
     * Multiples: Buffers.           Multiple buffers; editing
                                       several files at once.
     @end menu

In a menu, every line that begins with an *  is a menu entry.  (Note the space after the asterisk.)  A line that does not start with an *  may also appear in a menu.  Such a line is not a menu entry but is a menu comment line that appears in the Info file.  In the example above, the line Larger Units of Text is a menu comment line; the two lines starting with * are menu entries.

The Parts of a Menu
===================

A menu entry has three parts, only the second of which is required:

 1. The menu entry name (optional).

 2. The name of the node (required).

 3. A description of the item (optional).

The template for a menu entry looks like this:

     * MENU-ENTRY-NAME: NODE-NAME.   DESCRIPTION

Follow the menu entry name with a single colon and follow the node name with tab, comma, period, or newline.

In Info, a user selects a node with the m (Info-menu) command.  The menu entry name is what the user types after the m command.

The third part of a menu entry is a descriptive phrase or sentence. Menu entry names and node names are often short; the description explains to the reader what the node is about.  A useful description complements the node name rather than repeats it.  The description, which is optional, can spread over two or more lines; if it does, some authors prefer to indent the second line while others prefer to align it with the first (and all others).  It's up to you.

Less Cluttered Menu Entry
=========================

When the menu entry name and node name are the same, you can write the name immediately after the asterisk and space at the beginning of the line and follow the name with two colons.

For example, write

     * Name::                                    DESCRIPTION

instead of

     * Name: Name.                               DESCRIPTION

You should use the node name for the menu entry name whenever possible, since it reduces visual clutter in the menu.

A Menu Example
==============

A menu looks like this in Texinfo:

     @menu
     * menu entry name: Node name.   A short description.
     * Node name::                   This form is preferred.
     @end menu

This produces:

     * menu:

     * menu entry name: Node name.   A short description.
     * Node name::                   This form is preferred.

Here is an example as you might see it in a Texinfo file:

     @menu
     Larger Units of Text

     * Files::                       All about handling files.
     * Multiples: Buffers.           Multiple buffers; editing
                                       several files at once.
     @end menu

This produces:

     * menu:
     Larger Units of Text

     * Files::                       All about handling files.
     * Multiples: Buffers.           Multiple buffers; editing
                                       several files at once.

In this example, the menu has two entries.  Files is both a menu entry name and the name of the node referred to by that name. Multiples is the menu entry name; it refers to the node named Buffers. The line Larger Units of Text is a comment; it appears in the menu, but is not an entry.

Since no file name is specified with either Files or Buffers, they must be the names of nodes in the same Info file (see Referring to Other Info Files).

Referring to Other Info Files
=============================

You can create a menu entry that enables a reader in Info to go to a node in another Info file by writing the file name in parentheses just before the node name.  In this case, you should use the three-part menu entry format, which saves the reader from having to type the file name.

The format looks like this:

     @menu
     * FIRST-ENTRY-NAME:(FILENAME)NODENAME.     DESCRIPTION
     * SECOND-ENTRY-NAME:(FILENAME)SECOND-NODE. DESCRIPTION
     @end menu

For example, to refer directly to the Outlining and Rebinding nodes in the Emacs Manual, you would write a menu like this:

     @menu
     * Outlining: (emacs)Outline Mode. The major mode for
                                       editing outlines.
     * Rebinding: (emacs)Rebinding.    How to redefine the
                                       meaning of a key.
     @end menu

If you do not list the node name, but only name the file, then Info presumes that you are referring to the `Top' node.

The dir file that contains the main menu for Info has menu entries that list only file names.  These take you directly to the `Top' nodes of each Info document.  (see Install an Info File.)

For example:

     * Info: (info).         Documentation browsing system.
     * Emacs: (emacs).       The extensible, self-documenting
                             text editor.

(The dir top level directory for the Info system is an Info file, not a Texinfo file, but a menu entry looks the same in both types of file.)

Note that the GNU Emacs Texinfo mode menu updating commands only work with nodes within the current buffer, so you cannot use them to create menus that refer to other files.  You must write such menus by hand.

Cross References
****************

Cross references are used to refer the reader to other parts of the same or different Texinfo files.  In Texinfo, nodes are the places to which cross references can refer.

What References Are For
=======================

Often, but not always, a printed document should be designed so that it can be read sequentially.  People tire of flipping back and forth to find information that should be presented to them as they need it.

However, in any document, some information will be too detailed for the current context, or incidental to it; use cross references to provide access to such information.  Also, an on-line help system or a reference manual is not like a novel; few read such documents in sequence from beginning to end.  Instead, people look up what they need.  For this reason, such creations should contain many cross references to help readers find other information that they may not have read.

In a printed manual, a cross reference results in a page reference, unless it is to another manual altogether, in which case the cross reference names that manual.

In Info, a cross reference results in an entry that you can follow using the Info f command.  (see Some advanced Info commands (info).)

The various cross reference commands use nodes to define cross reference locations.  This is evident in Info, in which a cross reference takes you to the specified node.  TeX also uses nodes to define cross reference locations, but the action is less obvious.  When TeX generates a DVI file, it records nodes' page numbers and uses the page numbers in making references.  Thus, if you are writing a manual that will only be printed, and will not be used on-line, you must nonetheless write @node lines to name the places to which you make cross references.

Different Cross Reference Commands
==================================

There are four different cross reference commands:

@xref
     Used to start a sentence in the printed manual saying `See ...' or an Info cross-reference saying *Note NAME: NODE..

@ref
     Used within or, more often, at the end of a sentence; same as @xref for Info; produces just the reference in the printed manual without a preceding `See'.

@pxref
     Used within parentheses to make a reference that suits both an Info file and a printed book.  Starts with a lower case `see' within the printed manual. (p is for `parenthesis'.)

@inforef
     Used to make a reference to an Info file for which there is no printed manual.

(The @cite command is used to make references to books and manuals for which there is no corresponding Info file and, therefore, no node to which to point.   See @cite.)

Parts of a Cross Reference
==========================

A cross reference command requires only one argument, which is the name of the node to which it refers.  But a cross reference command may contain up to four additional arguments.  By using these arguments, you can provide a cross reference name for Info, a topic description or section title for the printed output, the name of a different Info file, and the name of a different printed manual.

Here is a simple cross reference example:

     @xref{Node name}.

which produces

     *Note Node name::.

and

     See Section NNN [Node name], page PPP.

Here is an example of a full five-part cross reference:

     @xref{Node name, Cross Reference Name, Particular Topic,
     info-file-name, A Printed Manual}, for details.

which produces

     *Note Cross Reference Name: (info-file-name)Node name,
     for details.

in Info and

     See section ``Particular Topic'' in A Printed Manual, for details.

in a printed book.

The five possible arguments for a cross reference are:

 1. The node name (required).  This is the node to which the cross reference takes you.  In a printed document, the location of the node provides the page reference only for references within the same document.

 2. The cross reference name for the Info reference, if it is to be different from the node name.  If you include this argument, it becomes the first part of the cross reference.  It is usually omitted.

 3. A topic description or section name.  Often, this is the title of the section.  This is used as the name of the reference in the printed manual.  If omitted, the node name is used.

 4. The name of the Info file in which the reference is located, if it is different from the current file.  You need not include any .info suffix on the file name, since Info readers try appending it automatically.

 5. The name of a printed manual from a different Texinfo file.

The template for a full five argument cross reference looks like this:

     @xref{NODE-NAME, CROSS-REFERENCE-NAME, TITLE-OR-TOPIC,
     INFO-FILE-NAME, PRINTED-MANUAL-TITLE}.

Cross references with one, two, three, four, and five arguments are described separately following the description of @xref.

Write a node name in a cross reference in exactly the same way as in the @node line, including the same capitalization; otherwise, the formatters may not find the reference.

You can write cross reference commands within a paragraph, but note how Info and TeX format the output of each of the various commands: write @xref at the beginning of a sentence; write @pxref only within parentheses, and so on.

@xref
=====

The @xref command generates a cross reference for the beginning of a sentence.  The Info formatting commands convert it into an Info cross reference, which the Info f command can use to bring you directly to another node.  The TeX typesetting commands convert it into a page reference, or a reference to another book or manual.

What a Reference Looks Like and Requires
----------------------------------------

Most often, an Info cross reference looks like this:

     *Note NODE-NAME::.

or like this

     *Note CROSS-REFERENCE-NAME: NODE-NAME.

In TeX, a cross reference looks like this:

     See Section SECTION-NUMBER [NODE-NAME], page PAGE.

or like this

     See Section SECTION-NUMBER [TITLE-OR-TOPIC], page PAGE.

The @xref command does not generate a period or comma to end the cross reference in either the Info file or the printed output. You must write that period or comma yourself; otherwise, Info will not recognize the end of the reference.  (The @pxref command works differently.  See @pxref.)

     Please note: A period or comma must follow the closing brace of an @xref.  It is required to terminate the cross reference.  This period or comma will appear in the output, both in the Info file and in the printed manual.

@xref must refer to an Info node by name.  Use @node to define the node (see Writing a Node).

@xref is followed by several arguments inside braces, separated by commas.  Whitespace before and after these commas is ignored.

A cross reference requires only the name of a node; but it may contain up to four additional arguments.  Each of these variations produces a cross reference that looks somewhat different.

     Please note: Commas separate arguments in a cross reference; avoid including them in the title or other part lest the formatters mistake them for separators.

@xref with One Argument
-----------------------

The simplest form of @xref takes one argument, the name of another node in the same Info file.    The Info formatters produce output that the Info readers can use to jump to the reference; TeX produces output that specifies the page and section number for you.

For example,

     @xref{Tropical Storms}.

produces

     *Note Tropical Storms::.

and

     See Section 3.1 [Tropical Storms], page 24.

(Note that in the preceding example the closing brace is followed by a period.)

You can write a clause after the cross reference, like this:

     @xref{Tropical Storms}, for more info.

which produces

     *Note Tropical Storms::, for more info.

     See Section 3.1 [Tropical Storms], page 24, for more info.

(Note that in the preceding example the closing brace is followed by a comma, and then by the clause, which is followed by a period.)

@xref with Two Arguments
------------------------

With two arguments, the second is used as the name of the Info cross reference, while the first is still the name of the node to which the cross reference points.

The template is like this:

     @xref{NODE-NAME, CROSS-REFERENCE-NAME}.

For example,

     @xref{Electrical Effects, Lightning}.

produces:

     *Note Lightning: Electrical Effects.

and

     See Section 5.2 [Electrical Effects], page 57.

(Note that in the preceding example the closing brace is followed by a period; and that the node name is printed, not the cross reference name.)

You can write a clause after the cross reference, like this:

     @xref{Electrical Effects, Lightning}, for more info.

which produces

     *Note Lightning: Electrical Effects, for more info.

and

     See Section 5.2 [Electrical Effects], page 57, for more info.

(Note that in the preceding example the closing brace is followed by a comma, and then by the clause, which is followed by a period.)

@xref with Three Arguments
--------------------------

A third argument replaces the node name in the TeX output.  The third argument should be the name of the section in the printed output, or else state the topic discussed by that section.  Often, you will want to use initial upper case letters so it will be easier to read when the reference is printed.  Use a third argument when the node name is unsuitable because of syntax or meaning.

Remember to avoid placing a comma within the title or topic section of a cross reference, or within any other section.  The formatters divide cross references into arguments according to the commas; a comma within a title or other section will divide it into two arguments.  In a reference, you need to write a title such as ``Clouds, Mist, and Fog'' without the commas.

Also, remember to write a comma or period after the closing brace of a @xref to terminate the cross reference.  In the following examples, a clause follows a terminating comma.

The template is like this:

     @xref{NODE-NAME, CROSS-REFERENCE-NAME, TITLE-OR-TOPIC}.

For example,

     @xref{Electrical Effects, Lightning, Thunder and Lightning},
     for details.

produces

     *Note Lightning: Electrical Effects, for details.

and

     See Section 5.2 [Thunder and Lightning], page 57, for details.

If a third argument is given and the second one is empty, then the third argument serves both.  (Note how two commas, side by side, mark the empty second argument.)

     @xref{Electrical Effects, , Thunder and Lightning},
     for details.

produces

     *Note Thunder and Lightning: Electrical Effects, for details.

and

     See Section 5.2 [Thunder and Lightning], page 57, for details.

As a practical matter, it is often best to write cross references with just the first argument if the node name and the section title are the same, and with the first and third arguments if the node name and title are different.

Here are several examples from The GNU Awk User's Guide:

     @xref{Sample Program}.
     @xref{Glossary}.
     @xref{Case-sensitivity, ,Case-sensitivity in Matching}.
     @xref{Close Output, , Closing Output Files and Pipes},
        for more information.
     @xref{Regexp, , Regular Expressions as Patterns}.

@xref with Four and Five Arguments
----------------------------------

In a cross reference, a fourth argument specifies the name of another Info file, different from the file in which the reference appears, and a fifth argument specifies its title as a printed manual.

Remember that a comma or period must follow the closing brace of an @xref command to terminate the cross reference.  In the following examples, a clause follows a terminating comma.

The template is:

     @xref{NODE-NAME, CROSS-REFERENCE-NAME, TITLE-OR-TOPIC,
     INFO-FILE-NAME, PRINTED-MANUAL-TITLE}.

For example,

     @xref{Electrical Effects, Lightning, Thunder and Lightning,
     weather, An Introduction to Meteorology}, for details.

produces

     *Note Lightning: (weather)Electrical Effects, for details.

The name of the Info file is enclosed in parentheses and precedes the name of the node.

In a printed manual, the reference looks like this:

     See section ``Thunder and Lightning'' in An Introduction to Meteorology, for details.

The title of the printed manual is typeset in italics; and the reference lacks a page number since TeX cannot know to which page a reference refers when that reference is to another manual.

Often, you will leave out the second argument when you use the long version of @xref.  In this case, the third argument, the topic description, will be used as the cross reference name in Info.

The template looks like this:

     @xref{NODE-NAME, , TITLE-OR-TOPIC, INFO-FILE-NAME,
     PRINTED-MANUAL-TITLE}, for details.

which produces

     *Note TITLE-OR-TOPIC: (INFO-FILE-NAME)NODE-NAME, for details.

and

     See section TITLE-OR-TOPIC in PRINTED-MANUAL-TITLE, for details.

For example,

     @xref{Electrical Effects, , Thunder and Lightning,
     weather, An Introduction to Meteorology}, for details.

produces

     *Note Thunder and Lightning: (weather)Electrical Effects,
     for details.

and

     See section ``Thunder and Lightning'' in An Introduction to Meteorology, for details.

On rare occasions, you may want to refer to another Info file that is within a single printed manual---when multiple Texinfo files are incorporated into the same TeX run but make separate Info files. In this case, you need to specify only the fourth argument, and not the fifth.

Naming a `Top' Node
===================

In a cross reference, you must always name a node.  This means that in order to refer to a whole manual, you must identify the `Top' node by writing it as the first argument to the @xref command.  (This is different from the way you write a menu entry; see Referring to Other Info Files.)  At the same time, to provide a meaningful section topic or title in the printed cross reference (instead of the word `Top'), you must write an appropriate entry for the third argument to the @xref command.

Thus, to make a cross reference to The GNU Make Manual, write:

     @xref{Top, , Overview, make, The GNU Make Manual}.

which produces

     *Note Overview: (make)Top.

and

     See section ``Overview'' in The GNU Make Manual.

In this example, Top is the name of the first node, and Overview is the name of the first section of the manual.

@ref
====

@ref is nearly the same as @xref except that it does not generate a `See' in the printed output, just the reference itself. This makes it useful as the last part of a sentence.

For example,

     For more information, see @ref{Hurricanes}.

produces

     For more information, see *Note Hurricanes.

and

     For more information, see Section 8.2 [Hurricanes], page 123.

The @ref command sometimes leads writers to express themselves in a manner that is suitable for a printed manual but looks awkward in the Info format.  Bear in mind that your audience will be using both the printed and the Info format.

For example,

     Sea surges are described in @ref{Hurricanes}.

produces

     Sea surges are described in Section 6.7 [Hurricanes], page 72.

in a printed document, and the following in Info:

     Sea surges are described in *Note Hurricanes::.

     Caution: You must write a period or comma immediately after an @ref command with two or more arguments.  Otherwise, Info will not find the end of the cross reference entry and its attempt to follow the cross reference will fail.  As a general rule, you should write a period or comma after every @ref command. This looks best in both the printed and the Info output.

@pxref
======

The parenthetical reference command, @pxref, is nearly the same as @xref, but you use it only inside parentheses and you do not type a comma or period after the command's closing brace.  The command differs from @xref in two ways:

 1. TeX typesets the reference for the printed manual with a lower case `see' rather than an upper case `See'.

 2. The Info formatting commands automatically end the reference with a closing colon or period.

Because one type of formatting automatically inserts closing punctuation and the other does not, you should use @pxref only inside parentheses as part of another sentence.  Also, you yourself should not insert punctuation after the reference, as you do with @xref.

@pxref is designed so that the output looks right and works right between parentheses both in printed output and in an Info file. In a printed manual, a closing comma or period should not follow a cross reference within parentheses; such punctuation is wrong.  But in an Info file, suitable closing punctuation must follow the cross reference so Info can recognize its end.  @pxref spares you the need to use complicated methods to put a terminator into one form of the output and not the other.

With one argument, a parenthetical cross reference looks like this:

     ... storms cause flooding (@pxref{Hurricanes}) ...

which produces

     ... storms cause flooding (*Note Hurricanes::) ...

and

     ... storms cause flooding (see Section 6.7 [Hurricanes], page 72) ...

With two arguments, a parenthetical cross reference has this template:

     ... (@pxref{NODE-NAME, CROSS-REFERENCE-NAME}) ...

which produces

     ... (*Note CROSS-REFERENCE-NAME: NODE-NAME.) ...

and

     ... (see Section NNN [NODE-NAME], page PPP) ...

@pxref can be used with up to five arguments just like @xref (see @xref).

     Please note: Use @pxref only as a parenthetical reference.  Do not try to use @pxref as a clause in a sentence. It will look bad in either the Info file, the printed output, or both.

     Also, parenthetical cross references look best at the ends of sentences. Although you may write them in the middle of a sentence, that location breaks up the flow of text.

@inforef
========

@inforef is used for cross references to Info files for which there are no printed manuals.  Even in a printed manual, @inforef generates a reference directing the user to look in an Info file.

The command takes either two or three arguments, in the following order:

 1. The node name.

 2. The cross reference name (optional).

 3. The Info file name.

Separate the arguments with commas, as with @xref.  Also, you must terminate the reference with a comma or period after the }, as you do with @xref.

The template is:

     @inforef{NODE-NAME, CROSS-REFERENCE-NAME, INFO-FILE-NAME},

Thus,

     @inforef{Expert, Advanced Info commands, info},
     for more information.

produces

     *Note Advanced Info commands: (info)Expert,
     for more information.

and

     See Info file info, node Expert, for more information.

Similarly,

     @inforef{Expert, , info}, for more information.

produces

     *Note (info)Expert::, for more information.

and

     See Info file info, node Expert, for more information.

The converse of @inforef is @cite, which is used to refer to printed works for which no Info form exists.  See @cite.

@uref{URL[, DISPLAYED-TEXT]}
============================

@uref produces a reference to a uniform resource locator (URL). It takes one mandatory argument, the URL, and one optional argument, the text to display (the default is the URL itself).  In HTML output, @uref produces a link you can follow.  For example:

     The official GNU ftp site is
     @uref{ftp://ftp.gnu.ai.mit.edu/pub/gnu}

produces (in text):

     The official GNU ftp site is
     ftp://ftp.gnu.ai.mit.edu/pub/gnu

whereas

     The official
     @uref{ftp://ftp.gnu.ai.mit.edu/pub/gnu,
       GNU ftp site} holds programs and texts.

produces (in text):

     The official GNU ftp site (ftp://ftp.gnu.ai.mit.edu/pub/gnu) holds
     programs and texts.

and (in HTML):

     The official <A HREF="ftp://ftp.gnu.ai.mit.edu/pub/gnu">GNU ftp
     site</A> holds programs and texts.

To merely indicate a URL, use @url (see @url).

Marking Words and Phrases
*************************

In Texinfo, you can mark words and phrases in a variety of ways. The Texinfo formatters use this information to determine how to highlight the text. You can specify, for example, whether a word or phrase is a defining occurrence, a metasyntactic variable, or a symbol used in a program.  Also, you can emphasize text.

Indicating Definitions, Commands, etc.
======================================

Texinfo has commands for indicating just what kind of object a piece of text refers to.  For example, metasyntactic variables are marked by @var, and code by @code.  Since the pieces of text are labelled by commands that tell what kind of object they are, it is easy to change the way the Texinfo formatters prepare such text.  (Texinfo is an intentional formatting language rather than a typesetting formatting language.)

For example, in a printed manual, code is usually illustrated in a typewriter font; @code tells TeX to typeset this text in this font.  But it would be easy to change the way TeX highlights code to use another font, and this change would not effect how keystroke examples are highlighted.  If straight typesetting commands were used in the body of the file and you wanted to make a change, you would need to check every single occurrence to make sure that you were changing code and not something else that should not be changed.

Highlighting Commands are Useful
--------------------------------

The highlighting commands can be used to generate useful information from the file, such as lists of functions or file names.  It is possible, for example, to write a program in Emacs Lisp (or a keyboard macro) to insert an index entry after every paragraph that contains words or phrases marked by a specified command.  You could do this to construct an index of functions if you had not already made the entries.

The commands serve a variety of purposes:

@code{SAMPLE-CODE}
     Indicate text that is a literal example of a piece of a program.

@kbd{KEYBOARD-CHARACTERS}
     Indicate keyboard input.

@key{KEY-NAME}
     Indicate the conventional name for a key on a keyboard.

@samp{TEXT}
     Indicate text that is a literal example of a sequence of characters.

@var{METASYNTACTIC-VARIABLE}
     Indicate a metasyntactic variable.

@url{UNIFORM-RESOURCE-LOCATOR}
     Indicate a uniform resource locator for the World Wide Web.

@file{FILE-NAME}
     Indicate the name of a file.

@email{EMAIL-ADDRESS}
     Indicate an electronic mail address.

@dfn{TERM}
     Indicate the introductory or defining use of a term.

@cite{REFERENCE}
     Indicate the name of a book.

@code{SAMPLE-CODE}
------------------

Use the @code command to indicate text that is a piece of a program and which consists of entire syntactic tokens.  Enclose the text in braces.

Thus, you should use @code for an expression in a program, for the name of a variable or function used in a program, or for a keyword.  Also, you should use @code for the name of a program, such as diff, that is a name used in the machine. (You should write the name of a program in the ordinary text font if you regard it as a new English word, such as `Emacs' or `Bison'.)

Use @code for environment variables such as TEXINPUTS, and other variables.

Use @code for command names in command languages that resemble programming languages, such as Texinfo or the shell. For example, @code and @samp are produced by writing @code{@@code} and @code{@@samp} in the Texinfo source, respectively.

Note, however, that you should not use @code for shell options such as -c when such options stand alone. (Use @samp.) Also, an entire shell command often looks better if written using @samp rather than @code.  In this case, the rule is to choose the more pleasing format.

It is incorrect to alter the case of a word inside an @code command when it appears at the beginning of a sentence.  Most computer languages are case sensitive.  In C, for example, Printf is different from the identifier printf, and most likely is a misspelling of it.  Even in languages which are not case sensitive, it is confusing to a human reader to see identifiers spelled in different ways.  Pick one spelling and always use that.  If you do not want to start a sentence with a command written all in lower case, you should rearrange the sentence.

Do not use the @code command for a string of characters shorter than a syntactic token.  If you are writing about TEXINPU, which is just a part of the name for the TEXINPUTS environment variable, you should use @samp.

In particular, you should not use the @code command when writing about the characters used in a token; do not, for example, use @code when you are explaining what letters or printable symbols can be used in the names of functions.  (Use @samp.)  Also, you should not use @code to mark text that is considered input to programs unless the input is written in a language that is like a programming language.  For example, you should not use @code for the keystroke commands of GNU Emacs (use @kbd instead) although you may use @code for the names of the Emacs Lisp functions that the keystroke commands invoke.

In the printed manual, @code causes TeX to typeset the argument in a typewriter face.  In the Info file, it causes the Info formatting commands to use single quotation marks around the text.

For example,

     Use @code{diff} to compare two files.

produces this in the printed manual:

     Use diff to compare two files.

@kbd{KEYBOARD-CHARACTERS}
-------------------------

Use the @kbd command for characters of input to be typed by users.  For example, to refer to the characters M-a, write

     @kbd{M-a}

and to refer to the characters M-x shell, write

     @kbd{M-x shell}

The @kbd command has the same effect as @code in Info, but by default produces a different font (slanted typewriter instead of normal typewriter) in the printed manual, so users can distinguish the characters they are supposed to type from those the computer outputs.

Since the usage of @kbd varies from manual to manual, you can control the font switching with the @kbdinputstyle command. This command has no effect on Info output.  Write this command at the beginning of a line with a single word as an argument, one of the following:

code
     Always use the same font for @kbd as @code.

example
     Use the distinguishing font for @kbd only in @example and similar environments.

example
     (the default) Always use the distinguishing font for @kbd.

You can embed another @-command inside the braces of an @kbd command.  Here, for example, is the way to describe a command that would be described more verbosely as ``press an r and then press the RET key'':

     @kbd{r @key{RET}}

This produces: r RET

You also use the @kbd command if you are spelling out the letters you type; for example:

     To give the @code{logout} command,
     type the characters @kbd{l o g o u t @key{RET}}.

This produces:

     To give the logout command, type the characters l o g o u t RET.

(Also, this example shows that you can add spaces for clarity.  If you really want to mention a space character as one of the characters of input, write @key{SPC} for it.)

@key{KEY-NAME}
--------------

Use the @key command for the conventional name for a key on a keyboard, as in:

     @key{RET}

You can use the @key command within the argument of an @kbd command when the sequence of characters to be typed includes one or more keys that are described by name.

For example, to produce C-x ESC you would type:

     @kbd{C-x @key{ESC}}

Here is a list of the recommended names for keys:

     SPC
          Space

     RET
          Return

     LFD
          Linefeed (however, since most keyboards nowadays do not have a Linefeed key, it might be better to call this character C-j.

     TAB
          Tab

     BS
          Backspace

     ESC
          Escape

     DEL
          Delete

     SHIFT
          Shift

     CTRL
          Control

     META
          Meta

There are subtleties to handling words like `meta' or `ctrl' that are names of modifier keys.  When mentioning a character in which the modifier key is used, such as Meta-a, use the @kbd command alone; do not use the @key command; but when you are referring to the modifier key in isolation, use the @key command.  For example, write @kbd{Meta-a} to produce Meta-a and @key{META} to produce META.

@samp{TEXT}
-----------

Use the @samp command to indicate text that is a literal example or `sample' of a sequence of characters in a file, string, pattern, etc. Enclose the text in braces.  The argument appears within single quotation marks in both the Info file and the printed manual; in addition, it is printed in a fixed-width font.

     To match @samp{foo} at the end of the line,
     use the regexp @samp{foo$}.

produces

     To match foo at the end of the line, use the regexp foo$.

Any time you are referring to single characters, you should use @samp unless @kbd or @key is more appropriate. Use @samp for the names of command-line options (except in an @table, where @code seems to read more easily).  Also, you may use @samp for entire statements in C and for entire shell commands---in this case, @samp often looks better than @code.  Basically, @samp is a catchall for whatever is not covered by @code, @kbd, or @key.

Only include punctuation marks within braces if they are part of the string you are specifying.  Write punctuation marks outside the braces if those punctuation marks are part of the English text that surrounds the string.  In the following sentence, for example, the commas and period are outside of the braces:

     In English, the vowels are @samp{a}, @samp{e},
     @samp{i}, @samp{o}, @samp{u}, and sometimes
     @samp{y}.

This produces:

     In English, the vowels are a, e, i, o, u,  and sometimes y.

@var{METASYNTACTIC-VARIABLE}
----------------------------

Use the @var command to indicate metasyntactic variables.  A metasyntactic variable is something that stands for another piece of text.  For example, you should use a metasyntactic variable in the documentation of a function to describe the arguments that are passed to that function.

Do not use @var for the names of particular variables in programming languages.  These are specific names from a program, so @code is correct for them.  For example, the Emacs Lisp variable texinfo-tex-command is not a metasyntactic variable; it is properly formatted using @code.

The effect of @var in the Info file is to change the case of the argument to all upper case; in the printed manual, to italicize it.

For example,

     To delete file @var{filename},
     type @code{rm @var{filename}}.

produces

     To delete file FILENAME, type rm FILENAME.

(Note that @var may appear inside @code, @samp, @file, etc.)

Write a metasyntactic variable all in lower case without spaces, and use hyphens to make it more readable.  Thus, the Texinfo source for the illustration of how to begin a Texinfo manual looks like this:

     \input texinfo
     @@setfilename @var{info-file-name}
     @@settitle @var{name-of-manual}

This produces:

     \input texinfo
     @setfilename INFO-FILE-NAME
     @settitle NAME-OF-MANUAL

In some documentation styles, metasyntactic variables are shown with angle brackets, for example:

     ..., type rm <filename>

However, that is not the style that Texinfo uses.  (You can, of course, modify the sources to TeX and the Info formatting commands to output the <...> format if you wish.)

@file{FILE-NAME}
----------------

Use the @file command to indicate text that is the name of a file, buffer, or directory, or is the name of a node in Info.  You can also use the command for file name suffixes.  Do not use @file for symbols in a programming language; use @code.

Currently, @file is equivalent to @samp in its effects. For example,

     The @file{.el} files are in
     the @file{/usr/local/emacs/lisp} directory.

produces

     The .el files are in the /usr/local/emacs/lisp directory.

@dfn{TERM}
----------

Use the @dfn command to identify the introductory or defining use of a technical term.  Use the command only in passages whose purpose is to introduce a term which will be used again or which the reader ought to know.  Mere passing mention of a term for the first time does not deserve @dfn.  The command generates italics in the printed manual, and double quotation marks in the Info file.  For example:

     Getting rid of a file is called @dfn{deleting} it.

produces

     Getting rid of a file is called deleting it.

As a general rule, a sentence containing the defining occurrence of a term should be a definition of the term.  The sentence does not need to say explicitly that it is a definition, but it should contain the information of a definition---it should make the meaning clear.

@cite{REFERENCE}
----------------

Use the @cite command for the name of a book that lacks a companion Info file. The command produces italics in the printed manual, and quotation marks in the Info file.

(If a book is written in Texinfo, it is better to use a cross reference command since a reader can easily follow such a reference in Info. See @xref.)

@url{UNIFORM-RESOURCE-LOCATOR}
------------------------------

Use the @url to indicate a uniform resource locator on the World Wide Web.  This is analogous to @file, @var, etc., and is purely for markup purposes.  It does not produce a link you can follow in HTML output (the @uref command does, see @uref).  It is useful for example URL's which do not actually exist.  For example:

     For example, the url might be
     @url{http://host.domain.org/path}.

@email{EMAIL-ADDRESS}
---------------------

Use the @email command to indicate an electronic mail address. For example:

     Send bug reports to @email{bug-texinfo@prep.ai.mit.edu}.

In Info and TeX, this acts like @key (it puts the argument in angle brackets).  When we have support for converting Texinfo to HTML, this will produce a link you can follow to bring up a mail composition window initialized with EMAIL-ADDRESS.

Emphasizing Text
================

Usually, Texinfo changes the font to mark words in the text according to what category the words belong to; an example is the @code command. Most often, this is the best way to mark words. However, sometimes you will want to emphasize text without indicating a category.  Texinfo has two commands to do this.  Also, Texinfo has several commands that specify the font in which TeX will typeset text.  These commands have no affect on Info and only one of them, the @r command, has any regular use.

@emph{TEXT} and @strong{TEXT}
-----------------------------

The @emph and @strong commands are for emphasis; @strong is stronger.  In printed output, @emph produces italics and @strong produces bold.

For example,

     @quotation
     @strong{Caution:} @samp{rm * .[^.]*} removes @emph{all}
     files in the directory.
     @end quotation

produces:

          *Caution*: `rm * .[^.]*' removes *all*
          files in the directory.

The @strong command is seldom used except to mark what is, in effect, a typographical element, such as the word `Caution' in the preceding example.

In the Info file, both @emph and @strong put asterisks around the text.

     Caution: Do not use @emph or @strong with the word Note; Info will mistake the combination for a cross reference.  Use a phrase such as Please note or Caution instead.

@sc{TEXT}: The Small Caps Font
------------------------------

Use the @sc command to set text in the printed output in a small caps font and set text in the Info file in upper case letters.

Write the text between braces in lower case, like this:

     The @sc{acm} and @sc{ieee} are technical societies.

This produces:

     The ACM and IEEE are technical societies.

TeX typesets the small caps font in a manner that prevents the letters from `jumping out at you on the page'.  This makes small caps text easier to read than text in all upper case.  The Info formatting commands set all small caps text in upper case.

If the text between the braces of an @sc command is upper case, TeX typesets in full-size capitals.  Use full-size capitals sparingly.

You may also use the small caps font for a jargon word such as ATO (a NASA word meaning `abort to orbit').

There are subtleties to using the small caps font with a jargon word such as CDR, a word used in Lisp programming.  In this case, you should use the small caps font when the word refers to the second and subsequent elements of a list (the CDR of the list), but you should use @code when the word refers to the Lisp function of the same spelling.

Fonts for Printing, Not Info
----------------------------

Texinfo provides four font commands that specify font changes in the printed manual but have no effect in the Info file.  @i requests italic font (in some versions of TeX, a slanted font is used), @b requests bold face, @t requests the fixed-width, typewriter-style font used by @code, and @r requests a roman font, which is the usual font in which text is printed.  All four commands apply to an argument that follows, surrounded by braces.

Only the @r command has much use: in example programs, you can use the @r command to convert code comments from the fixed-width font to a roman font.  This looks better in printed output.

For example,

     @lisp
     (+ 2 2)    ; @r{Add two plus two.}
     @end lisp

produces

     (+ 2 2)    ; Add two plus two.

If possible, you should avoid using the other three font commands.  If you need to use one, it probably indicates a gap in the Texinfo language.

Customized Highlighting
-----------------------

You can use regular TeX commands inside of @iftex ... @end iftex to create your own customized highlighting commands for Texinfo.  The easiest way to do this is to equate your customized commands with pre-existing commands, such as those for italics.  Such new commands work only with TeX.

You can use the @definfoenclose command inside of @ifinfo ... @end ifinfo to define commands for Info with the same names as new commands for TeX. @definfoenclose creates new commands for Info that mark text by enclosing it in strings that precede and follow the text. (Currently, @definfoenclose works only with texinfo-format-buffer and texinfo-format-region, not with makeinfo.)

Here is how to create a new @-command called @phoo that causes TeX to typeset its argument in italics and causes Info to display the argument between // and \\.

For TeX, write the following to equate the @phoo command with the existing @i italics command:

     @iftex
     @global@let@phoo=@i
     @end iftex

This defines @phoo as a command that causes TeX to typeset the argument to @phoo in italics.  @global@let tells TeX to equate the next argument with the argument that follows the equals sign.

For Info, write the following to tell the Info formatters to enclose the argument between // and \\:

     @ifinfo
     @definfoenclose phoo, //, \\
     @end ifinfo

Write the @definfoenclose command on a line and follow it with three arguments separated by commas (commas are used as separators in an @node line in the same way).

  * The first argument to @definfoenclose is the @-command name without the @;

  * the second argument is the Info start delimiter string; and,

  * the third argument is the Info end delimiter string.

The latter two arguments enclose the highlighted text in the Info file. A delimiter string may contain spaces.  Neither the start nor end delimiter is required.  However, if you do not provide a start delimiter, you must follow the command name with two commas in a row; otherwise, the Info formatting commands will misinterpret the end delimiter string as a start delimiter string.

After you have defined @phoo both for TeX and for Info, you can then write @phoo{bar} to see //bar\\ in Info and see bar in italics in printed output.

Note that each definition applies to its own formatter: one for TeX, the other for Info.

Here is another example:

     @ifinfo
     @definfoenclose headword, , :
     @end ifinfo
     @iftex
     @global@let@headword=@b
     @end iftex

This defines @headword as an Info formatting command that inserts nothing before and a colon after the argument and as a TeX formatting command to typeset its argument in bold.

Quotations and Examples
***********************

Quotations and examples are blocks of text consisting of one or more whole paragraphs that are set off from the bulk of the text and treated differently.  They are usually indented.

In Texinfo, you always begin a quotation or example by writing an @-command at the beginning of a line by itself, and end it by writing an @end command that is also at the beginning of a line by itself.  For instance, you begin an example by writing @example by itself at the beginning of a line and end the example by writing @end example on a line by itself, at the beginning of that line.

The Block Enclosing Commands
============================

Here are commands for quotations and examples:

@quotation
     Indicate text that is quoted. The text is filled, indented, and printed in a roman font by default.

@example
     Illustrate code, commands, and the like. The text is printed in a fixed-width font, and indented but not filled.

@lisp
     Illustrate Lisp code. The text is printed in a fixed-width font, and indented but not filled.

@smallexample
     Illustrate code, commands, and the like.  Similar to @example, except that in TeX this command typesets text in a smaller font for the smaller @smallbook format than for the 8.5 by 11 inch format.

@smalllisp
     Illustrate Lisp code.  Similar to @lisp, except that in TeX this command typesets text in a smaller font for the smaller @smallbook format than for the 8.5 by 11 inch format.

@display
     Display illustrative text.  The text is indented but not filled, and no font is specified (so, by default, the font is roman).

@format
     Print illustrative text.  The text is not indented and not filled and no font is specified (so, by default, the font is roman).

The @exdent command is used within the above constructs to undo the indentation of a line.

The @flushleft and @flushright commands are used to line up the left or right margins of unfilled text.

The @noindent command may be used after one of the above constructs to prevent the following text from being indented as a new paragraph.

You can use the @cartouche command within one of the above constructs to highlight the example or quotation by drawing a box with rounded corners around it.  (The @cartouche command affects only the printed manual; it has no effect in the Info file; see Drawing Cartouches Around Examples.)

@quotation
==========

The text of a quotation is processed normally except that:

  * the margins are closer to the center of the page, so the whole of the quotation is indented;

  * the first lines of paragraphs are indented no more than other lines;

  * in the printed output, interparagraph spacing is reduced.

     This is an example of text written between an @quotation command and an @end quotation command.  An @quotation command is most often used to indicate text that is excerpted from another (real or hypothetical) printed work.

Write an @quotation command as text on a line by itself.  This line will disappear from the output.  Mark the end of the quotation with a line beginning with and containing only @end quotation. The @end quotation line will likewise disappear from the output.  Thus, the following,

     @quotation
     This is
     a foo.
     @end quotation

produces

     This is a foo.

@example
========

The @example command is used to indicate an example that is not part of the running text, such as computer input or output.

     This is an example of text written between an
     @example command
     and an @end example command.
     The text is indented but not filled.

     In the printed manual, the text is typeset in a
     fixed-width font, and extra spaces and blank lines are
     significant.  In the Info file, an analogous result is
     obtained by indenting each line with five spaces.

Write an @example command at the beginning of a line by itself. This line will disappear from the output.  Mark the end of the example with an @end example command, also written at the beginning of a line by itself.  The @end example will disappear from the output.

For example,

     @example
     mv foo bar
     @end example

produces

     mv foo bar

Since the lines containing @example and @end example will disappear, you should put a blank line before the @example and another blank line after the @end example.  (Remember that blank lines between the beginning @example and the ending @end example will appear in the output.)

     Caution: Do not use tabs in the lines of an example (or anywhere else in Texinfo, for that matter)!  TeX treats tabs as single spaces, and that is not what they look like.  This is a problem with TeX.  (If necessary, in Emacs, you can use M-x untabify to convert tabs in a region to multiple spaces.)

Examples are often, logically speaking, ``in the middle'' of a paragraph, and the text continues after an example should not be indented.  The @noindent command prevents a piece of text from being indented as if it were a new paragraph. (see noindent.)

(The @code command is used for examples of code that are embedded within sentences, not set off from preceding and following text.  See @code.)

@noindent
=========

An example or other inclusion can break a paragraph into segments. Ordinarily, the formatters indent text that follows an example as a new paragraph.  However, you can prevent this by writing @noindent at the beginning of a line by itself preceding the continuation text.

For example:

     @example
     This is an example
     @end example

     @noindent
     This line is not indented.  As you can see, the
     beginning of the line is fully flush left with the line
     that follows after it.  (This whole example is between
     @code{@@display} and @code{@@end display}.)

produces

          This is an example

     This line is not indented.  As you can see, the
     beginning of the line is fully flush left with the line
     that follows after it.  (This whole example is between
     @display and @end display.)

To adjust the number of blank lines properly in the Info file output, remember that the line containing @noindent does not generate a blank line, and neither does the @end example line.

In the Texinfo source file for this manual, each line that says `produces' is preceded by a line containing @noindent.

Do not put braces after an @noindent command; they are not necessary, since @noindent is a command used outside of paragraphs (see Command Syntax).

@lisp
=====

The @lisp command is used for Lisp code.  It is synonymous with the @example command.

     This is an example of text written between an
     @lisp command and an @end lisp command.

Use @lisp instead of @example to preserve information regarding the nature of the example.  This is useful, for example, if you write a function that evaluates only and all the Lisp code in a Texinfo file.  Then you can use the Texinfo file as a Lisp library. (It would be straightforward to extend Texinfo to work in a similar fashion for C, Fortran, or other languages.)

Mark the end of @lisp with @end lisp on a line by itself.

@smallexample and @smalllisp
============================

In addition to the regular @example and @lisp commands, Texinfo has two other ``example-style'' commands.  These are the @smallexample and @smalllisp commands.  Both these commands are designed for use with the @smallbook command that causes TeX to produce a printed manual in a 7 by 9.25 inch format rather than the regular 8.5 by 11 inch format.

In TeX, the @smallexample and @smalllisp commands typeset text in a smaller font for the smaller @smallbook format than for the 8.5 by 11 inch format.  Consequently, many examples containing long lines fit in a narrower, @smallbook page without needing to be shortened.  Both commands typeset in the normal font size when you format for the 8.5 by 11 inch size; indeed, in this situation, the @smallexample and @smalllisp commands are defined to be the @example and @lisp commands.

In Info, the @smallexample and @smalllisp commands are equivalent to the @example and @lisp commands, and work exactly the same.

Mark the end of @smallexample or @smalllisp with @end smallexample or @end smalllisp, respectively.

     This is an example of text written between @smallexample and
     @end smallexample.  In Info and in an 8.5 by 11 inch manual,
     this text appears in its normal size; but in a 7 by 9.25 inch manual,
     this text appears in a smaller font.

The @smallexample and @smalllisp commands make it easier to prepare smaller format manuals without forcing you to edit examples by hand to fit them onto narrower pages.

As a general rule, a printed document looks better if you write all the examples in a chapter consistently in @example or in @smallexample.  Only occasionally should you mix the two formats.

See Printing ``Small'' Books, for more information about the @smallbook command.

@display
========

The @display command begins a kind of example.  It is like the @example command except that, in a printed manual, @display does not select the fixed-width font.  In fact, it does not specify the font at all, so that the text appears in the same font it would have appeared in without the @display command.

     This is an example of text written between an @display command
     and an @end display command.  The @display command
     indents the text, but does not fill it.

@format
=======

The @format command is similar to @example except that, in the printed manual, @format does not select the fixed-width font and does not narrow the margins.

     This is an example of text written between an @format command
     and an @end format command.  As you can see
     from this example,
     the @format command does not fill the text.

@exdent: Undoing a Line's Indentation
=====================================

The @exdent command removes any indentation a line might have. The command is written at the beginning of a line and applies only to the text that follows the command that is on the same line.  Do not use braces around the text.  In a printed manual, the text on an @exdent line is printed in the roman font.

@exdent is usually used within examples.  Thus,

     @example
     This line follows an @@example command.
     @exdent This line is exdented.
     This line follows the exdented line.
     The @@end example comes on the next line.
     @end group

produces

     This line follows an @example command.
     This line is exdented.
     This line follows the exdented line.
     The @end example comes on the next line.

In practice, the @exdent command is rarely used. Usually, you un-indent text by ending the example and returning the page to its normal width.

@flushleft and @flushright
==========================

The @flushleft and @flushright commands line up the ends of lines on the left and right margins of a page, but do not fill the text.  The commands are written on lines of their own, without braces.  The @flushleft and @flushright commands are ended by @end flushleft and @end flushright commands on lines of their own.

For example,

     @flushleft
     This text is
     written flushleft.
     @end flushleft

produces

     This text is
     written flushleft.

@flushright produces the type of indentation often used in the return address of letters.  For example,

     @flushright
     Here is an example of text written
     flushright.  The @code{@flushright} command
     right justifies every line but leaves the
     left end ragged.
     @end flushright

produces

Here is an example of text written
flushright.  The @flushright command
right justifies every line but leaves the
left end ragged.

Drawing Cartouches Around Examples
==================================

In a printed manual, the @cartouche command draws a box with rounded corners around its contents.  You can use this command to further highlight an example or quotation.  For instance, you could write a manual in which one type of example is surrounded by a cartouche for emphasis.

The @cartouche command affects only the printed manual; it has no effect in the Info file.

For example,

     @example
     @cartouche
     % pwd
     /usr/local/share/emacs
     @end cartouche
     @end example

surrounds the two-line example with a box with rounded corners, in the printed manual.

Lists and Tables
****************

Texinfo has several ways of making lists and tables.  Lists can be bulleted or numbered; two-column tables can highlight the items in the first column; multi-column tables are also supported.

Introducing Lists
=================

Texinfo automatically indents the text in lists or tables, and numbers an enumerated list.  This last feature is useful if you modify the list, since you do not need to renumber it yourself.

Numbered lists and tables begin with the appropriate @-command at the beginning of a line, and end with the corresponding @end command on a line by itself.  The table and itemized-list commands also require that you write formatting information on the same line as the beginning @-command.

Begin an enumerated list, for example, with an @enumerate command and end the list with an @end enumerate command. Begin an itemized list with an @itemize command, followed on the same line by a formatting command such as @bullet, and end the list with an @end itemize command.

Precede each element of a list with an @item or @itemx command.

Here is an itemized list of the different kinds of table and lists:

  * Itemized lists with and without bullets.

  * Enumerated lists, using numbers or letters.

  * Two-column tables with highlighting.

Here is an enumerated list with the same items:

 1. Itemized lists with and without bullets.

 2. Enumerated lists, using numbers or letters.

 3. Two-column tables with highlighting.

And here is a two-column table with the same items and their @-commands:

@itemize
     Itemized lists with and without bullets.

@enumerate
     Enumerated lists, using numbers or letters.

@table
@ftable
@vtable
     Two-column tables with indexing.

Making an Itemized List
=======================

The @itemize command produces sequences of indented paragraphs, with a bullet or other mark inside the left margin at the beginning of each paragraph for which such a mark is desired.

Begin an itemized list by writing @itemize at the beginning of a line.  Follow the command, on the same line, with a character or a Texinfo command that generates a mark.  Usually, you will write @bullet after @itemize, but you can use @minus, or any character or any special symbol that results in a single character in the Info file.  (When you write @bullet or @minus after an @itemize command, you may omit the {}.)

Write the text of the indented paragraphs themselves after the @itemize, up to another line that says @end itemize.

Before each paragraph for which a mark in the margin is desired, write a line that says just @item.  Do not write any other text on this line.

Usually, you should put a blank line before an @item.  This puts a blank line in the Info file. (TeX inserts the proper interline whitespace in either case.)  Except when the entries are very brief, these blank lines make the list look better.

Here is an example of the use of @itemize, followed by the output it produces.  Note that @bullet produces an * in Info and a round dot in TeX.

     @itemize @bullet
     @item
     Some text for foo.

     @item
     Some text
     for bar.
     @end itemize

This produces:

       * Some text for foo.

       * Some text for bar.

Itemized lists may be embedded within other itemized lists.  Here is a list marked with dashes embedded in a list marked with bullets:

     @itemize @bullet
     @item
     First item.

     @itemize @minus
     @item
     Inner item.

     @item
     Second inner item.
     @end itemize

     @item
     Second outer item.
     @end itemize

This produces:

       * First item.

            - Inner item.

            - Second inner item.

       * Second outer item.

Making a Numbered or Lettered List
==================================

@enumerate is like @itemize (see @itemize), except that the labels on the items are successive integers or letters instead of bullets.

Write the @enumerate command at the beginning of a line.  The command does not require an argument, but accepts either a number or a letter as an option.  Without an argument, @enumerate starts the list with the number 1.  With a numeric argument, such as 3, the command starts the list with that number.  With an upper or lower case letter, such as a or A, the command starts the list with that letter.

Write the text of the enumerated list in the same way you write an itemized list: put @item on a line of its own before the start of each paragraph that you want enumerated.  Do not write any other text on the line beginning with @item.

You should put a blank line between entries in the list. This generally makes it easier to read the Info file.

Here is an example of @enumerate without an argument:

     @enumerate
     @item
     Underlying causes.

     @item
     Proximate causes.
     @end enumerate

This produces:

 1. Underlying causes.

 2. Proximate causes.

Here is an example with an argument of 3:

     @enumerate 3
     @item
     Predisposing causes.

     @item
     Precipitating causes.

     @item
     Perpetuating causes.
     @end enumerate

This produces:

 3. Predisposing causes.

 4. Precipitating causes.

 5. Perpetuating causes.

Here is a brief summary of the alternatives.  The summary is constructed using @enumerate with an argument of a.

 a. @enumerate

     Without an argument, produce a numbered list, starting with the number 1.

 b. @enumerate POSITIVE-INTEGER

     With a (positive) numeric argument, start a numbered list with that number.  You can use this to continue a list that you interrupted with other text.

 c. @enumerate UPPER-CASE-LETTER

     With an upper case letter as argument, start a list in which each item is marked by a letter, beginning with that upper case letter.

 d. @enumerate LOWER-CASE-LETTER

     With a lower case letter as argument, start a list in which each item is marked by a letter, beginning with that lower case letter.

You can also nest enumerated lists, as in an outline.

Making a Two-column Table
=========================

@table is similar to @itemize (see @itemize), but allows you to specify a name or heading line for each item.  The @table command is used to produce two-column tables, and is especially useful for glossaries, explanatory exhibits, and command-line option summaries.

Using the @table Command
------------------------

Use the @table command to produce two-column tables.

Write the @table command at the beginning of a line and follow it on the same line with an argument that is a Texinfo ``indicating'' command such as @code, @samp, @var, or @kbd (see Indicating).  Although these commands are usually followed by arguments in braces, in this case you use the command name without an argument because @item will supply the argument. This command will be applied to the text that goes into the first column of each item and determines how it will be highlighted.  For example, @code will cause the text in the first column to be highlighted with an @code command.  (We recommend @code for @table's of command-line options.)

You may also choose to use the @asis command as an argument to @table.  @asis is a command that does nothing; if you use this command after @table, TeX and the Info formatting commands output the first column entries without added highlighting (``as is'').

(The @table command may work with other commands besides those listed here.  However, you can only use commands that normally take arguments in braces.)

Begin each table entry with an @item command at the beginning of a line.  Write the first column text on the same line as the @item command.  Write the second column text on the line following the @item line and on subsequent lines.  (You do not need to type anything for an empty second column entry.)  You may write as many lines of supporting text as you wish, even several paragraphs.  But only text on the same line as the @item will be placed in the first column.

Normally, you should put a blank line before an @item line. This puts a blank like in the Info file.  Except when the entries are very brief, a blank line looks better.

The following table, for example, highlights the text in the first column with an @samp command:

     @table @samp
     @item foo
     This is the text for
     @samp{foo}.

     @item bar
     Text for @samp{bar}.
     @end table

This produces:

foo
     This is the text for foo.

bar
     Text for bar.

If you want to list two or more named items with a single block of text, use the @itemx command.  (see @itemx.)

@ftable and @vtable
-------------------

The @ftable and @vtable commands are the same as the @table command except that @ftable automatically enters each of the items in the first column of the table into the index of functions and @vtable automatically enters each of the items in the first column of the table into the index of variables.  This simplifies the task of creating indices.  Only the items on the same line as the @item commands are indexed, and they are indexed in exactly the form that they appear on that line.  See Creating Indices, for more information about indices.

Begin a two-column table using @ftable or @vtable by writing the @-command at the beginning of a line, followed on the same line by an argument that is a Texinfo command such as @code, exactly as you would for an @table command; and end the table with an @end ftable or @end vtable command on a line by itself.

See the example for @table in the previous section.

@itemx
------

Use the @itemx command inside a table when you have two or more first column entries for the same item, each of which should appear on a line of its own.  Use @itemx for all but the first entry; @itemx should always follow an @item command.  The @itemx command works exactly like @item except that it does not generate extra vertical space above the first column text.

For example,

     @table @code
     @item upcase
     @itemx downcase
     These two functions accept a character or a string as
     argument, and return the corresponding upper case (lower
     case) character or string.
     @end table

This produces:

upcase
downcase
     These two functions accept a character or a string as argument, and return the corresponding upper case (lower case) character or string.

(Note also that this example illustrates multi-line supporting text in a two-column table.)

Multi-column Tables
===================

@multitable allows you to construct tables with any number of columns, with each column having any width you like.

You define the column widths on the @multitable line itself, and write each row of the actual table following an @item command, with columns separated by an @tab command.  Finally, @end multitable completes the table.  Details in the sections below.

Multitable Column Widths
------------------------

You can define the column widths for a multitable in two ways: as fractions of the line length; or with a prototype row.  Mixing the two methods is not supported.  In either case, the widths are defined entirely on the same line as the @multitable command.

 1. To specify column widths as fractions of the line length, write @columnfractions and the decimal numbers (presumably less than 1) after the @multitable command, as in:

          @multitable @columnfractions .33 .33 .33

     The fractions need not add up exactly to 1.0, as these do not.  This allows you to produce tables that do not need the full line length.

 2. To specify a prototype row, write the longest entry for each column enclosed in braces after the @multitable command.  For example:

          @multitable {some text for column one} {for column two}

     The first column will then have the width of the typeset `some text for column one', and the second column the width of `for column two'.

     The prototype entries need not appear in the table itself.

     Although we used simple text in this example, the prototype entries can contain Texinfo commands; markup commands such as @code are particularly likely to be useful.

Multitable Rows
---------------

After the @multitable command defining the column widths (see the previous section), you begin each row in the body of a multitable with @item, and separate the column entries with @tab. Line breaks are not special within the table body, and you may break input lines in your source file as necessary.

Here is a complete example of a multi-column table (the text is from The GNU Emacs Manual, see Splitting Windows (The GNU Emacs Manual)):

     @multitable @columnfractions .15 .45 .4
     @item Key @tab Command @tab Description
     @item C-x 2
     @tab @code{split-window-vertically}
     @tab Split the selected window into two windows,
     with one above the other.
     @item C-x 3
     @tab @code{split-window-horizontally}
     @tab Split the selected window into two windows
     positioned side by side.
     @item C-Mouse-2
     @tab
     @tab In the mode line or scroll bar of a window,
     split that window.
     @end multitable

produces:

Key   Command   Description
C-x 2
split-window-vertically
Split the selected window into two windows,
with one above the other.
C-x 3
split-window-horizontally
Split the selected window into two windows
positioned side by side.
C-Mouse-2

In the mode line or scroll bar of a window,
split that window.

Creating Indices
****************

Using Texinfo, you can generate indices without having to sort and collate entries manually.  In an index, the entries are listed in alphabetical order, together with information on how to find the discussion of each entry.  In a printed manual, this information consists of page numbers.  In an Info file, this information is a menu entry leading to the first node referenced.

Texinfo provides several predefined kinds of index: an index for functions, an index for variables, an index for concepts, and so on.  You can combine indices or use them for other than their canonical purpose.  If you wish, you can define your own indices.

Making Index Entries
====================

When you are making index entries, it is good practice to think of the different ways people may look for something.  Different people do not think of the same words when they look something up.  A helpful index will have items indexed under all the different words that people may use.  For example, one reader may think it obvious that the two-letter names for indices should be listed under ``Indices, two-letter names'', since the word ``Index'' is the general concept. But another reader may remember the specific concept of two-letter names and search for the entry listed as ``Two letter names for indices''.  A good index will have both entries and will help both readers.

Like typesetting, the construction of an index is a highly skilled, professional art, the subtleties of which are not appreciated until you need to do it yourself.

See Printing Indices & Menus, for information about printing an index at the end of a book or creating an index menu in an Info file.

Predefined Indices
==================

Texinfo provides six predefined indices:

  * A concept index listing concepts that are discussed.

  * A function index listing functions (such as entry points of libraries).

  * A variables index listing variables (such as global variables of libraries).

  * A keystroke index listing keyboard commands.

  * A program index listing names of programs.

  * A data type index listing data types (such as structures defined in header files).

Not every manual needs all of these, and most manuals use two or three of them.  This manual has two indices: a concept index and an @-command index (that is actually the function index but is called a command index in the chapter heading).  Two or more indices can be combined into one using the @synindex or @syncodeindex commands.  See Combining Indices.

Defining the Entries of an Index
================================

The data to make an index come from many individual indexing commands scattered throughout the Texinfo source file.  Each command says to add one entry to a particular index; after formatting, the index will give the current page number or node name as the reference.

An index entry consists of an indexing command at the beginning of a line followed, on the rest of the line, by the entry.

For example, this section begins with the following five entries for the concept index:

     @cindex Defining indexing entries
     @cindex Index entries
     @cindex Entries for an index
     @cindex Specifying index entries
     @cindex Creating index entries

Each predefined index has its own indexing command---@cindex for the concept index, @findex for the function index, and so on.

Concept index entries consist of text.  The best way to write an index is to choose entries that are terse yet clear.  If you can do this, the index often looks better if the entries are not capitalized, but written just as they would appear in the middle of a sentence. (Capitalize proper names and acronyms that always call for upper case letters.)  This is the case convention we use in most GNU manuals' indices.

If you don't see how to make an entry terse yet clear, make it longer and clear---not terse and confusing.  If many of the entries are several words long, the index may look better if you use a different convention: to capitalize the first word of each entry.  But do not capitalize a case-sensitive name such as a C or Lisp function name or a shell command; that would be a spelling error.

Whichever case convention you use, please use it consistently!

Entries in indices other than the concept index are symbol names in programming languages, or program names; these names are usually case-sensitive, so use upper and lower case as required for them.

By default, entries for a concept index are printed in a small roman font and entries for the other indices are printed in a small @code font.  You may change the way part of an entry is printed with the usual Texinfo commands, such as @file for file names and @emph for emphasis (see Marking Text).

The six indexing commands for predefined indices are:

@cindex CONCEPT
     Make an entry in the concept index for CONCEPT.

@findex FUNCTION
     Make an entry in the function index for FUNCTION.

@vindex VARIABLE
     Make an entry in the variable index for VARIABLE.

@kindex KEYSTROKE
     Make an entry in the key index for KEYSTROKE.

@pindex PROGRAM
     Make an entry in the program index for PROGRAM.

@tindex DATA TYPE
     Make an entry in the data type index for DATA TYPE.

     Caution: Do not use a colon in an index entry.  In Info, a colon separates the menu entry name from the node name.  An extra colon confuses Info. See The Parts of a Menu, for more information about the structure of a menu entry.

If you write several identical index entries in different places in a Texinfo file, the index in the printed manual will list all the pages to which those entries refer.  However, the index in the Info file will list only the node that references the first of those index entries.  Therefore, it is best to write indices in which each entry refers to only one place in the Texinfo file.  Fortunately, this constraint is a feature rather than a loss since it means that the index will be easy to use.  Otherwise, you could create an index that lists several pages for one entry and your reader would not know to which page to turn.  If you have two identical entries for one topic, change the topics slightly, or qualify them to indicate the difference.

You are not actually required to use the predefined indices for their canonical purposes.  For example, suppose you wish to index some C preprocessor macros.  You could put them in the function index along with actual functions, just by writing @findex commands for them; then, when you print the ``Function Index'' as an unnumbered chapter, you could give it the title `Function and Macro Index' and all will be consistent for the reader.  Or you could put the macros in with the data types by writing @tindex commands for them, and give that index a suitable title so the reader will understand. (see Printing Indices & Menus.)

Combining Indices
=================

Sometimes you will want to combine two disparate indices such as functions and concepts, perhaps because you have few enough of one of them that a separate index for them would look silly.

You could put functions into the concept index by writing @cindex commands for them instead of @findex commands, and produce a consistent manual by printing the concept index with the title `Function and Concept Index' and not printing the `Function Index' at all; but this is not a robust procedure.  It works only if your document is never included as part of another document that is designed to have a separate function index; if your document were to be included with such a document, the functions from your document and those from the other would not end up together. Also, to make your function names appear in the right font in the concept index, you would need to enclose every one of them between the braces of @code.

@syncodeindex
-------------

When you want to combine functions and concepts into one index, you should index the functions with @findex and index the concepts with @cindex, and use the @syncodeindex command to redirect the function index entries into the concept index.

The @syncodeindex command takes two arguments; they are the name of the index to redirect, and the name of the index to redirect it to. The template looks like this:

     @syncodeindex FROM TO

For this purpose, the indices are given two-letter names:

cp
     concept index

fn
     function index

vr
     variable index

ky
     key index

pg
     program index

tp
     data type index

Write an @syncodeindex command before or shortly after the end-of-header line at the beginning of a Texinfo file.  For example, to merge a function index with a concept index, write the following:

     @syncodeindex fn cp

This will cause all entries designated for the function index to merge in with the concept index instead.

To merge both a variables index and a function index into a concept index, write the following:

     @syncodeindex vr cp
     @syncodeindex fn cp

The @syncodeindex command puts all the entries from the `from' index (the redirected index) into the @code font, overriding whatever default font is used by the index to which the entries are now directed.  This way, if you direct function names from a function index into a concept index, all the function names are printed in the @code font as you would expect.

@synindex
---------

The @synindex command is nearly the same as the @syncodeindex command, except that it does not put the `from' index  entries into the @code font; rather it puts them in the roman font.  Thus, you use @synindex when you merge a concept index into a function index.

See Printing Indices & Menus, for information about printing an index at the end of a book or creating an index menu in an Info file.

Defining New Indices
====================

In addition to the predefined indices, you may use the @defindex and @defcodeindex commands to define new indices.  These commands create new indexing @-commands with which you mark index entries.  The @defindex command is used like this:

     @defindex NAME

The name of an index should be a two letter word, such as au. For example:

     @defindex au

This defines a new index, called the au index.  At the same time, it creates a new indexing command, @auindex, that you can use to make index entries.  Use the new indexing command just as you would use a predefined indexing command.

For example, here is a section heading followed by a concept index entry and two au index entries.

     @section Cognitive Semantics
     @cindex kinesthetic image schemas
     @auindex Johnson, Mark
     @auindex Lakoff, George

(Evidently, au serves here as an abbreviation for ``author''.) Texinfo constructs the new indexing command by concatenating the name of the index with index; thus, defining an au index leads to the automatic creation of an @auindex command.

Use the @printindex command to print the index, as you do with the predefined indices.  For example:

     @node Author Index, Subject Index, , Top
     @unnumbered Author Index

     @printindex au

The @defcodeindex is like the @defindex command, except that, in the printed output, it prints entries in an @code font instead of a roman font.  Thus, it parallels the @findex command rather than the @cindex command.

You should define new indices within or right after the end-of-header line of a Texinfo file, before any @synindex or @syncodeindex commands (see Header).

Special Insertions
******************

Texinfo provides several commands for inserting characters that have special meaning in Texinfo, such as braces, and for other graphic elements that do not correspond to simple characters you can type.

Inserting @ and Braces
======================

@ and curly braces are special characters in Texinfo.  To insert these characters so they appear in text, you must put an @ in front of these characters to prevent Texinfo from misinterpreting them.

Do not put braces after any of these commands; they are not necessary.

Inserting @ with @@
-------------------

@@ stands for a single @ in either printed or Info output.

Do not put braces after an @@ command.

Inserting { and }with @{ and @}
-------------------------------

@{ stands for a single { in either printed or Info output.

@} stands for a single } in either printed or Info output.

Do not put braces after either an @{ or an @} command.

Inserting Space
===============

The following sections describe commands that control spacing of various kinds within and after sentences.

Not Ending a Sentence
---------------------

Depending on whether a period or exclamation point or question mark is inside or at the end of a sentence, less or more space is inserted after a period in a typeset manual.  Since it is not always possible for Texinfo to determine when a period ends a sentence and when it is used in an abbreviation, special commands are needed in some circumstances. (Usually, Texinfo can guess how to handle periods, so you do not need to use the special commands; you just enter a period as you would if you were using a typewriter, which means you put two spaces after the period, question mark, or exclamation mark that ends a sentence.)

Use the @: command after a period, question mark, exclamation mark, or colon that should not be followed by extra space. For example, use @: after periods that end abbreviations which are not at the ends of sentences.

For example,

     The s.o.p.@: has three parts ...
     The s.o.p. has three parts ...

produces

     The s.o.p. has three parts ...

     The s.o.p. has three parts ...

(Incidentally, s.o.p. is an abbreviation for ``Standard Operating Procedure''.)

@: has no effect on the Info output.  Do not put braces after @:.

Ending a Sentence
-----------------

Use @. instead of a period, @! instead of an exclamation point, and @? instead of a question mark at the end of a sentence that ends with a single capital letter.  Otherwise, TeX will think the letter is an abbreviation and will not insert the correct end-of-sentence spacing.  Here is an example:

     Give it to M.I.B. and to M.E.W@.  Also, give it to R.J.C@.
     Give it to M.I.B. and to M.E.W.  Also, give it to R.J.C.

produces

     Give it to M.I.B. and to M.E.W.  Also, give it to R.J.C.

     Give it to M.I.B. and to M.E.W.  Also, give it to R.J.C.

In the Info file output, @. is equivalent to a simple .; likewise for @! and @?.

The meanings of @: and @. in Texinfo are designed to work well with the Emacs sentence motion commands (see Sentences (The GNU Emacs Manual)).  This made it necessary for them to be incompatible with some other formatting systems that use @-commands.

Do not put braces after any of these commands.

Multiple Spaces
---------------

Ordinarily, TeX collapses multiple whitespace characters (space, tab, and newline) into a single space.  Info output, on the other hand, preserves whitespace as you type it, except for changing a newline into a space; this is why it is important to put two spaces at the end of sentences in Texinfo documents.

Occasionally, you may want to actually insert several consecutive spaces, either for purposes of example (what your program does with multiple spaces as input), or merely for purposes of appearance in headings or lists.  Texinfo supports three commands: @SPACE, @TAB, and @NL, all of which insert a single space into the output.  (Here, @SPACE represents an @ character followed by a space, i.e., @ , and TAB and NL represent the tab character and end-of-line, i.e., when @ is the last character on a line.)

For example,

     Spacey@ @ @ @
     example.

produces

     Spacey
     example.

Other possible uses of @SPACE have been subsumed by @multitable (see Multi-column Tables).

Do not follow any of these commands with braces.

@dmn{DIMENSION}: Format a Dimension
-----------------------------------

At times, you may want to write 12pt or 8.5in with little or no space between the number and the abbreviation for the dimension.  You can use the @dmn command to do this.  On seeing the command, TeX inserts just enough space for proper typesetting; the Info formatting commands insert no space at all, since the Info file does not require it.

To use the @dmn command, write the number and then follow it immediately, with no intervening space, by @dmn, and then by the dimension within braces.  For example,

     A4 paper is 8.27@dmn{in} wide.

produces

     A4 paper is 8.27in wide.

Not everyone uses this style.  Some people prefer 8.27 in.@: or 8.27 inches to 8.27@dmn{in} in the Texinfo file. In these cases, however, the formatters may insert a line break between the number and the dimension, so use @w (see w).  Also, if you write a period after an abbreviation within a sentence, you should write @: after the period to prevent TeX from inserting extra whitespace, as shown here.  See Inserting Space.

Inserting Accents
=================

Here is a table with the commands Texinfo provides for inserting floating accents.  The commands with non-alphabetic names do not take braces around their argument (which is taken to be the next character). (Exception: @, does take braces around its argument.) This is so as to make the source as convenient to type and read as possible, since accented characters are very common in some languages.

Command                 Output           What
@"o                ö              umlaut accent
@'o                ó              acute accent
@,{c}            ç            cedilla accent
@=o                ō              macron/overbar accent
@^o                ô              circumflex accent
@`o                ò              grave accent
@~o                õ              tilde accent
@dotaccent{o}    ȯ    overdot accent
@H{o}            ő            long Hungarian umlaut
@ringaccent{o}   o̊   ring accent
@tieaccent{oo}   o͡o   tie-after accent
@u{o}            ŏ            breve accent
@ubaraccent{o}   o̱   underbar accent
@udotaccent{o}   ọ   underdot accent
@v{o}            ǒ            hacek or check accent

This table lists the Texinfo commands for inserting other characters commonly used in languages other than English.

@exclamdown{}     ¡     upside-down !
@questiondown{}   ¿   upside-down ?
@aa{},@AA{}    å,Å       A,a with circle
@ae{},@AE{}    æ,Æ       ae,AE ligatures
@dotless{i}       ı       dotless i
@dotless{j}       ȷ       dotless j
@l{},@L{}      ł,Ł         suppressed-L,l
@o{},@O{}      ø,Ø         O,o with slash
@oe{},@OE{}    œ,Œ       OE,oe ligatures
@ss{}             ß             es-zet or sharp S

Inserting Ellipsis, Dots, and Bullets
=====================================

An ellipsis (a line of dots) is not typeset as a string of periods, so a special command is used for ellipsis in Texinfo.  The @bullet command is special, too.  Each of these commands is followed by a pair of braces, {}, without any whitespace between the name of the command and the braces.  (You need to use braces with these commands because you can use them next to other text; without the braces, the formatters would be confused.  See @-Command Syntax, for further information.)

@dots{} (...)
-------------

Use the @dots{} command to generate an ellipsis, which is three dots in a row, appropriately spaced, like this: `...'.  Do not simply write three periods in the input file; that would work for the Info file output, but would produce the wrong amount of space between the periods in the printed manual.

Similarly, the @enddots{} command generates an end-of-sentence ellipsis (four dots) ...

@bullet{} (*)
-------------

Use the @bullet{} command to generate a large round dot, or the closest possible thing to one.  In Info, an asterisk is used.

Here is a bullet: *

When you use @bullet in @itemize, you do not need to type the braces, because @itemize supplies them. (see @itemize.)

Inserting TeX and the Copyright Symbol
======================================

The logo `TeX' is typeset in a special fashion and it needs an @-command.  The copyright symbol, `©', is also special. Each of these commands is followed by a pair of braces, {}, without any whitespace between the name of the command and the braces.

@TeX{} (TeX)
------------

Use the @TeX{} command to generate `TeX'.  In a printed manual, this is a special logo that is different from three ordinary letters.  In Info, it just looks like TeX.  The @TeX{} command is unique among Texinfo commands in that the T and the X are in upper case.

@copyright{} (©)
----------------

Use the @copyright{} command to generate `©'.  In a printed manual, this is a c inside a circle, and in Info, this is (C).

@pounds{} (£): Pounds Sterling
==============================

Use the @pounds{} command to generate `£'.  In a printed manual, this is the symbol for the currency pounds sterling. In Info, it is a #.  Other currency symbols are unfortunately not available.

@minus{} (-): Inserting a Minus Sign
====================================

Use the @minus{} command to generate a minus sign.  In a fixed-width font, this is a single hyphen, but in a proportional font, the symbol is the customary length for a minus sign---a little longer than a hyphen, shorter than an em-dash:

     - is a minus sign generated with @minus{},

     `-' is a hyphen generated with the character -,

     `---' is an em-dash for text.

In the fixed-width font used by Info, @minus{} is the same as a hyphen.

You should not use @minus{} inside @code or @example because the width distinction is not made in the fixed-width font they use.

When you use @minus to specify the mark beginning each entry in an itemized list, you do not need to type the braces (see @itemize.)

@math: Inserting Mathematical Expressions
=========================================

You can write a short mathematical expression with the @math command.  Write the mathematical expression between braces, like this:

     @math{(a + b)(a + b) = a^2 + 2ab + b^2}

This produces the following in Info:

     (a + b)(a + b) = a^2 + 2ab + b^2

Thus, the @math command has no effect on the Info output.

For complex mathematical expressions, you can also use TeX directly (see Raw Formatter Commands).  When you use TeX directly, remember to write the mathematical expression between one or two $ (dollar-signs) as appropriate.

Glyphs for Examples
===================

In Texinfo, code is often illustrated in examples that are delimited by @example and @end example, or by @lisp and @end lisp.  In such examples, you can indicate the results of evaluation or an expansion using => or ==>.  Likewise, there are commands to insert glyphs to indicate printed output, error messages, equivalence of expressions, and the location of point.

The glyph-insertion commands do not need to be used within an example, but most often they are.  Every  glyph-insertion command is followed by a pair of left- and right-hand braces.

Glyphs Summary
--------------

Here are the different glyph commands:

=>
     @result{} points to the result of an expression.

==>
     @expansion{} shows the results of a macro expansion.

-|
     @print{} indicates printed output.

error-->
     @error{} indicates that the following text is an error message.

==
     @equiv{} indicates the exact equivalence of two forms.

-!-
     @point{} shows the location of point.

@result{} (=>): Indicating Evaluation
-------------------------------------

Use the @result{} command to indicate the result of evaluating an expression.

The @result{} command is displayed as => in Info and as a double stemmed arrow in the printed output.

Thus, the following,

     (cdr '(1 2 3))
          => (2 3)

may be read as ``(cdr '(1 2 3)) evaluates to (2 3)''.

@expansion{} (==>): Indicating an Expansion
-------------------------------------------

When an expression is a macro call, it expands into a new expression. You can indicate the result of the expansion with the @expansion{} command.

The @expansion{} command is displayed as ==> in Info and as a long arrow with a flat base in the printed output.

For example, the following

     @lisp
     (third '(a b c))
          @expansion{} (car (cdr (cdr '(a b c))))
          @result{} c
     @end lisp

produces

     (third '(a b c))
          ==> (car (cdr (cdr '(a b c))))
          => c

which may be read as:

     (third '(a b c)) expands to (car (cdr (cdr '(a b c)))); the result of evaluating the expression is c.

Often, as in this case, an example looks better if the @expansion{} and @result{} commands are indented five spaces.

@print{} (-|): Indicating Printed Output
----------------------------------------

Sometimes an expression will print output during its execution.  You can indicate the printed output with the @print{} command.

The @print{} command is displayed as -| in Info and similarly, as a horizontal dash butting against a vertical bar, in the printed output.

In the following example, the printed text is indicated with -|, and the value of the expression follows on the last line.

     (progn (print 'foo) (print 'bar))
          -| foo
          -| bar
          => bar

In a Texinfo source file, this example is written as follows:

     @lisp
     (progn (print 'foo) (print 'bar))
          @print{} foo
          @print{} bar
          @result{} bar
     @end lisp

@error{} (error-->): Indicating an Error Message
------------------------------------------------

A piece of code may cause an error when you evaluate it.  You can designate the error message with the @error{} command.

The @error{} command is displayed as error--> in Info and as the word `error' in a box in the printed output.

Thus,

     @lisp
     (+ 23 'x)
     @error{} Wrong type argument: integer-or-marker-p, x
     @end lisp

produces

     (+ 23 'x)
     error--> Wrong type argument: integer-or-marker-p, x

This indicates that the following error message is printed when you evaluate the expression:

     Wrong type argument: integer-or-marker-p, x

error--> itself is not part of the error message.

@equiv{} (==): Indicating Equivalence
-------------------------------------

Sometimes two expressions produce identical results.  You can indicate the exact equivalence of two forms with the @equiv{} command.

The @equiv{} command is displayed as == in Info and as a three parallel horizontal lines in the printed output.

Thus,

     @lisp
     (make-sparse-keymap) @equiv{} (list 'keymap)
     @end lisp

produces

     (make-sparse-keymap) == (list 'keymap)

This indicates that evaluating (make-sparse-keymap) produces identical results to evaluating (list 'keymap).

@point{} (-!-): Indicating Point in a Buffer
--------------------------------------------

Sometimes you need to show an example of text in an Emacs buffer.  In such examples, the convention is to include the entire contents of the buffer in question between two lines of dashes containing the buffer name.

You can use the @point{} command to show the location of point in the text in the buffer.  (The symbol for point, of course, is not part of the text in the buffer; it indicates the place between two characters where point is located.)

The @point{} command is displayed as -!- in Info and as a small five pointed star in the printed output.

The following example shows the contents of buffer foo before and after evaluating a Lisp command to insert the word changed.

     ---------- Buffer: foo ----------
     This is the -!-contents of foo.
     ---------- Buffer: foo ----------

     (insert "changed ")
          => nil
     ---------- Buffer: foo ----------
     This is the changed -!-contents of foo.
     ---------- Buffer: foo ----------

In a Texinfo source file, the example is written like this:

     @example
     ---------- Buffer: foo ----------
     This is the @point{}contents of foo.
     ---------- Buffer: foo ----------

     (insert "changed ")
          @result{} nil
     ---------- Buffer: foo ----------
     This is the changed @point{}contents of foo.
     ---------- Buffer: foo ----------
     @end example

Inserting Images
================

You can insert an image in an external file with the @image command:

     @image{FILENAME, [WIDTH], [HEIGHT]}

The FILENAME argument is mandatory, and must not have an extension, because the different processors support different formats: TeX reads the file FILENAME.eps (Encapsulated PostScript format); makeinfo uses FILENAME.txt verbatim for Info output (more or less as if it was an @example).  HTML output requires FILENAME.jpg.

The optional WIDTH and HEIGHT arguments specify the size to scale the image to (they are ignored for Info output).  If they are both specified, the image is presented in its natural size (given in the file); if only one is specified, the other is scaled proportionately; and if both are specified, both are respected, thus possibly distorting the original image by changing its aspect ratio.

The WIDTH and HEIGHT may be specified using any valid TeX dimension, namely:

pt
     point (72.27pt = 1in)

pc
     pica (1pc = 12pt)

bp
     big point (72bp = 1in)

in
     inch

cm
     centimeter (2.54cm = 1in)

mm
     millimeter (10mm = 1cm)

dd
     did\^ot point (1157dd = 1238pt)

cc
     cicero (1cc = 12dd)

sp
     scaled point (65536sp = 1pt)

For example, the following will scale a file ridt.eps to one inch vertically, with the width scaled proportionately:

     @image{ridt,,1in}

For @image to work with TeX, the file epsf.tex must be installed somewhere that TeX can find it.  This file is included in the Texinfo distribution and is available from ftp://ftp.tug.org/tex/epsf.tex.

Making and Preventing Breaks
****************************

Usually, a Texinfo file is processed both by TeX and by one of the Info formatting commands.  Line, paragraph, or page breaks sometimes occur in the `wrong' place in one or other form of output.  You must ensure that text looks right both in the printed manual and in the Info file.

For example, in a printed manual, page breaks may occur awkwardly in the middle of an example; to prevent this, you can hold text together using a grouping command that keeps the text from being split across two pages.  Conversely, you may want to force a page break where none would occur normally.  Fortunately, problems like these do not often arise.  When they do, use the break, break prevention, or pagination commands.

The Break Commands
==================

The break commands create or allow line and paragraph breaks:

@*
     Force a line break.

@sp N
     Skip N blank lines.

@-
     Insert a discretionary hyphen.

@hyphenation{HY-PHEN-A-TED WORDS}
     Define hyphen points in HY-PHEN-A-TED WORDS.

The line-break-prevention command holds text together all on one line:

@w{TEXT}
     Prevent TEXT from being split and hyphenated across two lines.

The pagination commands apply only to printed output, since Info files do not have pages.

@page
     Start a new page in the printed manual.

@group
     Hold text together that must appear on one printed page.

@need MILS
     Start a new printed page if not enough space on this one.

@*: Generate Line Breaks
========================

The @* command forces a line break in both the printed manual and in Info.

For example,

     This line @* is broken @*in two places.

produces

     This line
      is broken
     in two places.

(Note that the space after the first @* command is faithfully carried down to the next line.)

The @* command is often used in a file's copyright page:

     This is edition 2.0 of the Texinfo documentation,@*
     and is for ...

In this case, the @* command keeps TeX from stretching the line across the whole page in an ugly manner.

     Please note: Do not write braces after an @* command; they are not needed.

     Do not write an @refill command at the end of a paragraph containing an @* command; it will cause the paragraph to be refilled after the line break occurs, negating the effect of the line break.

@- and @hyphenation: Helping TeX hyphenate
==========================================

Although TeX's hyphenation algorithm is generally pretty good, it does miss useful hyphenation points from time to time.  (Or, far more rarely, insert an incorrect hyphenation.)  So, for documents with an unusual vocabulary or when fine-tuning for a printed edition, you may wish to help TeX out.  Texinfo supports two commands for this:

@-
     Insert a discretionary hyphen, i.e., a place where TeX can (but does not have to) hyphenate.  This is especially useful when you notice an overfull hbox is due to TeX missing a hyphenation (see Overfull hboxes).  TeX will not insert any hyphenation points in a word containing @-.

@hyphenation{HY-PHEN-A-TED WORDS}
     Tell TeX how to hyphenate HY-PHEN-A-TED WORDS.  As shown, you put a - at each hyphenation point.  For example:

          @hyphenation{man-u-script man-u-scripts}

     TeX only uses the specified hyphenation points when the words match exactly, so give all necessary variants.

Info output is not hyphenated, so these commands have no effect there.

@w{TEXT}: Prevent Line Breaks
=============================

@w{TEXT} outputs TEXT and prohibits line breaks within TEXT.

You can use the @w command to prevent TeX from automatically hyphenating a long name or phrase that happens to fall near the end of a line.

     You can copy GNU software from @w{@samp{ftp.gnu.ai.mit.edu}}.

produces

     You can copy GNU software from ftp.gnu.ai.mit.edu.

     Caution: Do not write an @refill command at the end of a paragraph containing an @w command; it will cause the paragraph to be refilled and may thereby negate the effect of the @w command.

@sp N: Insert Blank Lines
=========================

A line beginning with and containing only @sp N generates N blank lines of space in both the printed manual and the Info file.  @sp also forces a paragraph break.  For example,

     @sp 2

generates two blank lines.

The @sp command is most often used in the title page.

@page: Start a New Page
=======================

A line containing only @page starts a new page in a printed manual.  The command has no effect on Info files since they are not paginated.  An @page command is often used in the @titlepage section of a Texinfo file to start the copyright page.

@group: Prevent Page Breaks
===========================

The @group command (on a line by itself) is used inside an @example or similar construct to begin an unsplittable vertical group, which will appear entirely on one page in the printed output. The group is terminated by a line containing only @end group. These two lines produce no output of their own, and in the Info file output they have no effect at all.

Although @group would make sense conceptually in a wide variety of contexts, its current implementation works reliably only within @example and variants, and within @display, @format, @flushleft and @flushright. See Quotations and Examples.  (What all these commands have in common is that each line of input produces a line of output.)  In other contexts, @group can cause anomalous vertical spacing.

This formatting requirement means that you should write:

     @example
     @group
     ...
     @end group
     @end example

with the @group and @end group commands inside the @example and @end example commands.

The @group command is most often used to hold an example together on one page.  In this Texinfo manual, more than 100 examples contain text that is enclosed between @group and @end group.

If you forget to end a group, you may get strange and unfathomable error messages when you run TeX.  This is because TeX keeps trying to put the rest of the Texinfo file onto the one page and does not start to generate error messages until it has processed considerable text.  It is a good rule of thumb to look for a missing @end group if you get incomprehensible error messages in TeX.

@need MILS: Prevent Page Breaks
===============================

A line containing only @need N starts a new page in a printed manual if fewer than N mils (thousandths of an inch) remain on the current page.  Do not use braces around the argument N.  The @need command has no effect on Info files since they are not paginated.

This paragraph is preceded by an @need command that tells TeX to start a new page if fewer than 800 mils (eight-tenths inch) remain on the page.  It looks like this:

     @need 800
     This paragraph is preceded by ...

The @need command is useful for preventing orphans (single lines at the bottoms of printed pages).

Definition Commands
*******************

The @deffn command and the other definition commands enable you to describe functions, variables, macros, commands, user options, special forms and other such artifacts in a uniform format.

In the Info file, a definition causes the entity category---`Function', `Variable', or whatever---to appear at the beginning of the first line of the definition, followed by the entity's name and arguments.  In the printed manual, the command causes TeX to print the entity's name and its arguments on the left margin and print the category next to the right margin.  In both output formats, the body of the definition is indented.  Also, the name of the entity is entered into the appropriate index: @deffn enters the name into the index of functions, @defvr enters it into the index of variables, and so on.

A manual need not and should not contain more than one definition for a given name.  An appendix containing a summary should use @table rather than the definition commands.

The Template for a Definition
=============================

The @deffn command is used for definitions of entities that resemble functions.  To write a definition using the @deffn command, write the @deffn command at the beginning of a line and follow it on the same line by the category of the entity, the name of the entity itself, and its arguments (if any).  Then write the body of the definition on succeeding lines.  (You may embed examples in the body.)  Finally, end the definition with an @end deffn command written on a line of its own.  (The other definition commands follow the same format.)

The template for a definition looks like this:

     @deffn CATEGORY NAME ARGUMENTS...
     BODY-OF-DEFINITION
     @end deffn

For example,

     @deffn Command forward-word count
     This command moves point forward @var{count} words
     (or backward if @var{count} is negative). ...
     @end deffn

produces

      -- Command: forward-word count
          This function moves point forward COUNT words (or backward if COUNT is negative). ...

Capitalize the category name like a title.  If the name of the category contains spaces, as in the phrase `Interactive Command', write braces around it.  For example:

     @deffn {Interactive Command} isearch-forward
     ...
     @end deffn

Otherwise, the second word will be mistaken for the name of the entity.

Some of the definition commands are more general than others.  The @deffn command, for example, is the general definition command for functions and the like---for entities that may take arguments.  When you use this command, you specify the category to which the entity belongs.  The @deffn command possesses three predefined, specialized variations, @defun, @defmac, and @defspec, that specify the category for you: ``Function'', ``Macro'', and ``Special Form'' respectively.  (In Lisp, a special form is an entity much like a function.)  The @defvr command also is accompanied by several predefined, specialized variations for describing particular kinds of variables.

The template for a specialized definition, such as @defun, is similar to the template for a generalized definition, except that you do not need to specify the category:

     @defun NAME ARGUMENTS...
     BODY-OF-DEFINITION
     @end defun

Thus,

     @defun buffer-end flag
     This function returns @code{(point-min)} if @var{flag}
     is less than 1, @code{(point-max)} otherwise.
     ...
     @end defun

produces

      -- Function: buffer-end flag
          This function returns (point-min) if FLAG is less than 1, (point-max) otherwise.  ...

See A Sample Function Definition, for a more detailed example of a function definition, including the use of @example inside the definition.

The other specialized commands work like @defun.

Optional and Repeated Arguments
===============================

Some entities take optional or repeated arguments, which may be specified by a distinctive glyph that uses square brackets and ellipses.  For example, a special form often breaks its argument list into separate arguments in more complicated ways than a straightforward function.

An argument enclosed within square brackets is optional. Thus, [OPTIONAL-ARG] means that OPTIONAL-ARG is optional. An argument followed by an ellipsis is optional and may be repeated more than once. Thus, REPEATED-ARGS... stands for zero or more arguments. Parentheses are used when several arguments are grouped into additional levels of list structure in Lisp.

Here is the @defspec line of an example of an imaginary special form:

      -- Special Form: foobar (VAR [FROM TO [INC]]) BODY...

In this example, the arguments FROM and TO are optional, but must both be present or both absent.  If they are present, INC may optionally be specified as well.  These arguments are grouped with the argument VAR into a list, to distinguish them from BODY, which includes all remaining elements of the form.

In a Texinfo source file, this @defspec line is written like this (except it would not be split over two lines, as it is in this example).

     @defspec foobar (@var{var} [@var{from} @var{to}
          [@var{inc}]]) @var{body}@dots{}

The function is listed in the Command and Variable Index under foobar.

Two or More `First' Lines
=========================

To create two or more `first' or header lines for a definition, follow the first @deffn line by a line beginning with @deffnx. The @deffnx command works exactly like @deffn except that it does not generate extra vertical white space between it and the preceding line.

For example,

     @deffn {Interactive Command} isearch-forward
     @deffnx {Interactive Command} isearch-backward
     These two search commands are similar except ...
     @end deffn

produces

 -- Interactive Command: isearch-forward
 -- Interactive Command: isearch-backward
     These two search commands are similar except ...

Each of the other definition commands has an `x' form: @defunx, @defvrx, @deftypefunx, etc.

The `x' forms work just like @itemx; see @itemx.

The Definition Commands
=======================

Texinfo provides more than a dozen definition commands, all of which are described in this section.

The definition commands automatically enter the name of the entity in the appropriate index: for example, @deffn, @defun, and @defmac enter function names in the index of functions; @defvr and @defvar enter variable names in the index of variables.

Although the examples that follow mostly illustrate Lisp, the commands can be used for other programming languages.

Functions and Similar Entities
------------------------------

This section describes the commands for describing functions and similar entities:

@deffn CATEGORY NAME ARGUMENTS...
     The @deffn command is the general definition command for functions, interactive commands, and similar entities that may take arguments.  You must choose a term to describe the category of entity being defined; for example, ``Function'' could be used if the entity is a function.  The @deffn command is written at the beginning of a line and is followed on the same line by the category of entity being described, the name of this particular entity, and its arguments, if any.  Terminate the definition with @end deffn on a line of its own.

     For example, here is a definition:

          @deffn Command forward-char nchars
          Move point forward @var{nchars} characters.
          @end deffn

     This shows a rather terse definition for a ``command'' named forward-char with one argument, NCHARS.

     @deffn prints argument names such as NCHARS in italics or upper case, as if @var had been used, because we think of these names as metasyntactic variables---they stand for the actual argument values.  Within the text of the description, write an argument name explicitly with @var to refer to the value of the argument.  In the example above, we used @var{nchars} in this way.

     The template for @deffn is:

          @deffn CATEGORY NAME ARGUMENTS...
          BODY-OF-DEFINITION
          @end deffn

@defun NAME ARGUMENTS...
     The @defun command is the definition command for functions. @defun is equivalent to @deffn Function ....

     For example,

          @defun set symbol new-value
          Change the value of the symbol @var{symbol}
          to @var{new-value}.
          @end defun

     shows a rather terse definition for a function set whose arguments are SYMBOL and NEW-VALUE.  The argument names on the @defun line automatically appear in italics or upper case as if they were enclosed in @var.  Terminate the definition with @end defun on a line of its own.

     The template is:

          @defun FUNCTION-NAME ARGUMENTS...
          BODY-OF-DEFINITION
          @end defun

     @defun creates an entry in the index of functions.

@defmac NAME ARGUMENTS...
     The @defmac command is the definition command for macros. @defmac is equivalent to @deffn Macro ... and works like @defun.

@defspec NAME ARGUMENTS...
     The @defspec command is the definition command for special forms.  (In Lisp, a special form is an entity much like a function, see Special Forms (GNU Emacs Lisp Reference Manual).) @defspec is equivalent to @deffn {Special Form} ... and works like @defun.

Variables and Similar Entities
------------------------------

Here are the commands for defining variables and similar entities:

@defvr CATEGORY NAME
     The @defvr command is a general definition command for something like a variable---an entity that records a value.  You must choose a term to describe the category of entity being defined; for example, ``Variable'' could be used if the entity is a variable. Write the @defvr command at the beginning of a line and followed it on the same line by the category of the entity and the name of the entity.

     Capitalize the category name like a title.  If the name of the category contains spaces, as in the name ``User Option'', enclose it in braces. Otherwise, the second word will be mistaken for the name of the entity. For example,

          @defvr {User Option} fill-column
          This buffer-local variable specifies
          the maximum width of filled lines.
          ...
          @end defvr

     Terminate the definition with @end defvr on a line of its own.

     The template is:

          @defvr CATEGORY NAME
          BODY-OF-DEFINITION
          @end defvr

     @defvr creates an entry in the index of variables for NAME.

@defvar NAME
     The @defvar command is the definition command for variables. @defvar is equivalent to @defvr Variable ....

     For example:

          @defvar kill-ring
          ...
          @end defvar

     The template is:

          @defvar NAME
          BODY-OF-DEFINITION
          @end defvar

     @defvar creates an entry in the index of variables for NAME.

@defopt NAME
     The @defopt command is the definition command for user options, i.e., variables intended for users to change according to taste; Emacs has many such (see Variables (The GNU Emacs Manual)).  @defopt is equivalent to @defvr {User Option} ... and works like @defvar.

Functions in Typed Languages
----------------------------

The @deftypefn command and its variations are for describing functions in languages in which you must declare types of variables and functions, such as C and C++.

@deftypefn CATEGORY DATA-TYPE NAME ARGUMENTS...
     The @deftypefn command is the general definition command for functions and similar entities that may take arguments and that are typed.  The @deftypefn command is written at the beginning of a line and is followed on the same line by the category of entity being described, the type of the returned value, the name of this particular entity, and its arguments, if any.

     For example,

          @deftypefn {Library Function} int foobar
             (int @var{foo}, float @var{bar})
          ...
          @end deftypefn

     (where the text before the ``...'', shown above as two lines, would actually be a single line in a real Texinfo file) produces the following in Info:

          -- Library Function: int foobar (int FOO, float BAR)
          ...

     This means that foobar is a ``library function'' that returns an int, and its arguments are FOO (an int) and BAR (a float).

     The argument names that you write in @deftypefn are not subject to an implicit @var---since the actual names of the arguments in @deftypefn are typically scattered among data type names and keywords, Texinfo cannot find them without help.  Instead, you must write @var explicitly around the argument names.  In the example above, the argument names are foo and bar.

     The template for @deftypefn is:

          @deftypefn CATEGORY DATA-TYPE NAME ARGUMENTS ...
          BODY-OF-DESCRIPTION
          @end deftypefn

     Note that if the CATEGORY or DATA TYPE is more than one word then it must be enclosed in braces to make it a single argument.

     If you are describing a procedure in a language that has packages, such as Ada, you might consider using @deftypefn in a manner somewhat contrary to the convention described in the preceding paragraphs.

     For example:

          @deftypefn stacks private push
                  (@var{s}:in out stack;
                  @var{n}:in integer)
          ...
          @end deftypefn

     (The @deftypefn arguments are shown split into three lines, but would be a single line in a real Texinfo file.)

     In this instance, the procedure is classified as belonging to the package stacks rather than classified as a `procedure' and its data type is described as private.  (The name of the procedure is push, and its arguments are S and N.)

     @deftypefn creates an entry in the index of functions for NAME.

@deftypefun DATA-TYPE NAME ARGUMENTS...
     The @deftypefun command is the specialized definition command for functions in typed languages.  The command is equivalent to @deftypefn Function ....

     Thus,

          @deftypefun int foobar (int @var{foo}, float @var{bar})
          ...
          @end deftypefun

     produces the following in Info:

          -- Function: int foobar (int FOO, float BAR)
          ...

     The template is:

          @deftypefun TYPE NAME ARGUMENTS...
          BODY-OF-DESCRIPTION
          @end deftypefun

     @deftypefun creates an entry in the index of functions for NAME.

@deftypemethod CLASS DATA-TYPE METHOD-NAME ARGUMENTS...
     The @deftypemethod command is the definition command for methods in object-oriented typed languages, such as C++ and Java.  It is similar to the @deftypefn with the addition of the CLASS parameter to specify the class containing the method.

Variables in Typed Languages
----------------------------

Variables in typed languages are handled in a manner similar to functions in typed languages.  See Typed Functions.  The general definition command @deftypevr corresponds to @deftypefn and the specialized definition command @deftypevar corresponds to @deftypefun.

@deftypevr CATEGORY DATA-TYPE NAME
     The @deftypevr command is the general definition command for something like a variable in a typed language---an entity that records a value.  You must choose a term to describe the category of the entity being defined; for example, ``Variable'' could be used if the entity is a variable.

     The @deftypevr command is written at the beginning of a line and is followed on the same line by the category of the entity being described, the data type, and the name of this particular entity.

     For example:

          @deftypevr {Global Flag} int enable
          ...
          @end deftypevr

     produces the following in Info:

          -- Global Flag: int enable
          ...

     The template is:

          @deftypevr CATEGORY DATA-TYPE NAME
          BODY-OF-DESCRIPTION
          @end deftypevr

     @deftypevr creates an entry in the index of variables for NAME.

@deftypevar DATA-TYPE NAME
     The @deftypevar command is the specialized definition command for variables in typed languages.  @deftypevar is equivalent to @deftypevr Variable ....

     For example:

          @deftypevar int fubar
          ...
          @end deftypevar

     produces the following in Info:

          -- Variable: int fubar
          ...

     The template is:

          @deftypevar DATA-TYPE NAME
          BODY-OF-DESCRIPTION
          @end deftypevar

     @deftypevar creates an entry in the index of variables for NAME.

Object-Oriented Programming
---------------------------

Here are the commands for formatting descriptions about abstract objects, such as are used in object-oriented programming.  A class is a defined type of abstract object.  An instance of a class is a particular object that has the type of the class.  An instance variable is a variable that belongs to the class but for which each instance has its own value.

In a definition, if the name of a class is truly a name defined in the programming system for a class, then you should write an @code around it.  Otherwise, it is printed in the usual text font.

@defcv CATEGORY CLASS NAME
     The @defcv command is the general definition command for variables associated with classes in object-oriented programming.  The @defcv command is followed by three arguments: the category of thing being defined, the class to which it belongs, and its name.  Thus,

          @defcv {Class Option} Window border-pattern
          ...
          @end defcv

     illustrates how you would write the first line of a definition of the border-pattern class option of the class Window.

     The template is

          @defcv CATEGORY CLASS NAME
          ...
          @end defcv

     @defcv creates an entry in the index of variables.

@defivar CLASS NAME
     The @defivar command is the definition command for instance variables in object-oriented programming.  @defivar is equivalent to @defcv {Instance Variable} ...

     The template is:

          @defivar CLASS INSTANCE-VARIABLE-NAME
          BODY-OF-DEFINITION
          @end defivar

     @defivar creates an entry in the index of variables.

@defop CATEGORY CLASS NAME ARGUMENTS...
     The @defop command is the general definition command for entities that may resemble methods in object-oriented programming. These entities take arguments, as functions do, but are associated with particular classes of objects.

     For example, some systems have constructs called wrappers that are associated with classes as methods are, but that act more like macros than like functions.  You could use @defop Wrapper to describe one of these.

     Sometimes it is useful to distinguish methods and operations. You can think of an operation as the specification for a method. Thus, a window system might specify that all window classes have a method named expose; we would say that this window system defines an expose operation on windows in general.  Typically, the operation has a name and also specifies the pattern of arguments; all methods that implement the operation must accept the same arguments, since applications that use the operation do so without knowing which method will implement it.

     Often it makes more sense to document operations than methods.  For example, window application developers need to know about the expose operation, but need not be concerned with whether a given class of windows has its own method to implement this operation. To describe this operation, you would write:

          @defop Operation windows expose

     The @defop command is written at the beginning of a line and is followed on the same line by the overall name of the category of operation, the name of the class of the operation, the name of the operation, and its arguments, if any.

     The template is:

          @defop CATEGORY CLASS NAME ARGUMENTS...
          BODY-OF-DEFINITION
          @end defop

     @defop creates an entry, such as `expose on windows', in the index of functions.

@defmethod CLASS NAME ARGUMENTS...
     The @defmethod command is the definition command for methods in object-oriented programming.  A method is a kind of function that implements an operation for a particular class of objects and its subclasses.  In the Lisp Machine, methods actually were functions, but they were usually defined with defmethod.

     @defmethod is equivalent to @defop Method .... The command is written at the beginning of a line and is followed by the name of the class of the method, the name of the method, and its arguments, if any.

     For example,

          @defmethod bar-class bar-method argument
          ...
          @end defmethod

     illustrates the definition for a method called bar-method of the class bar-class.  The method takes an argument.

     The template is:

          @defmethod CLASS METHOD-NAME ARGUMENTS...
          BODY-OF-DEFINITION
          @end defmethod

     @defmethod creates an entry, such as `bar-method on bar-class', in the index of functions.

@deftypemethod CLASS DATA-TYPE NAME ARGUMENTS...
     The @deftypemethod command is the definition command for methods in object-oriented typed languages, such as C++ and Java.  It is similar to the @defmethod command with the addition of the DATA-TYPE parameter to specify the return type of the method.

Data Types
----------

Here is the command for data types:

@deftp CATEGORY NAME ATTRIBUTES...
     The @deftp command is the generic definition command for data types.  The command is written at the beginning of a line and is followed on the same line by the category, by the name of the type (which is a word like int or float), and then by names of attributes of objects of that type.  Thus, you could use this command for describing int or float, in which case you could use data type as the category.  (A data type is a category of certain objects for purposes of deciding which operations can be performed on them.)

     In Lisp, for example,  pair names a particular data type, and an object of that type has two slots called the CAR and the CDR.  Here is how you would write the first line of a definition of pair.

          @deftp {Data type} pair car cdr
          ...
          @end deftp

     The template is:

          @deftp CATEGORY NAME-OF-TYPE ATTRIBUTES...
          BODY-OF-DEFINITION
          @end deftp

     @deftp creates an entry in the index of data types.

Conventions for Writing Definitions
===================================

When you write a definition using @deffn, @defun, or one of the other definition commands, please take care to use arguments that indicate the meaning, as with the COUNT argument to the forward-word function.  Also, if the name of an argument contains the name of a type, such as INTEGER, take care that the argument actually is of that type.

A Sample Function Definition
============================

A function definition uses the @defun and @end defun commands.  The name of the function follows immediately after the @defun command and it is followed, on the same line, by the parameter list.

Here is a definition from Calling Functions (The GNU Emacs Lisp Reference Manual).

      -- Function: apply function &rest arguments
          apply calls FUNCTION with ARGUMENTS, just like funcall but with one difference: the last of ARGUMENTS is a list of arguments to give to FUNCTION, rather than a single argument.  We also say that this list is appended to the other arguments.

          apply returns the result of calling FUNCTION. As with funcall, FUNCTION must either be a Lisp function or a primitive function; special forms and macros do not make sense in apply.

               (setq f 'list)
                    => list
               (apply f 'x 'y 'z)
               error--> Wrong type argument: listp, z
               (apply '+ 1 2 '(3 4))
                    => 10
               (apply '+ '(1 2 3 4))
                    => 10

               (apply 'append '((a b c) nil (x y z) nil))
                    => (a b c x y z)

          An interesting example of using apply is found in the description of mapcar.

In the Texinfo source file, this example looks like this:

     @defun apply function &rest arguments

     @code{apply} calls @var{function} with
     @var{arguments}, just like @code{funcall} but with one
     difference: the last of @var{arguments} is a list of
     arguments to give to @var{function}, rather than a single
     argument.  We also say that this list is @dfn{appended}
     to the other arguments.

     @code{apply} returns the result of calling
     @var{function}.  As with @code{funcall},
     @var{function} must either be a Lisp function or a
     primitive function; special forms and macros do not make
     sense in @code{apply}.

     @example
     (setq f 'list)
          @result{} list
     (apply f 'x 'y 'z)
     @error{} Wrong type argument: listp, z
     (apply '+ 1 2 '(3 4))
          @result{} 10
     (apply '+ '(1 2 3 4))
          @result{} 10

     (apply 'append '((a b c) nil (x y z) nil))
          @result{} (a b c x y z)
     @end example

     An interesting example of using @code{apply} is found
     in the description of @code{mapcar}.@refill
     @end defun

In this manual, this function is listed in the Command and Variable Index under apply.

Ordinary variables and user options are described using a format like that for functions except that variables do not take arguments.

Footnotes
*********

A footnote is for a reference that documents or elucidates the primary text. (A footnote should complement or expand upon the primary text, but a reader should not need to read a footnote to understand the primary text.  For a thorough discussion of footnotes, see The Chicago Manual of Style, which is published by the University of Chicago Press.)

Footnote Commands
=================

In Texinfo, footnotes are created with the @footnote command. This command is followed immediately by a left brace, then by the text of the footnote, and then by a terminating right brace.  Footnotes may be of any length (they will be broken across pages if necessary), but are usually short.  The template is:

     ordinary text@footnote{TEXT OF FOOTNOTE}

As shown here, the @footnote command should come right after the text being footnoted, with no intervening space; otherwise, the formatters the footnote mark might end up starting up a line.

For example, this clause is followed by a sample footnote (Here is the sample footnote.); in the Texinfo source, it looks like this:

     ...a sample footnote@footnote{Here is the sample
     footnote.}; in the Texinfo source...

Warning: Don't use footnotes in the argument of the @item command for a @table table.  This doesn't work, and because of limitations of TeX, there is no way to fix it.  You must put the footnote into the body text of the table.

In a printed manual or book, the reference mark for a footnote is a small, superscripted number; the text of the footnote appears at the bottom of the page, below a horizontal line.

In Info, the reference mark for a footnote is a pair of parentheses with the footnote number between them, like this: (1).

Footnote Styles
===============

Info has two footnote styles, which determine where the text of the footnote is located:

  * In the `End' node style, all the footnotes for a single node are placed at the end of that node.  The footnotes are separated from the rest of the node by a line of dashes with the word Footnotes within it.  Each footnote begins with an (N) reference mark.

     Here is an example of a single footnote in the end of node style:

           --------- Footnotes ---------

          (1)  Here is a sample footnote.

  * In the `Separate' node style, all the footnotes for a single node are placed in an automatically constructed node of their own.  In this style, a ``footnote reference'' follows each (N) reference mark in the body of the node.  The footnote reference is actually a cross reference which you use to reach the footnote node.

     The name of the node containing the footnotes is constructed by appending -Footnotes to the name of the node that contains the footnotes. (Consequently, the footnotes' node for the Footnotes node is Footnotes-Footnotes!)  The footnotes' node has an `Up' node pointer that leads back to its parent node.

     Here is how the first footnote in this manual looks after being formatted for Info in the separate node style:

          File: texinfo.info  Node: Overview-Footnotes, Up: Overview

          (1) Note that the first syllable of "Texinfo" is
          pronounced like "speck", not "hex". ...

A Texinfo file may be formatted into an Info file with either footnote style.

Use the @footnotestyle command to specify an Info file's footnote style.  Write this command at the beginning of a line followed by an argument, either end for the end node style or separate for the separate node style.

For example,

     @footnotestyle end

or

     @footnotestyle separate

Write an @footnotestyle command before or shortly after the end-of-header line at the beginning of a Texinfo file.  (If you include the @footnotestyle command between the start-of-header and end-of-header lines, the region formatting commands will format footnotes as specified.)

If you do not specify a footnote style, the formatting commands use their default style.  Currently, texinfo-format-buffer and texinfo-format-region use the `separate' style and makeinfo uses the `end' style.

This chapter contains two footnotes.

Conditionally Visible Text
**************************

Sometimes it is good to use different text for a printed manual and its corresponding Info file.  In this case, you can use the conditional commands to specify which text is for the printed manual and which is for the Info file.

Conditional Commands
====================

@ifinfo begins segments of text that should be ignored by TeX when it typesets the printed manual.  The segment of text appears only in the Info file. The @ifinfo command should appear on a line by itself;  end the Info-only text with a line containing @end ifinfo by itself.  At the beginning of a Texinfo file, the Info permissions are contained within a region marked by @ifinfo and @end ifinfo. (see Info Summary and Permissions.)

The @iftex and @end iftex commands are similar to the @ifinfo and @end ifinfo commands, except that they specify text that will appear in the printed manual but not in the Info file.  Likewise for @ifhtml and @end ifhtml, which specify text to appear only in HTML output.

For example,

     @iftex
     This text will appear only in the printed manual.
     @end iftex
     @ifinfo
     However, this text will appear only in Info.
     @end ifinfo

The preceding example produces the following line: However, this text will appear only in Info.

Note how you only see one of the two lines, depending on whether you are reading the Info version or the printed version of this manual.

The @titlepage command is a special variant of @iftex that is used for making the title and copyright pages of the printed manual.  (see @titlepage.)

Conditional Not Commands
========================

You can specify text to be included in any output format other than some given one with the @ifnot... commands:

     @ifnothtml ... @end ifnothtml
     @ifnotinfo ... @end ifnotinfo
     @ifnottex ... @end ifnottex

(The @ifnot... command and the @end command must actually appear on lines by themselves.)

If the output file is not being made for the given format, the region is included.  Otherwise, it is ignored.

The regions delimited by these commands are ordinary Texinfo source as with @iftex, not raw formatter source as with @tex.

Raw Formatter Commands
======================

Inside a region delineated by @iftex and @end iftex, you can embed some raw TeX commands.  Info will ignore these commands since they are only in that part of the file which is seen by TeX. You can write the TeX commands as you would write them in a normal TeX file, except that you must replace the \ used by TeX with an @.  For example, in the @titlepage section of a Texinfo file, you can use the TeX command @vskip to format the copyright page.  (The @titlepage command causes Info to ignore the region automatically, as it does with the @iftex command.)

However, many features of plain TeX will not work, as they are overridden by Texinfo features.

You can enter plain TeX completely, and use \ in the TeX commands, by delineating a region with the @tex and @end tex commands.  (The @tex command also causes Info to ignore the region, like the @iftex command.)  The sole exception is that @ chracter still introduces a command, so that @end tex can be recognized properly.

For example, here is a mathematical expression written in plain TeX:

     @tex
     $$ \chi^2 = \sum_{i=1}^N
               \left (y_i - (a + b x_i)
               \over \sigma_i\right)^2 $$
     @end tex

The output of this example will appear only in a printed manual.  If you are reading this in Info, you will not see the equation that appears in the printed manual.

Analogously, you can use @ifhtml ... @end ifhtml to delimit a region to be included in HTML output only, and @html ... @end ifhtml for a region of raw HTML (again, except that @ is still the escape character, so the @end command can be recognized.)

@set, @clear, and @value
========================

You can direct the Texinfo formatting commands to format or ignore parts of a Texinfo file with the @set, @clear, @ifset, and @ifclear commands.

In addition, you can use the @set FLAG command to set the value of FLAG to a string of characters; and use @value{FLAG} to insert that string.  You can use @set, for example, to set a date and use @value to insert the date in several places in the Texinfo file.

@ifset and @ifclear
-------------------

When a FLAG is set, the Texinfo formatting commands format text between subsequent pairs of @ifset FLAG and @end ifset commands.  When the FLAG is cleared, the Texinfo formatting commands do not format the text.

Use the @set FLAG command to turn on, or set, a FLAG; a flag can be any single word.  The format for the command looks like this:

     @set FLAG

Write the conditionally formatted text between @ifset FLAG and @end ifset commands, like this:

     @ifset FLAG
     CONDITIONAL-TEXT
     @end ifset

For example, you can create one document that has two variants, such as a manual for a `large' and `small' model:

     You can use this machine to dig up shrubs
     without hurting them.

     @set large

     @ifset large
     It can also dig up fully grown trees.
     @end ifset

     Remember to replant promptly ...

In the example, the formatting commands will format the text between @ifset large and @end ifset because the large flag is set.

Use the @clear FLAG command to turn off, or clear, a flag.  Clearing a flag is the opposite of setting a flag.  The command looks like this:

     @clear FLAG

Write the command on a line of its own.

When FLAG is cleared, the Texinfo formatting commands do not format the text between @ifset FLAG and @end ifset; that text is ignored and does not appear in either printed or Info output.

For example, if you clear the flag of the preceding example by writing an @clear large command after the @set large command (but before the conditional text), then the Texinfo formatting commands ignore the text between the @ifset large and @end ifset commands.  In the formatted output, that text does not appear; in both printed and Info output, you see only the lines that say, ``You can use this machine to dig up shrubs without hurting them.  Remember to replant promptly ...''.

If a flag is cleared with an @clear FLAG command, then the formatting commands format text between subsequent pairs of @ifclear and @end ifclear commands.  But if the flag is set with @set FLAG, then the formatting commands do not format text between an @ifclear and an @end ifclear command; rather, they ignore that text.  An @ifclear command looks like this:

     @ifclear FLAG

In brief, the commands are:

@set FLAG
     Tell the Texinfo formatting commands that FLAG is set.

@clear FLAG
     Tell the Texinfo formatting commands that FLAG is cleared.

@ifset FLAG
     If FLAG is set, tell the Texinfo formatting commands to format the text up to the following @end ifset command.

     If FLAG is cleared, tell the Texinfo formatting commands to ignore text up to the following @end ifset command.

@ifclear FLAG
     If FLAG is set, tell the Texinfo formatting commands to ignore the text up to the following @end ifclear command.

     If FLAG is cleared, tell the Texinfo formatting commands to format the text up to the following @end ifclear command.

@value
------

You can use the @set command to specify a value for a flag, which is expanded by the @value command.  The value is a string a characters.

Write the @set command like this:

     @set foo This is a string.

This sets the value of foo to ``This is a string.''

The Texinfo formatters replace an @value{FLAG} command with the string to which FLAG is set.

Thus, when foo is set as shown above, the Texinfo formatters convert

     @value{foo}
     to
     This is a string.

You can write an @value command within a paragraph; but you must write an @set command on a line of its own.

If you write the @set command like this:

     @set foo

without specifying a string, the value of foo is an empty string.

If you clear a previously set flag with an @clear FLAG command, a subsequent @value{flag} command is invalid and the string is replaced with an error message that says {No value for "FLAG"}.

For example, if you set foo as follows:

     @set how-much very, very, very

then the formatters transform

     It is a @value{how-much} wet day.
     into
     It is a very, very, very wet day.

If you write

     @clear how-much

then the formatters transform

     It is a @value{how-much} wet day.
     into
     It is a {No value for "how-much"} wet day.

@value Example
--------------

You can use the @value command to limit the number of places you need to change when you record an update to a manual. Here is how it is done in The GNU Make Manual:

Set the flags:

     @set EDITION 0.35 Beta
     @set VERSION 3.63 Beta
     @set UPDATED 14 August 1992
     @set UPDATE-MONTH August 1992

Write text for the first @ifinfo section, for people reading the Texinfo file:

     This is Edition @value{EDITION},
     last updated @value{UPDATED},
     of @cite{The GNU Make Manual},
     for @code{make}, Version @value{VERSION}.

Write text for the title page, for people reading the printed manual:

     @title GNU Make
     @subtitle A Program for Directing Recompilation
     @subtitle Edition @value{EDITION}, ...
     @subtitle @value{UPDATE-MONTH}

(On a printed cover, a date listing the month and the year looks less fussy than a date listing the day as well as the month and year.)

Write text for the Top node, for people reading the Info file:

     This is Edition @value{EDITION}
     of the @cite{GNU Make Manual},
     last updated @value{UPDATED}
     for @code{make} Version @value{VERSION}.

After you format the manual, the text in the first @ifinfo section looks like this:

     This is Edition 0.35 Beta, last updated 14 August 1992,
     of `The GNU Make Manual', for `make', Version 3.63 Beta.

When you update the manual, change only the values of the flags; you do not need to rewrite the three sections.

Macros: Defining New Texinfo Commands
*************************************

A Texinfo macro allows you to define a new Texinfo command as any sequence of text and/or existing commands (including other macros).  The macro can have any number of parameters---text you supply each time you use the macro.  (This has nothing to do with the @defmac command, which is for documenting macros in the subject of the manual; see Def Cmd Template.)

Defining Macros
===============

You use the Texinfo @macro command to define a macro.  For example:

     @macro MACRO-NAME{PARAM1, PARAM2, ...}
     TEXT ... \PARAM1\ ...
     @end macro

The parameters PARAM1, PARAM2, ... correspond to arguments supplied when the macro is subsequently used in the document (see the next section).

If a macro needs no parameters, you can define it either with an empty list (@macro foo {}) or with no braces at all (@macro foo).

The definition or body of the macro can contain any Texinfo commands, including previously-defined macros.  (It is not possible to have mutually recursive Texinfo macros.)  In the body, instances of a parameter name surrounded by backslashes, as in \PARAM1\ in the example above, are replaced by the corresponding argument from the macro invocation.

You can undefine a macro FOO with @unmacro FOO. It is not an error to undefine a macro that is already undefined. For example:

     @unmacro foo

Invoking Macros
===============

After a macro is defined (see the previous section), you can use (invoke) it in your document like this:

     @MACRO-NAME {ARG1, ARG2, ...}

and the result will be just as if you typed the body of MACRO-NAME at that spot.  For example:

     @macro foo {p, q}
     Together: \p\ & \q\.
     @end macro
     @foo{a, b}

produces:

     Together: a & b.

Thus, the arguments and parameters are separated by commas and delimited by braces; any whitespace after (but not before) a comma is ignored.  To insert a comma, brace, or backslash in an argument, prepend a backslash, as in

     @MACRO-NAME {\\\{\}\,}

which will pass the (almost certainly error-producing) argument \{}, to MACRO-NAME.

If the macro is defined to take a single argument, and is invoked without any braces, the entire rest of the line after the macro name is supplied as the argument.  For example:

     @macro bar {p}
     Twice: \p\, \p\.
     @end macro
     @bar aah

produces:

     Twice: aah, aah.

Format and Print Hardcopy
*************************

There are three major shell commands for making a printed manual from a Texinfo file: one for converting the Texinfo file into a file that will be printed, a second for sorting indices, and a third for printing the formatted document.  When you use the shell commands, you can either work directly in the operating system shell or work within a shell inside GNU Emacs.

If you are using GNU Emacs, you can use commands provided by Texinfo mode instead of shell commands.  In addition to the three commands to format a file, sort the indices, and print the result, Texinfo mode offers key bindings for commands to recenter the output buffer, show the print queue, and delete a job from the print queue.

Use TeX
=======

The typesetting program called TeX is used for formatting a Texinfo file.  TeX is a very powerful typesetting program and, if used right, does an exceptionally good job.  (see How to Obtain TeX, for information on how to obtain TeX.)

The makeinfo, texinfo-format-region, and texinfo-format-buffer commands read the very same @-commands in the Texinfo file as does TeX, but process them differently to make an Info file; see Create an Info File.

Format using tex and texindex
=============================

Format the Texinfo file with the shell command tex followed by the name of the Texinfo file.  For example:

     tex foo.texi

TeX will produce a DVI file as well as several auxiliary files containing information for indices, cross references, etc.  The DVI file (for DeVice Independent file) can be printed on virtually any printe (see the following sections).

The tex formatting command itself does not sort the indices; it writes an output file of unsorted index data.  (The texi2dvi command automatically generates indices; see Format using texi2dvi.)  To generate a printed index after running the tex command, you first need a sorted index to work from.  The texindex command sorts indices.  (The source file texindex.c comes as part of the standard Texinfo distribution, among other places.)

The tex formatting command outputs unsorted index files under names that obey a standard convention: the name of your main input file with any .tex (or similar, see tex invocation (Web2c)) extension removed, followed by the two letter names of indices. For example, the raw index output files for the input file foo.texinfo would be foo.cp, foo.vr, foo.fn, foo.tp, foo.pg and foo.ky.  Those are exactly the arguments to give to texindex.

Instead of specifying all the unsorted index file names explicitly, you can use ?? as shell wildcards and give the command in this form:

     texindex foo.??

This command will run texindex on all the unsorted index files, including any that you have defined yourself using @defindex or @defcodeindex.  (You may execute texindex foo.?? even if there are similarly named files with two letter extensions that are not index files, such as foo.el.  The texindex command reports but otherwise ignores such files.)

For each file specified, texindex generates a sorted index file whose name is made by appending s to the input file name.  The @printindex command knows to look for a file of that name (see Printing Indices & Menus).  texindex does not alter the raw index output file.

After you have sorted the indices, you need to rerun the tex formatting command on the Texinfo file.  This regenerates the DVI file, this time with up-to-date index entries.

Finally, you may need to run tex one more time, to get the page numbers in the cross-references correct.

To summarize, this is a four step process:

 1. Run tex on your Texinfo file.  This generates a DVI file (with undefined cross-references and no indices), and the raw index files (with two letter extensions).

 2. Run texindex on the raw index files.  This creates the corresponding sorted index files (with three letter extensions).

 3. Run tex again on your Texinfo file.  This regenerates the DVI file, this time with indices and defined cross-references, but with page numbers for the cross-references from last time, generally incorrect.

 4. Run tex one last time.  This time the correct page numbers are written for the cross-references.

Alternatively, it's a one-step process: run texi2dvi.

You need not run texindex each time after you run tex.  If you do not, on the next run, the tex formatting command will use whatever sorted index files happen to exist from the previous use of texindex.  This is usually ok while you are debugging.

Format using texi2dvi
=====================

The texi2dvi command is a shell script that automatically runs both tex and texindex as many times as necessary to produce a DVI file with up-to-date, sorted indices.  It simplifies the tex---texindex---tex sequence described in the previous section.

The syntax for texi2dvi is like this (where prompt$ is the shell prompt):

     prompt$ texi2dvi FILENAME...

Shell Print Using lpr -d
========================

The precise command to print a DVI file depends on your system installation, but lpr -d is common.  The command may require the DVI file name without any extension or with a .dvi extension.  (If it is lpr, you must include the .dvi.)

The following commands, for example, will (probably) suffice to sort the indices, format, and print the Bison Manual:

     tex bison.texinfo
     texindex bison.??
     tex bison.texinfo
     lpr -d bison.dvi

(Remember that the shell commands may be different at your site; but these are commonly used versions.)

Using the texi2dvi shell script, you simply need type:

     texi2dvi bison.texinfo
     lpr -d bison.dvi

From an Emacs Shell
===================

You can give formatting and printing commands from a shell within GNU Emacs.  To create a shell within Emacs, type M-x shell.  In this shell, you can format and print the document.  See Format and Print Hardcopy, for details.

You can switch to and from the shell buffer while tex is running and do other editing.  If you are formatting a long document on a slow machine, this can be very convenient.

You can also use texi2dvi from an Emacs shell.  For example, here is how to use texi2dvi to format and print Using and Porting GNU CC from a shell within Emacs:

     texi2dvi gcc.texinfo
     lpr -d gcc.dvi

See Texinfo Mode Printing, for more information about formatting and printing in Texinfo mode.

Formatting and Printing in Texinfo Mode
=======================================

Texinfo mode provides several predefined key commands for TeX formatting and printing.  These include commands for sorting indices, looking at the printer queue, killing the formatting job, and recentering the display of the buffer in which the operations occur.

C-c C-t C-b
M-x texinfo-tex-buffer
     Run texi2dvi on the current buffer.

C-c C-t C-r
M-x texinfo-tex-region
     Run TeX on the current region.

C-c C-t C-i
M-x texinfo-texindex
     Sort the indices of a Texinfo file formatted with texinfo-tex-region.

C-c C-t C-p
M-x texinfo-tex-print
     Print a DVI file that was made with texinfo-tex-region or texinfo-tex-buffer.

C-c C-t C-q
M-x tex-show-print-queue
     Show the print queue.

C-c C-t C-d
M-x texinfo-delete-from-print-queue
     Delete a job from the print queue; you will be prompted for the job number shown by a preceding C-c C-t C-q command (texinfo-show-tex-print-queue).

C-c C-t C-k
M-x tex-kill-job
     Kill the currently running TeX job started by texinfo-tex-region or texinfo-tex-buffer, or any other process running in the Texinfo shell buffer.

C-c C-t C-x
M-x texinfo-quit-job
     Quit a TeX formatting job that has stopped because of an error by sending an x to it.  When you do this, TeX preserves a record of what it did in a .log file.

C-c C-t C-l
M-x tex-recenter-output-buffer
     Redisplay the shell buffer in which the TeX printing and formatting commands are run to show its most recent output.

Thus, the usual sequence of commands for formatting a buffer is as follows (with comments to the right):

     C-c C-t C-b             Run texi2dvi on the buffer.
     C-c C-t C-p             Print the DVI file.
     C-c C-t C-q             Display the printer queue.

The Texinfo mode TeX formatting commands start a subshell in Emacs called the *tex-shell*.  The texinfo-tex-command, texinfo-texindex-command, and tex-dvi-print-command commands are all run in this shell.

You can watch the commands operate in the *tex-shell* buffer, and you can switch to and from and use the *tex-shell* buffer as you would any other shell buffer.

The formatting and print commands depend on the values of several variables. The default values are:

          Variable                              Default value

     texinfo-texi2dvi-command                  "texi2dvi"
     texinfo-tex-command                       "tex"
     texinfo-texindex-command                  "texindex"
     texinfo-delete-from-print-queue-command   "lprm"
     texinfo-tex-trailer                       "@bye"
     tex-start-of-header                       "%**start"
     tex-end-of-header                         "%**end"
     tex-dvi-print-command                     "lpr -d"
     tex-show-queue-command                    "lpq"

You can change the values of these variables with the M-x edit-options command (see Editing Variable Values (The GNU Emacs Manual)), with the M-x set-variable command (see Examining and Setting Variables (The GNU Emacs Manual)), or with your .emacs initialization file (see Init File (The GNU Emacs Manual)).

Using the Local Variables List
==============================

Yet another way to apply the TeX formatting command to a Texinfo file is to put that command in a local variables list at the end of the Texinfo file.  You can then specify the tex or texi2dvi commands as a compile-command and have Emacs run it by typing M-x compile.  This creates a special shell called the *compilation* buffer in which Emacs runs the compile command. For example, at the end of the gdb.texinfo file, after the @bye, you could put the following:

     Local Variables:
     compile-command: "texi2dvi gdb.texinfo"
     End:

This technique is most often used by programmers who also compile programs this way; see Compilation (The GNU Emacs Manual).

TeX Formatting Requirements Summary
===================================

Every Texinfo file that is to be input to TeX must begin with a \input command and must contain an @setfilename command:

     \input texinfo
     @setfilename ARG-NOT-USED-BY-TEX

The first command instructs TeX to load the macros it needs to process a Texinfo file and the second command opens auxiliary files.

Every Texinfo file must end with a line that terminates TeX's processing and forces out unfinished pages:

     @bye

Strictly speaking, these lines are all a Texinfo file needs to be processed successfully by TeX.

Usually, however, the beginning includes an @settitle command to define the title of the printed manual, an @setchapternewpage command, a title page, a copyright page, and permissions.  Besides an @bye, the end of a file usually includes indices and a table of contents.  (And of course most manuals contain a body of text as well.)

For more information, see

@settitle,

@setchapternewpage,

Page Headings,

Titlepage & Copyright Page,

Printing Indices & Menus, and

Contents.

Preparing to Use TeX
====================

TeX needs to know where to find the texinfo.tex file that you have told it to input with the \input texinfo command at the beginning of the first line.  The texinfo.tex file tells TeX how to handle @-commands; it is included in all standard GNU distributions.

Usually, the texinfo.tex file is put under the default directory that contains TeX macros (/usr/local/share/texmf/tex/texinfo/texinfo.tex by default) when GNU Emacs or other GNU software is installed.  In this case, TeX will find the file and you do not need to do anything special. Alternatively, you can put texinfo.tex in the current directory when you run TeX, and TeX will find it there.

Also, you should install epsf.tex in the same place as texinfo.tex, if it is not already installed from another distribution.  This file is needed to support the @image command (see Images).

Optionally, you may create an additional texinfo.cnf, and install it as well.  This file is read by TeX at the @setfilename command (see @setfilename).  You can put any commands you like there according to local site-wide conventions, and they will be read by TeX when processing any Texinfo document.  For example, if texinfo.cnf contains the a single line @afourpaper (see A4 Paper), then all Texinfo documents will be processed with that page size in effect.  If you have nothing to put in texinfo.cnf, you do not need to create it.

If neither of the above locations for these system files suffice for you, you can specify the directories explicitly.  For texinfo.tex, you can do this by writing the complete path for the file after the \input command.  Another way, that works for both texinfo.tex and texinfo.cnf (and any other file TeX might read), is to set the TEXINPUTS environment variable in your .cshrc or .profile file.

Which you use of .cshrc or .profile depends on whether you use a Bourne shell-compatible (sh, bash, ksh, ...) or C shell-compatible (csh, tcsh) command interpreter.  The latter read the .cshrc file for initialization information, and the former read .profile.

In a .cshrc file, you could use the following csh command sequence:

     setenv TEXINPUTS .:/home/me/mylib:/usr/lib/tex/macros

In a .profile file, you could use the following sh command sequence:

     TEXINPUTS=.:/home/me/mylib:/usr/lib/tex/macros
     export TEXINPUTS

This would cause TeX to look for \input file first in the current directory, indicated by the ., then in a hypothetical user's me/mylib directory, and finally in a system directory.

Overfull ``hboxes''
===================

TeX is sometimes unable to typeset a line without extending it into the right margin.  This can occur when TeX comes upon what it interprets as a long word that it cannot hyphenate, such as an electronic mail network address or a very long title.  When this happens, TeX prints an error message like this:

     Overfull \hbox (20.76302pt too wide)

(In TeX, lines are in ``horizontal boxes'', hence the term, ``hbox''. The backslash, \, is the TeX equivalent of @.)

TeX also provides the line number in the Texinfo source file and the text of the offending line, which is marked at all the places that TeX knows how to hyphenate words. See Catching Errors with TeX Formatting, for more information about typesetting errors.

If the Texinfo file has an overfull hbox, you can rewrite the sentence so the overfull hbox does not occur, or you can decide to leave it.  A small excursion into the right margin often does not matter and may not even be noticeable.

However, unless told otherwise, TeX will print a large, ugly, black rectangle beside the line that contains the overfull hbox.  This is so you will notice the location of the problem if you are correcting a draft.

To prevent such a monstrosity from marring your final printout, write the following in the beginning of the Texinfo file on a line of its own, before the @titlepage command:

     @finalout

Printing ``Small'' Books
========================

By default, TeX typesets pages for printing in an 8.5 by 11 inch format.  However, you can direct TeX to typeset a document in a 7 by 9.25 inch format that is suitable for bound books by inserting the following command on a line by itself at the beginning of the Texinfo file, before the title page:

     @smallbook

(Since regular sized books are often about 7 by 9.25 inches, this command might better have been called the @regularbooksize command, but it came to be called the @smallbook command by comparison to the 8.5 by 11 inch format.)

If you write the @smallbook command between the start-of-header and end-of-header lines, the Texinfo mode TeX region formatting command, texinfo-tex-region, will format the region in ``small'' book size (see Start of Header).

The Free Software Foundation distributes printed copies of The GNU Emacs Manual and other manuals in the ``small'' book size. See @smallexample and @smalllisp, for information about commands that make it easier to produce examples for a smaller manual.

Alternatively, to avoid embedding this physical paper size in your document, use texi2dvi to format your document (see Format with texi2dvi), and supply -t @smallbook as an argument.  Then other people do not have to change the document source file to format it differently.

Printing on A4 Paper
====================

You can tell TeX to typeset a document for printing on European size A4 paper with the @afourpaper command.  Write the command on a line by itself between @iftex and @end iftex lines near the beginning of the Texinfo file, before the title page:

For example, this is how you would write the header for this manual:

     \input texinfo    @c -*-texinfo-*-
     @c %**start of header
     @setfilename texinfo
     @settitle Texinfo
     @syncodeindex vr fn
     @iftex
     @afourpaper
     @end iftex
     @c %**end of header

Alternatively, to avoid embedding this physical paper size in your document, use texi2dvi to format your document (see Format with texi2dvi), and supply -t @afourpaper as an argument.  Then other people do not have to change the document source file to format it differently.

Another alternative: put the @afourpaper command in the file texinfo.cnf that TeX will read.  (No need for @iftex there.)  This will automatically typeset all the Texinfo documents at your site with that paper size in effect.

Cropmarks and Magnification
===========================

You can attempt to direct TeX to print cropmarks at the corners of pages with the @cropmarks command.  Write the @cropmarks command on a line by itself between @iftex and @end iftex lines near the beginning of the Texinfo file, before the title page, like this:

     @iftex
     @cropmarks
     @end iftex

This command is mainly for printers that typeset several pages on one sheet of film; but you can attempt to use it to mark the corners of a book set to 7 by 9.25 inches with the @smallbook command. (Printers will not produce cropmarks for regular sized output that is printed on regular sized paper.)  Since different printing machines work in different ways, you should explore the use of this command with a spirit of adventure.  You may have to redefine the command in the texinfo.tex definitions file.

You can attempt to direct TeX to typeset pages larger or smaller than usual with the \mag TeX command.  Everything that is typeset is scaled proportionally larger or smaller.  (\mag stands for ``magnification''.)  This is not a Texinfo @-command, but is a plain TeX command that is prefixed with a backslash.  You have to write this command between @tex and @end tex (see Raw Formatter Commands).

Follow the \mag command with an = and then a number that is 1000 times the magnification you desire.  For example, to print pages at 1.2 normal size, write the following near the beginning of the Texinfo file, before the title page:

     @tex
     \mag=1200
     @end tex

With some printing technologies, you can print normal-sized copies that look better than usual by using a larger-than-normal master.

Depending on your system, \mag may not work or may work only at certain magnifications.  Be prepared to experiment.

Creating an Info File
*********************

makeinfo is a utility that converts a Texinfo file into an Info file; texinfo-format-region and texinfo-format-buffer are GNU Emacs functions that do the same.

A Texinfo file must contain an @setfilename line near its beginning, otherwise the Info formatting commands will fail.

For information on installing the Info file in the Info system, see Install an Info File.

makeinfo Preferred
==================

The makeinfo utility creates an Info file from a Texinfo source file more quickly than either of the Emacs formatting commands and provides better error messages.  We recommend it.  makeinfo is a C program that is independent of Emacs.  You do not need to run Emacs to use makeinfo, which means you can use makeinfo on machines that are too small to run Emacs. You can run makeinfo in any one of three ways: from an operating system shell, from a shell inside Emacs, or by typing a key command in Texinfo mode in Emacs.

The texinfo-format-region and the texinfo-format-buffer commands are useful if you cannot run makeinfo.  Also, in some circumstances, they format short regions or buffers more quickly than makeinfo.

Running makeinfo from a Shell
=============================

To create an Info file from a Texinfo file, type makeinfo followed by the name of the Texinfo file.  Thus, to create the Info file for Bison, type the following to the shell: is the prompt):

     makeinfo bison.texinfo

(You can run a shell inside Emacs by typing M-x shell.)

Sometimes you will want to specify options.  For example, if you wish to discover which version of makeinfo you are using, type:

     makeinfo --version

See makeinfo options, for more information.

Options for makeinfo
====================

The makeinfo command takes a number of options.  Most often, options are used to set the value of the fill column and specify the footnote style.  Each command line option is a word preceded by -- or a letter preceded by -.  You can use abbreviations for the long option names as long as they are unique.

For example, you could use the following shell command to create an Info file for bison.texinfo in which each line is filled to only 68 columns:

     makeinfo --fill-column=68 bison.texinfo

You can write two or more options in sequence, like this:

     makeinfo --no-split --fill-column=70 ...

This would keep the Info file together as one possibly very long file and would also set the fill column to 70.

The options are:

-D VAR
     Cause the variable VAR to be defined.  This is equivalent to @set VAR in the Texinfo file (see set clear value).

--error-limit=LIMIT
     Set the maximum number of errors that makeinfo will report before exiting (on the assumption that continuing would be useless); default 100.

--fill-column=WIDTH
     Specify the maximum number of columns in a line; this is the right-hand edge of a line.  Paragraphs that are filled will be filled to this width.  (Filling is the process of breaking up and connecting lines so that lines are the same length as or shorter than the number specified as the fill column.  Lines are broken between words.) The default value is 72.

--footnote-style=STYLE
     Set the footnote style to STYLE, either end for the end node style (the default) or separate for the separate node style. The value set by this option overrides the value set in a Texinfo file by an @footnotestyle command (see Footnotes).  When the footnote style is separate, makeinfo makes a new node containing the footnotes found in the current node.  When the footnote style is end, makeinfo places the footnote references at the end of the current node.

--force
     Ordinarily, if the input file has errors, the output files are not created.  With this option, they are preserved.

--help
     Print a usage message listing all available options, then exit successfully.

-I DIR
     Add dir to the directory search list for finding files that are included using the @include command.  By default, makeinfo searches only the current directory.

--no-headers
     Do not include menus or node lines in the output.  This results in an ASCII file that you cannot read in Info since it does not contain the requisite nodes or menus. It is primarily useful to extract certain pieces of a manual into separate files to be included in a distribution, such as INSTALL files.

--no-split
     Suppress the splitting stage of makeinfo.  By default, large output files (where the size is greater than 70k bytes) are split into smaller subfiles, each one approximately 50k bytes.

--no-pointer-validate
--no-validate
     Suppress the pointer-validation phase of makeinfo.  Normally, after a Texinfo file is processed, some consistency checks are made to ensure that cross references can be resolved, etc. See Pointer Validation.

--no-warn
     Suppress warning messages (but not error messages).  You might want this if the file you are creating has examples of Texinfo cross references within it, and the nodes that are referenced do not actually exist.

--no-number-footnotes
     Suppress automatic footnote numbering.  By default, makeinfo numbers each footnote sequentially in a single node, resetting the current footnote number to 1 at the start of each node.

--output=FILE
-o FILE
     Specify that the output should be directed to FILE and not to the file name specified in the @setfilename command found in the Texinfo source (see setfilename).  If FILE is -, output goes to standard output and --no-split is implied.

-P DIR
     Prepend dir to the directory search list for @include. See -I for more details.

--paragraph-indent=INDENT
     Set the paragraph indentation style to INDENT.  The value set by this option overrides the value set in a Texinfo file by an @paragraphindent command (see paragraphindent).  The value of INDENT is interpreted as follows:

     asis
          Preserve any existing indentation at the starts of paragraphs.

     0 or none
          Delete any existing indentation.

     NUM
          Indent each paragraph by that number of spaces.

--reference-limit=LIMIT
     Set the value of the number of references to a node that makeinfo will make without reporting a warning.  If a node has more than this number of references in it, makeinfo will make the references but also report a warning.  The default is 1000.

-U VAR
     Cause VAR to be undefined.  This is equivalent to @clear VAR in the Texinfo file (see set clear value).

--verbose
     Cause makeinfo to display messages saying what it is doing. Normally, makeinfo only outputs messages if there are errors or warnings.

--version
     Print the version number, then exit successfully.

Pointer Validation
==================

If you do not suppress pointer-validation, makeinfo will check the validity of the final Info file.  Mostly, this means ensuring that nodes you have referenced really exist.  Here is a complete list of what is checked:

 1. If a `Next', `Previous', or `Up' node reference is a reference to a node in the current file and is not an external reference such as to (dir), then the referenced node must exist.

 2. In every node, if the `Previous' node is different from the `Up' node, then the `Previous' node must also be pointed to by a `Next' node.

 3. Every node except the `Top' node must have an `Up' pointer.

 4. The node referenced by an `Up' pointer must contain a reference to the current node in some manner other than through a `Next' reference. This includes menu entries and cross references.

 5. If the `Next' reference of a node is not the same as the `Next' reference of the `Up' reference, then the node referenced by the `Next' pointer must have a `Previous' pointer that points back to the current node. This rule allows the last node in a section to point to the first node of the next chapter.

Running makeinfo inside Emacs
=============================

You can run makeinfo in GNU Emacs Texinfo mode by using either the makeinfo-region or the makeinfo-buffer commands.  In Texinfo mode, the commands are bound to C-c C-m C-r and C-c C-m C-b by default.

C-c C-m C-r
M-x makeinfo-region
     Format the current region for Info.

C-c C-m C-b
M-x makeinfo-buffer
     Format the current buffer for Info.

When you invoke either makeinfo-region or makeinfo-buffer, Emacs prompts for a file name, offering the name of the visited file as the default.  You can edit the default file name in the minibuffer if you wish, before pressing RET to start the makeinfo process.

The Emacs makeinfo-region and makeinfo-buffer commands run the makeinfo program in a temporary shell buffer.  If makeinfo finds any errors, Emacs displays the error messages in the temporary buffer.

You can parse the error messages by typing C-x ` (next-error).  This causes Emacs to go to and position the cursor on the line in the Texinfo source that makeinfo thinks caused the error.  See Running make or Compilers Generally (The GNU Emacs Manual), for more information about using the next-error command.

In addition, you can kill the shell in which the makeinfo command is running or make the shell buffer display its most recent output.

C-c C-m C-k
M-x makeinfo-kill-job
     Kill the current running makeinfo job created by makeinfo-region or makeinfo-buffer.

C-c C-m C-l
M-x makeinfo-recenter-output-buffer
     Redisplay the makeinfo shell buffer to display its most recent output.

(Note that the parallel commands for killing and recentering a TeX job are C-c C-t C-k and C-c C-t C-l.  See Texinfo Mode Printing.)

You can specify options for makeinfo by setting the makeinfo-options variable with either the M-x edit-options or the M-x set-variable command, or by setting the variable in your .emacs initialization file.

For example, you could write the following in your .emacs file:

     (setq makeinfo-options
           "--paragraph-indent=0 --no-split
            --fill-column=70 --verbose")

For more information, see

Editing Variable Values (The GNU Emacs Manual),

Examining and Setting Variables (The GNU Emacs Manual),

Init File (The GNU Emacs Manual), and

Options for makeinfo.

The texinfo-format... Commands
==============================

In GNU Emacs in Texinfo mode, you can format part or all of a Texinfo file with the texinfo-format-region command.  This formats the current region and displays the formatted text in a temporary buffer called *Info Region*.

Similarly, you can format a buffer with the texinfo-format-buffer command.  This command creates a new buffer and generates the Info file in it.  Typing C-x C-s will save the Info file under the name specified by the @setfilename line which must be near the beginning of the Texinfo file.

C-c C-e C-r
texinfo-format-region
     Format the current region for Info.

C-c C-e C-b
texinfo-format-buffer
     Format the current buffer for Info.

The texinfo-format-region and texinfo-format-buffer commands provide you with some error checking, and other functions can provide you with further help in finding formatting errors.  These procedures are described in an appendix; see Catching Mistakes. However, the makeinfo program is often faster and provides better error checking (see makeinfo in Emacs).

Batch Formatting
================

You can format Texinfo files for Info using batch-texinfo-format and Emacs Batch mode.  You can run Emacs in Batch mode from any shell, including a shell inside of Emacs.  (see Command Line Switches and Arguments (The GNU Emacs Manual).)

Here is a shell command to format all the files that end in .texinfo in the current directory:

     emacs -batch -funcall batch-texinfo-format *.texinfo

Emacs processes all the files listed on the command line, even if an error occurs while attempting to format some of them.

Run batch-texinfo-format only with Emacs in Batch mode as shown; it is not interactive.  It kills the Batch mode Emacs on completion.

batch-texinfo-format is convenient if you lack makeinfo and want to format several Texinfo files at once.  When you use Batch mode, you create a new Emacs process.  This frees your current Emacs, so you can continue working in it.  (When you run texinfo-format-region or texinfo-format-buffer, you cannot use that Emacs for anything else until the command finishes.)

Tag Files and Split Files
=========================

If a Texinfo file has more than 30,000 bytes, texinfo-format-buffer automatically creates a tag table for its Info file;  makeinfo always creates a tag table.  With a tag table, Info can jump to new nodes more quickly than it can otherwise.

In addition, if the Texinfo file contains more than about 70,000 bytes, texinfo-format-buffer and makeinfo split the large Info file into shorter indirect subfiles of about 50,000 bytes each.  Big files are split into smaller files so that Emacs does not need to make a large buffer to hold the whole of a large Info file; instead, Emacs allocates just enough memory for the small, split off file that is needed at the time.  This way, Emacs avoids wasting memory when you run Info.  (Before splitting was implemented, Info files were always kept short and include files were designed as a way to create a single, large printed manual out of the smaller Info files.  See Include Files, for more information.  Include files are still used for very large documents, such as The Emacs Lisp Reference Manual, in which each chapter is a separate file.)

When a file is split, Info itself makes use of a shortened version of the original file that contains just the tag table and references to the files that were split off.  The split off files are called indirect files.

The split off files have names that are created by appending -1, -2, -3 and so on to the file name specified by the @setfilename command.  The shortened version of the original file continues to have the name specified by @setfilename.

At one stage in writing this document, for example, the Info file was saved as test-texinfo and that file looked like this:

     Info file: test-texinfo,    -*-Text-*-
     produced by texinfo-format-buffer
     from file: new-texinfo-manual.texinfo

     ^_
     Indirect:
     test-texinfo-1: 102
     test-texinfo-2: 50422

     test-texinfo-3: 101300
     ^_^L
     Tag table:
     (Indirect)
     Node: overview^?104
     Node: info file^?1271

     Node: printed manual^?4853
     Node: conventions^?6855
     ...

(But test-texinfo had far more nodes than are shown here.)  Each of the split off, indirect files, test-texinfo-1, test-texinfo-2, and test-texinfo-3, is listed in this file after the line that says Indirect:.  The tag table is listed after the line that says Tag table:.

In the list of indirect files, the number following the file name records the cumulative number of bytes in the preceding indirect files, not counting the file list itself, the tag table, or the permissions text in each file.  In the tag table, the number following the node name records the location of the beginning of the node, in bytes from the beginning.

If you are using texinfo-format-buffer to create Info files, you may want to run the Info-validate command.  (The makeinfo command does such a good job on its own, you do not need Info-validate.)  However, you cannot run the M-x Info-validate node-checking command on indirect files.  For information on how to prevent files from being split and how to validate the structure of the nodes, see Using Info-validate.

Installing an Info File
***********************

Info files are usually kept in the info directory.  You can read Info files using the standalone Info program or the Info reader built into Emacs.  (see info, for an introduction to Info.)

The dir File
============

For Info to work, the info directory must contain a file that serves as a top level directory for the Info system.  By convention, this file is called dir.  (You can find the location of this file within Emacs by typing C-h i to enter Info and then typing C-x C-f to see the pathname to the info directory.)

The dir file is itself an Info file.  It contains the top level menu for all the Info files in the system.  The menu looks like this:

     * Menu:

     * Info:    (info).     Documentation browsing system.
     * Emacs:   (emacs).    The extensible, self-documenting
                            text editor.
     * Texinfo: (texinfo).  With one source file, make
                            either a printed manual using
                            TeX or an Info file.
     ...

Each of these menu entries points to the `Top' node of the Info file that is named in parentheses.  (The menu entry does not need to specify the `Top' node, since Info goes to the `Top' node if no node name is mentioned.  See Nodes in Other Info Files.)

Thus, the Info entry points to the `Top' node of the info file and the Emacs entry points to the `Top' node of the emacs file.

In each of the Info files, the `Up' pointer of the `Top' node refers back to the dir file.  For example, the line for the `Top' node of the Emacs manual looks like this in Info:

     File: emacs  Node: Top, Up: (DIR), Next: Distrib

(Note that in this case, the dir file name is written in upper case letters---it can be written in either upper or lower case.  Info has a feature that it will change the case of the file name to lower case if it cannot find the name as written.)

Listing a New Info File
=======================

To add a new Info file to your system, you must write a menu entry to add to the menu in the dir file in the info directory. For example, if you were adding documentation for GDB, you would write the following new entry:

     * GDB: (gdb).           The source-level C debugger.

The first part of the menu entry is the menu entry name, followed by a colon.  The second part is the name of the Info file, in parentheses, followed by a period.  The third part is the description.

The name of an Info file often has a .info extension.  Thus, the Info file for GDB might be called either gdb or gdb.info. The Info reader programs automatically try the file name both with and without .info; so it is better to avoid clutter and not to write .info explicitly in the menu entry.  For example, the GDB menu entry should use just gdb for the file name, not gdb.info.

Info Files in Other Directories
===============================

If an Info file is not in the info directory, there are three ways to specify its location:

  * Write the pathname in the dir file as the second part of the menu.

  * If you are using Emacs, list the name of the file in a second dir file, in its directory; and then add the name of that directory to the Info-directory-list variable in your personal or site initialization file.

     This tells Emacs where to look for dir files.  Emacs merges the files named dir from each of the listed directories.  (In Emacs version 18, you can set the Info-directory variable to the name of only one directory.)

  * Specify the Info directory name in the INFOPATH environment variable in your .profile or .cshrc initialization file. (Only you and others who set this environment variable will be able to find Info files whose location is specified this way.)

For example, to reach a test file in the /home/bob/manuals directory, you could add an entry like this to the menu in the dir file:

     * Test: (/home/bob/manuals/info-test).  Bob's own test file.

In this case, the absolute file name of the info-test file is written as the second part of the menu entry.

Alternatively, you could write the following in your .emacs file:

     (setq Info-directory-list
           '("/home/bob/manuals"
             "/usr/local/info"))

This tells Emacs to merge the dir file from the /home/bob/manuals directory with the dir file from the /usr/local/info directory.  Info will list the /home/bob/manuals/info-test file as a menu entry in the /home/bob/manuals/dir file.

Finally, you can tell Info where to look by setting the INFOPATH environment variable in your .cshrc or .profile file.  If you use a Bourne-compatible shell such as sh or bash for your shell command interpreter, you set the INFOPATH environment variable in the .profile initialization file; but if you use csh or tcsh, you must set the variable in the .cshrc initialization file.  The two types of shells use different syntax.

  * In a .cshrc file, you could set the INFOPATH variable as follows:

          setenv INFOPATH .:~/manuals:/usr/local/emacs/info

  * In a .profile file, you would achieve the same effect by writing:

          INFOPATH=.:$HOME/manuals:/usr/local/emacs/info
          export INFOPATH

The . indicates the current directory as usual.  Emacs uses the INFOPATH environment variable to initialize the value of Emacs's own Info-directory-list variable.

However you set INFOPATH, if its last character is a colon, this is replaced by the default (compiled-in) path.  This gives you a way to augment the default path with new directories without having to list all the standard places.  For example (using sh syntax:

     INFOPATH=/local/info:
     export INFOPATH

will search /local/info first, then the standard directories. Leading or doubled colons are not treated specially.

Installing Info Directory Files
===============================

When you install an Info file onto your system, you can use the program install-info to update the Info directory file dir. Normally the makefile for the package runs install-info, just after copying the Info file into its proper installed location.

In order for the Info file to work with install-info, you should use the commands @dircategory and @direntry in the Texinfo source file.  Use @direntry to specify the menu entry to add to the Info directory file, and use @dircategory to specify which part of the Info directory to put it in.  Here is how these commands are used in this manual:

     @dircategory Texinfo documentation system
     @direntry
     * Texinfo: (texinfo).           The GNU documentation format.
     * install-info: (texinfo)Invoking install-info. ...
     ...
     @end direntry

Here's what this produces in the Info file:

     INFO-DIR-SECTION Texinfo documentation system
     START-INFO-DIR-ENTRY
     * Texinfo: (texinfo).           The GNU documentation format.
     * install-info: (texinfo)Invoking install-info. ...
     ...
     END-INFO-DIR-ENTRY

The install-info program sees these lines in the Info file, and that is how it knows what to do.

Always use the @direntry and @dircategory commands near the beginning of the Texinfo input, before the first @node command.  If you use them later on in the input, install-info will not notice them.

If you use @dircategory more than once in the Texinfo source, each usage specifies one category; the new menu entry is added to the Info directory file in each of the categories you specify.  If you use @direntry more than once, each usage specifies one menu entry; each of these menu entries is added to the directory in each of the specified categories.

Invoking install-info
=====================

install-info inserts menu entries from an Info file into the top-level dir file in the Info system (see the previous sections for an explanation of how the dir file works).  It's most often run as part of software installation, or when constructing a dir file for all manuals on a system.  Synopsis:

     install-info [OPTION]... [INFO-FILE [DIR-FILE]]

If INFO-FILE or DIR-FILE are not specified, the various options (described below) that define them must be.  There are no compile-time defaults, and standard input is never used. install-info can read only one info file and write only one dir file per invocation.

If DIR-FILE (however specified) does not exist, install-info creates it if possible (with no entries).

Options:

--delete
     Delete the entries in INFO-FILE from DIR-FILE.  The file name in the entry in DIR-FILE must be INFO-FILE (except for an optional .info in either one).  Don't insert any new entries.

--dir-file=NAME
     Specify file name of the Info directory file.  This is equivalent to using the DIR-FILE argument.

--entry=TEXT
     Insert TEXT as an Info directory entry; TEXT should have the form of an Info menu item line plus zero or more extra lines starting with whitespace.  If you specify more than one entry, they are all added.  If you don't specify any entries, they are determined from information in the Info file itself.

--help
     Display a usage message listing basic usage and all available options, then exit successfully.

--info-file=FILE
     Specify Info file to install in the directory. This is equivalent to using the INFO-FILE argument.

--info-dir=DIR
     Equivalent to --dir-file=DIR/dir.

--item=TEXT
     Same as --entry=TEXT.  An Info directory entry is actually a menu item.

--quiet
     Suppress warnings.

--remove
     Same as --delete.

--section=SEC
     Put this file's entries in section SEC of the directory.  If you specify more than one section, all the entries are added in each of the sections.  If you don't specify any sections, they are determined from information in the Info file itself.

--version
     Display version information and exit successfully.

@-Command List
**************

Here is an alphabetical list of the @-commands in Texinfo.  Square brackets, [ ], indicate optional arguments; an ellipsis, ..., indicates repeated text.

@WHITESPACE
     An @ followed by a space, tab, or newline produces a normal, stretchable, interword space.  See Multiple Spaces.

@!
     Generate an exclamation point that really does end a sentence (usually after an end-of-sentence capital letter).  See Ending a Sentence.

@"
@'
     Generate an umlaut or acute accent, respectively, over the next character, as in ö and ó.  See Inserting Accents.

@*
     Force a line break. Do not end a paragraph that uses @* with an @refill command.  See Line Breaks.

@,{C}
     Generate a cedilla accent under C, as in ç.  See Inserting Accents.

@-
     Insert a discretionary hyphenation point.  See - and hyphenation.

@.
     Produce a period that really does end a sentence (usually after an end-of-sentence capital letter).  See Ending a Sentence.

@:
     Indicate to TeX that an immediately preceding period, question mark, exclamation mark, or colon does not end a sentence.  Prevent TeX from inserting extra whitespace as it does at the end of a sentence.  The command has no effect on the Info file output. See Not Ending a Sentence.

@=
     Generate a macro (bar) accent over the next character, as in ō. See Inserting Accents.

@?
     Generate a question mark that really does end a sentence (usually after an end-of-sentence capital letter).  See Ending a Sentence.

@@
     Stands for an at sign, @. See Inserting @ and braces.

@^
@`
     Generate a circumflex (hat) or grave accent, respectively, over the next character, as in ô. See Inserting Accents.

@{
     Stands for a left brace, {. See Inserting @ and braces.

@}
     Stands for a right-hand brace, }.

     See Inserting @ and braces.

@=
     Generate a tilde accent over the next character, as in Ñ. See Inserting Accents.

@AA{}
@aa{}
     Generate the uppercase and lowercase Scandinavian A-ring letters, respectively: Å, å.  See Inserting Accents.

@AE{}
@ae{}
     Generate the uppercase and lowercase AE ligatures, respectively: Æ, æ.  See Inserting Accents.

@afourpaper
     Change page dimensions for the A4 paper size. Only allowed inside @iftex ... @end iftex. See A4 Paper.

@appendix TITLE
     Begin an appendix.  The title appears in the table of contents of a printed manual.  In Info, the title is underlined with asterisks.  See The @unnumbered and @appendix Commands.

@appendixsec TITLE
@appendixsection TITLE
     Begin an appendix section within an appendix.  The section title appears in the table of contents of a printed manual.  In Info, the title is underlined with equal signs.  @appendixsection is a longer spelling of the @appendixsec command.  See Section Commands.

@appendixsubsec TITLE
     Begin an appendix subsection within an appendix.  The title appears in the table of contents of a printed manual.  In Info, the title is underlined with hyphens.  See Subsection Commands.

@appendixsubsubsec TITLE
     Begin an appendix subsubsection within an appendix subsection.  The title appears in the table of contents of a printed manual.  In Info, the title is underlined with periods.  See The `subsub' Commands.

@asis
     Used following @table, @ftable, and @vtable to print the table's first column without highlighting (``as is''). See Making a Two-column Table.

@author AUTHOR
     Typeset AUTHOR flushleft and underline it.  See The @title and @author Commands.

@b{TEXT}
     Print TEXT in bold font.  No effect in Info.  See Fonts.

@bullet{}
     Generate a large round dot, or the closest possible thing to one.  See @bullet.

@bye
     Stop formatting a file.  The formatters do not see the contents of a file following an @bye command.  See Ending a File.

@c COMMENT
     Begin a comment in Texinfo.  The rest of the line does not appear in either the Info file or the printed manual.  A synonym for @comment.  See Comments.

@cartouche
     Highlight an example or quotation by drawing a box with rounded corners around it.  Pair with @end cartouche.  No effect in Info.  See Drawing Cartouches Around Examples.)

@center LINE-OF-TEXT
     Center the line of text following the command. See @center.

@centerchap LINE-OF-TEXT
     Like @chapter, but centers the chapter title.  See @chapter.

@chapheading TITLE
     Print a chapter-like heading in the text, but not in the table of contents of a printed manual.  In Info, the title is underlined with asterisks.  See @majorheading and @chapheading.

@chapter TITLE
     Begin a chapter.  The chapter title appears in the table of contents of a printed manual.  In Info, the title is underlined with asterisks.  See @chapter.

@cindex ENTRY
     Add ENTRY to the index of concepts.  See Defining the Entries of an Index.

@cite{REFERENCE}
     Highlight the name of a book or other reference that lacks a companion Info file.  See @cite.

@clear FLAG
     Unset FLAG, preventing the Texinfo formatting commands from formatting text between subsequent pairs of @ifset FLAG and @end ifset commands, and preventing @value{FLAG} from expanding to the value to which FLAG is set. See @set @clear @value.

@code{SAMPLE-CODE}
     Highlight text that is an expression, a syntactically complete token of a program, or a program name.  See @code.

@comment COMMENT
     Begin a comment in Texinfo.  The rest of the line does not appear in either the Info file or the printed manual.  A synonym for @c. See Comments.

@contents
     Print a complete table of contents.  Has no effect in Info, which uses menus instead.  See Generating a Table of Contents.

@copyright{}
     Generate a copyright symbol.  See @copyright.

@defcodeindex INDEX-NAME
     Define a new index and its indexing command.  Print entries in an @code font.  See Defining New Indices.

@defcv CATEGORY CLASS NAME
@defcvx CATEGORY CLASS NAME
     Format a description for a variable associated with a class in object-oriented programming.  Takes three arguments: the category of thing being defined, the class to which it belongs, and its name. See Definition Commands, and Def Cmds in Detail.

@deffn CATEGORY NAME ARGUMENTS...
@deffnx CATEGORY NAME ARGUMENTS...
     Format a description for a function, interactive command, or similar entity that may take arguments.  @deffn takes as arguments the category of entity being described, the name of this particular entity, and its arguments, if any.  See Definition Commands.

@defindex INDEX-NAME
     Define a new index and its indexing command.  Print entries in a roman font.  See Defining New Indices.

@definfoenclose NEW-COMMAND, BEFORE, AFTER,
     Create new @-command for Info that marks text by enclosing it in strings that precede and follow the text.  Write definition inside of @ifinfo ... @end ifinfo. See Customized Highlighting.

@defivar CLASS INSTANCE-VARIABLE-NAME
@defivarx CLASS INSTANCE-VARIABLE-NAME
     This command formats a description for an instance variable in object-oriented programming.  The command is equivalent to @defcv {Instance Variable} ....  See Definition Commands, and Def Cmds in Detail.

@defmac MACRO-NAME ARGUMENTS...
@defmacx MACRO-NAME ARGUMENTS...
     Format a description for a macro.  The command is equivalent to @deffn Macro ....  See Definition Commands, and Def Cmds in Detail.

@defmethod CLASS METHOD-NAME ARGUMENTS...
@defmethodx CLASS METHOD-NAME ARGUMENTS...
     Format a description for a method in object-oriented programming.  The command is equivalent to @defop Method ....  Takes as arguments the name of the class of the method, the name of the method, and its arguments, if any.  See Definition Commands, and Def Cmds in Detail.

@defop CATEGORY CLASS NAME ARGUMENTS...
@defopx CATEGORY CLASS NAME ARGUMENTS...
     Format a description for an operation in object-oriented programming. @defop takes as arguments the overall name of the category of operation, the name of the class of the operation, the name of the operation, and its arguments, if any.  See Definition Commands, and Def Cmds in Detail.

@defopt OPTION-NAME
@defoptx OPTION-NAME
     Format a description for a user option.  The command is equivalent to @defvr {User Option} ....  See Definition Commands, and Def Cmds in Detail.

@defspec SPECIAL-FORM-NAME ARGUMENTS...
@defspecx SPECIAL-FORM-NAME ARGUMENTS...
     Format a description for a special form.  The command is equivalent to @deffn {Special Form} ....  See Definition Commands, and Def Cmds in Detail.

@deftp CATEGORY NAME-OF-TYPE ATTRIBUTES...
@deftpx CATEGORY NAME-OF-TYPE ATTRIBUTES...
     Format a description for a data type.  @deftp takes as arguments the category, the name of the type (which is a word like int or float), and then the names of attributes of objects of that type. See Definition Commands, and Def Cmds in Detail.

@deftypefn CLASSIFICATION DATA-TYPE NAME ARGUMENTS...
@deftypefnx CLASSIFICATION DATA-TYPE NAME ARGUMENTS...
     Format a description for a function or similar entity that may take arguments and that is typed.  @deftypefn takes as arguments the classification of entity being described, the type, the name of the entity, and its arguments, if any.  See Definition Commands, and Def Cmds in Detail.

@deftypefun DATA-TYPE FUNCTION-NAME ARGUMENTS...
@deftypefunx DATA-TYPE FUNCTION-NAME ARGUMENTS...
     Format a description for a function in a typed language. The command is equivalent to @deftypefn Function .... See Definition Commands, and Def Cmds in Detail.

@deftypemethod CLASS DATA-TYPE METHOD-NAME ARGUMENTS...
@deftypemethodx CLASS DATA-TYPE METHOD-NAME ARGUMENTS...
     Format a description for a typed method in object-oriented programming. Takes as arguments the name of the class of the method, the return type of the method, the name of the method, and its arguments, if any. See Definition Commands, and Def Cmds in Detail.

@deftypevr CLASSIFICATION DATA-TYPE NAME
@deftypevrx CLASSIFICATION DATA-TYPE NAME
     Format a description for something like a variable in a typed language---an entity that records a value.  Takes as arguments the classification of entity being described, the type, and the name of the entity.  See Definition Commands, and Def Cmds in Detail.

@deftypevar DATA-TYPE VARIABLE-NAME
@deftypevarx DATA-TYPE VARIABLE-NAME
     Format a description for a variable in a typed language.  The command is equivalent to @deftypevr Variable ....  See Definition Commands, and Def Cmds in Detail.

@defun FUNCTION-NAME ARGUMENTS...
@defunx FUNCTION-NAME ARGUMENTS...
     Format a description for functions.  The command is equivalent to @deffn Function ....  See Definition Commands, and Def Cmds in Detail.

@defvar VARIABLE-NAME
@defvarx VARIABLE-NAME
     Format a description for variables.  The command is equivalent to @defvr Variable ....  See Definition Commands, and Def Cmds in Detail.

@defvr CATEGORY NAME
@defvrx CATEGORY NAME
     Format a description for any kind of variable.  @defvr takes as arguments the category of the entity and the name of the entity. See Definition Commands, and Def Cmds in Detail.

@detailmenu{}
     Avoid makeinfo confusion stemming from the detailed node listing in a master menu.  See Master Menu Parts.

@dfn{TERM}
     Highlight the introductory or defining use of a term. See @dfn.

@dircategory DIRPART
     Specify a part of the Info directory menu where this file's entry should go.  See Installing Dir Entries.

@direntry
     Begin the Info directory menu entry for this file. See Installing Dir Entries.

@display
     Begin a kind of example.  Indent text, do not fill, do not select a new font.  Pair with @end display.  See @display.

@dmn{DIMENSION}
     Format a unit of measure, as in 12pt.  Causes TeX to insert a thin space before DIMENSION.  No effect in Info. See @dmn.

@dotaccent{C}
     Generate a dot accent over the character C, as in ȯo. See Inserting Accents.

@dots{}
     Insert an ellipsis: .... See @dots.

@email{ADDRESS}
     Indicate an electronic mail address. See @email.

@emph{TEXT}
     Highlight TEXT; text is displayed in italics in printed output, and surrounded by asterisks in Info.  See Emphasizing Text.

@end ENVIRONMENT
     Ends ENVIRONMENT, as in @end example.  See @-commands.

@enddots{}
     Generate an end-of-sentence of ellipsis, like this ... See @dots{}.

@enumerate [NUMBER-OR-LETTER]
     Begin a numbered list, using @item for each entry. Optionally, start list with NUMBER-OR-LETTER.  Pair with @end enumerate.  See @enumerate.

@equiv{}
     Indicate to the reader the exact equivalence of two forms with a glyph: ==.  See Equivalence.

@error{}
     Indicate to the reader with a glyph that the following text is an error message: error-->.  See Error Glyph.

@evenfooting [LEFT] @| [CENTER] @| [RIGHT]
@evenheading [LEFT] @| [CENTER] @| [RIGHT]
     Specify page footings resp. headings for even-numbered (left-hand) pages.  Only allowed inside @iftex.  See How to Make Your Own Headings.

@everyfooting [LEFT] @| [CENTER] @| [RIGHT]
@everyheading [LEFT] @| [CENTER] @| [RIGHT]
     Specify page footings resp. headings for every page.  Not relevant to Info.  See How to Make Your Own Headings.

@example
     Begin an example.  Indent text, do not fill, and select fixed-width font. Pair with @end example.  See @example.

@exclamdown{}
     Produce an upside-down exclamation point.  See Inserting Accents.

@exdent LINE-OF-TEXT
     Remove any indentation a line might have.  See Undoing the Indentation of a Line.

@expansion{}
     Indicate the result of a macro expansion to the reader with a special glyph: ==>. See ==> Indicating an Expansion.

@file{FILENAME}
     Highlight the name of a file, buffer, node, or directory.  See @file.

@finalout
     Prevent TeX from printing large black warning rectangles beside over-wide lines.  See Overfull hboxes.

@findex ENTRY
     Add ENTRY to the index of functions.  See Defining the Entries of an Index.

@flushleft
@flushright
     Left justify every line but leave the right end ragged. Leave font as is.  Pair with @end flushleft. @flushright analogous. See @flushleft and @flushright.

@footnote{TEXT-OF-FOOTNOTE}
     Enter a footnote.  Footnote text is printed at the bottom of the page by TeX; Info may format in either `End' node or `Separate' node style. See Footnotes.

@footnotestyle STYLE
     Specify an Info file's footnote style, either end for the end node style or separate for the separate node style. See Footnotes.

@format
     Begin a kind of example.  Like @example or @display, but do not narrow the margins and do not select the fixed-width font. Pair with @end format.  See @example.

@ftable FORMATTING-COMMAND
     Begin a two-column table, using @item for each entry. Automatically enter each of the items in the first column into the index of functions.  Pair with @end ftable.  The same as @table, except for indexing.  See @ftable and @vtable.

@group
     Hold text together that must appear on one printed page.  Pair with @end group.  Not relevant to Info.  See @group.

@H{C}
     Generate the long Hungarian umlaut accent over C, as in ő.

@heading TITLE
     Print an unnumbered section-like heading in the text, but not in the table of contents of a printed manual.  In Info, the title is underlined with equal signs.  See Section Commands.

@headings ON-OFF-SINGLE-DOUBLE
     Turn page headings on or off, and/or specify single-sided or double-sided page headings for printing.  See The @headings Command.

@html
     Enter HTML completely.  Pair with @end html.  See Raw Formatter Commands.

@hyphenation{HY-PHEN-A-TED WORDS}
     Explicitly define hyphenation points.  See @- and @hyphenation.

@i{TEXT}
     Print TEXT in italic font.  No effect in Info. See Fonts.

@ifclear FLAG
     If FLAG is cleared, the Texinfo formatting commands format text between @ifclear FLAG and the following @end ifclear command. See @set @clear @value.

@ifhtml
@ifinfo
     Begin a stretch of text that will be ignored by TeX when it typesets the printed manual.  The text appears only in the HTML resp. Info file.  Pair with @end ifhtml resp. @end ifinfo. See Conditionals.

@ifnothtml
@ifnotinfo
@ifnottex
     Begin a stretch of text that will be ignored in one output format but not the others.  The text appears only in the format not specified. Pair with @end ifnothtml resp. @end ifnotinfo resp. @end ifnotinfo.  See Conditionals.

@ifset FLAG
     If FLAG is set, the Texinfo formatting commands format text between @ifset FLAG and the following @end ifset command. See @set @clear @value.

@iftex
     Begin a stretch of text that will not appear in the Info file, but will be processed only by TeX.  Pair with @end iftex. See Conditionally Visible Text.

@ignore
     Begin a stretch of text that will not appear in either the Info file or the printed output.  Pair with @end ignore. See Comments and Ignored Text.

@image{FILENAME, [WIDTH], [HEIGHT]}
     Include graphics image in external FILENAME scaled to the given WIDTH and/or HEIGHT.  See Images.

@include FILENAME
     Incorporate the contents of the file FILENAME into the Info file or printed document.  See Include Files.

@inforef{NODE-NAME, [ENTRY-NAME], INFO-FILE-NAME}
     Make a cross reference to an Info file for which there is no printed manual.  See Cross references using @inforef.

\input MACRO-DEFINITIONS-FILE
     Use the specified macro definitions file.  This command is used only in the first line of a Texinfo file to cause TeX to make use of the texinfo macro definitions file.  The backslash in \input is used instead of an @ because TeX does not recognize @ until after it has read the definitions file. See The Texinfo File Header.

@item
     Indicate the beginning of a marked paragraph for @itemize and @enumerate; indicate the beginning of the text of a first column entry for @table, @ftable, and @vtable. See Lists and Tables.

@itemize  MARK-GENERATING-CHARACTER-OR-COMMAND
     Produce a sequence of indented paragraphs, with a mark inside the left margin at the beginning of each paragraph.  Pair with @end itemize.  See @itemize.

@itemx
     Like @item but do not generate extra vertical space above the item text.  See @itemx.

@kbd{KEYBOARD-CHARACTERS}
     Indicate text that is characters of input to be typed by users.  See @kbd.

@kbdinputstyle STYLE
     Specify when @kbd should use a font distinct from @code. See @kbd.

@key{KEY-NAME}
     Indicate a name for a key on a keyboard. See @key.

@kindex ENTRY
     Add ENTRY to the index of keys. See Defining the Entries of an Index.

@L{}
@l{}
     Generate the uppercase and lowercase Polish suppressed-L letters, respectively: Ł, ł.

@lisp
     Begin an example of Lisp code.  Indent text, do not fill, and select fixed-width font.  Pair with @end lisp.  See @lisp.

@lowersections
     Change subsequent chapters to sections, sections to subsections, and so on. See @raisesections and @lowersections.

@macro MACRO-NAME {PARAMS}
     Define a new Texinfo command @MACRO-NAME{PARAMS}. Only supported by makeinfo and texi2dvi.  See Defining Macros.

@majorheading TITLE
     Print a chapter-like heading in the text, but not in the table of contents of a printed manual.  Generate more vertical whitespace before the heading than the @chapheading command.  In Info, the chapter heading line is underlined with asterisks.  See @majorheading and @chapheading.

@math{MATHEMATICAL-EXPRESSION}
     Format a mathematical expression. See @math: Inserting Mathematical Expressions.

@menu
     Mark the beginning of a menu of nodes in Info.  No effect in a printed manual.  Pair with @end menu.  See Menus.

@minus{}
     Generate a minus sign, `-'.  See @minus.

@multitable COLUMN-WIDTH-SPEC
     Begin a multi-column table.  Pair with @end multitable. See Multitable Column Widths.

@need N
     Start a new page in a printed manual if fewer than N mils (thousandths of an inch) remain on the current page.  See @need.

@node NAME, NEXT, PREVIOUS, UP
     Define the beginning of a new node in Info, and serve as a locator for references for TeX.  See @node.

@noindent
     Prevent text from being indented as if it were a new paragraph. See @noindent.

@O{}
@o{}
     Generate the uppercase and lowercase O-with-slash letters, respectively: Ø, ø.

@oddfooting [LEFT] @| [CENTER] @| [RIGHT]
@oddheading [LEFT] @| [CENTER] @| [RIGHT]
     Specify page footings resp. headings for odd-numbered (right-hand) pages.  Only allowed inside @iftex.  See How to Make Your Own Headings.

@OE{}
@oe{}
     Generate the uppercase and lowercase OE ligatures, respectively: Œ, œ.  See Inserting Accents.

@page
     Start a new page in a printed manual.  No effect in Info. See @page.

@paragraphindent INDENT
     Indent paragraphs by INDENT number of spaces; delete indentation if the value of INDENT is 0; and do not change indentation if INDENT is asis. See Paragraph Indenting.

@pindex ENTRY
     Add ENTRY to the index of programs.  See Defining the Entries of an Index.

@point{}
     Indicate the position of point in a buffer to the reader with a glyph: -!-.  See Indicating Point in a Buffer.

@pounds{}
     Generate the pounds sterling currency sign. See @pounds{}.

@print{}
     Indicate printed output to the reader with a glyph: -|.  See Print Glyph.

@printindex INDEX-NAME
     Print an alphabetized two-column index in a printed manual or generate an alphabetized menu of index entries for Info.  See Printing Indices & Menus.

@pxref{NODE-NAME, [ENTRY], [TOPIC-OR-TITLE], [INFO-FILE], [MANUAL]}
     Make a reference that starts with a lower case `see' in a printed manual.  Use within parentheses only.  Do not follow command with a punctuation mark---the Info formatting commands automatically insert terminating punctuation as needed.  Only the first argument is mandatory. See @pxref.

@questiondown{}
     Generate an upside-down question mark.  See Inserting Accents.

@quotation
     Narrow the margins to indicate text that is quoted from another real or imaginary work.  Write command on a line of its own.  Pair with @end quotation.  See @quotation.

@r{TEXT}
     Print TEXT in roman font.  No effect in Info. See Fonts.

@raisesections
     Change subsequent sections to chapters, subsections to sections, and so on.  See @raisesections and @lowersections.

@ref{NODE-NAME, [ENTRY], [TOPIC-OR-TITLE], [INFO-FILE], [MANUAL]}
     Make a reference.  In a printed manual, the reference does not start with a `See'.  Follow command with a punctuation mark.  Only the first argument is mandatory.  See @ref.

@refill
     In Info, refill and indent the paragraph after all the other processing has been done.  No effect on TeX, which always refills.  This command is no longer needed, since all formatters now automatically refill. See Refilling Paragraphs.

@result{}
     Indicate the result of an expression to the reader with a special glyph: =>.  See @result.

@ringaccent{C}
     Generate a ring accent over the next character, as in o̊. See Inserting Accents.

@samp{TEXT}
     Highlight TEXT that is a literal example of a sequence of characters.  Used for single characters, for statements, and often for entire shell commands.  See @samp.

@sc{TEXT}
     Set TEXT in a printed output in THE SMALL CAPS FONT and set text in the Info file in uppercase letters. See Smallcaps.

@section TITLE
     Begin a section within a chapter.  In a printed manual, the section title is numbered and appears in the table of contents.  In Info, the title is underlined with equal signs.  See @section.

@set FLAG [STRING]
     Make FLAG active, causing the Texinfo formatting commands to format text between subsequent pairs of @ifset FLAG and @end ifset commands.  Optionally, set value of FLAG to STRING. See @set @clear @value.

@setchapternewpage ON-OFF-ODD
     Specify whether chapters start on new pages, and if so, whether on odd-numbered (right-hand) new pages.  See @setchapternewpage.

@setfilename INFO-FILE-NAME
     Provide a name to be used by the Info file.  This command is essential for TeX formatting as well, even though it produces no output. See @setfilename.

@settitle TITLE
     Provide a title for page headers in a printed manual. See @settitle.

@shortcontents
     Print a short table of contents.  Not relevant to Info, which uses menus rather than tables of contents.  A synonym for @summarycontents.  See Generating a Table of Contents.

@shorttitlepage{TITLE}
     Generate a minimal title page.  See @titlepage.

@smallbook
     Cause TeX to produce a printed manual in a 7 by 9.25 inch format rather than the regular 8.5 by 11 inch format.  See Printing Small Books.  Also, see @smallexample and @smalllisp.

@smallexample
     Indent text to indicate an example.  Do not fill, select fixed-width font.  In @smallbook format, print text in a smaller font than with @example.  Pair with @end smallexample. See @smallexample and @smalllisp.

@smalllisp
     Begin an example of Lisp code.  Indent text, do not fill, select fixed-width font.  In @smallbook format, print text in a smaller font.  Pair with @end smalllisp.  See @smallexample and @smalllisp.

@sp N
     Skip N blank lines.  See @sp.

@ss{}
     Generate the German sharp-S es-zet letter, ß.  See Inserting Accents.

@strong TEXT
     Emphasize TEXT by typesetting it in a bold font for the printed manual and by surrounding it with asterisks for Info. See Emphasizing Text.

@subheading TITLE
     Print an unnumbered subsection-like heading in the text, but not in the table of contents of a printed manual.  In Info, the title is underlined with hyphens.  See @unnumberedsubsec @appendixsubsec @subheading.

@subsection TITLE
     Begin a subsection within a section.  In a printed manual, the subsection title is numbered and appears in the table of contents.  In Info, the title is underlined with hyphens.  See @subsection.

@subsubheading TITLE
     Print an unnumbered subsubsection-like heading in the text, but not in the table of contents of a printed manual.  In Info, the title is underlined with periods.  See The `subsub' Commands.

@subsubsection TITLE
     Begin a subsubsection within a subsection.  In a printed manual, the subsubsection title is numbered and appears in the table of contents.  In Info, the title is underlined with periods. See The `subsub' Commands.

@subtitle TITLE
     In a printed manual, set a subtitle in a normal sized font flush to the right-hand side of the page.  Not relevant to Info, which does not have title pages.  See @title @subtitle and @author Commands.

@summarycontents
     Print a short table of contents.  Not relevant to Info, which uses menus rather than tables of contents.  A synonym for @shortcontents.  See Generating a Table of Contents.

@syncodeindex FROM-INDEX INTO-INDEX
     Merge the index named in the first argument into the index named in the second argument, printing the entries from the first index in @code font.  See Combining Indices.

@synindex FROM-INDEX INTO-INDEX
     Merge the index named in the first argument into the index named in the second argument.  Do not change the font of FROM-INDEX entries.  See Combining Indices.

@t{TEXT}
     Print TEXT in a fixed-width, typewriter-like font. No effect in Info.  See Fonts.

@tab
     Separate columns in a multitable.  See Multitable Rows.

@table FORMATTING-COMMAND
     Begin a two-column table, using @item for each entry.  Write each first column entry on the same line as @item.  First column entries are printed in the font resulting from FORMATTING-COMMAND.  Pair with @end table. See Making a Two-column Table. Also see @ftable and @vtable, and @itemx.

@TeX{}
     Insert the logo TeX.  See Inserting TeX and ©.

@tex
     Enter TeX completely.  Pair with @end tex.  See Raw Formatter Commands.

@thischapter
@thischaptername
@thisfile
@thispage
@thistitle
     Only allowed in a heading or footing.  Stands for the number and name of the current chapter (in the format `Chapter 1: Title'), the chapter name only, the filename, the current page number, and the title of the document, respectively.  See How to Make Your Own Headings.

@tieaccent{CC}
     Generate a tie-after accent over the next two characters CC, as in `o͡o'.  See Inserting Accents.

@tindex ENTRY
     Add ENTRY to the index of data types.  See Defining the Entries of an Index.

@title TITLE
     In a printed manual, set a title flush to the left-hand side of the page in a larger than normal font and underline it with a black rule. Not relevant to Info, which does not have title pages.  See The @title @subtitle and @author Commands.

@titlefont{TEXT}
     In a printed manual, print TEXT in a larger than normal font. Not relevant to Info, which does not have title pages. See The @titlefont @center and @sp Commands.

@titlepage
     Indicate to Texinfo the beginning of the title page.  Write command on a line of its own.  Pair with @end titlepage.  Nothing between @titlepage and @end titlepage appears in Info. See @titlepage.

@today{}
     Insert the current date, in `1 Jan 1900' style.  See How to Make Your Own Headings.

@top TITLE
     In a Texinfo file to be formatted with makeinfo, identify the topmost @node line in the file, which must be written on the line immediately preceding the @top command.  Used for makeinfo's node pointer insertion feature.  The title is underlined with asterisks.  Both the @node line and the @top line normally should be enclosed by @ifinfo and @end ifinfo.  In TeX and texinfo-format-buffer, the @top command is merely a synonym for @unnumbered.  See Creating Pointers with makeinfo.

@u{C}
@ubaraccent{C}
@udotaccent{C}
     Generate a breve, underbar, or underdot accent, respectively, over or under the character C, as in ŏ, o̱, ọ.  See Inserting Accents.

@unnumbered TITLE
     In a printed manual, begin a chapter that appears without chapter numbers of any kind.  The title appears in the table of contents of a printed manual.  In Info, the title is underlined with asterisks. See @unnumbered and @appendix.

@unnumberedsec TITLE
     In a printed manual, begin a section that appears without section numbers of any kind.  The title appears in the table of contents of a printed manual.  In Info, the title is underlined with equal signs. See Section Commands.

@unnumberedsubsec TITLE
     In a printed manual, begin an unnumbered subsection within a chapter.  The title appears in the table of contents of a printed manual.  In Info, the title is underlined with hyphens. See @unnumberedsubsec @appendixsubsec @subheading.

@unnumberedsubsubsec TITLE
     In a printed manual, begin an unnumbered subsubsection within a chapter.  The title appears in the table of contents of a printed manual.  In Info, the title is underlined with periods. See The `subsub' Commands.

@uref{URL[, DISPLAYED-TEXT}
     Define a cross reference to an external uniform resource locator for the World Wide Web.  See @url.

@url{URL}
     Indicate text that is a uniform resource locator for the World Wide Web.  See @url.

@v{C}
     Generate check accent over the character C, as in ǒ. See Inserting Accents.

@value{FLAG}
     Replace FLAG with the value to which it is set by @set FLAG. See @set @clear @value.

@var{METASYNTACTIC-VARIABLE}
     Highlight a metasyntactic variable, which is something that stands for another piece of text.  See Indicating Metasyntactic Variables.

@vindex ENTRY
     Add ENTRY to the index of variables.  See Defining the Entries of an Index.

@vskip AMOUNT
     In a printed manual, insert whitespace so as to push text on the remainder of the page towards the bottom of the page.  Used in formatting the copyright page with the argument 0pt plus 1filll.  (Note spelling of filll.)  @vskip may be used only in contexts ignored for Info.  See The Copyright Page and Printed Permissions.

@vtable FORMATTING-COMMAND
     Begin a two-column table, using @item for each entry. Automatically enter each of the items in the first column into the index of variables.  Pair with @end vtable.  The same as @table, except for indexing.  See @ftable and @vtable.

@w{TEXT}
     Prevent TEXT from being split across two lines.  Do not end a paragraph that uses @w with an @refill command. See @w.

@xref{NODE-NAME, [ENTRY], [TOPIC-OR-TITLE], [INFO-FILE], [MANUAL]}
     Make a reference that starts with `See' in a printed manual.  Follow command with a punctuation mark.  Only the first argument is mandatory.  See @xref.

Tips and Hints
**************

Here are some tips for writing Texinfo documentation:

  * Write in the present tense, not in the past or the future.

  * Write actively!  For example, write ``We recommend that ...'' rather than ``It is recommended that ...''.

  * Use 70 or 72 as your fill column.  Longer lines are hard to read.

  * Include a copyright notice and copying permissions.

Index, Index, Index!
....................

Write many index entries, in different ways. Readers like indices; they are helpful and convenient.

Although it is easiest to write index entries as you write the body of the text, some people prefer to write entries afterwards.  In either case, write an entry before the paragraph to which it applies.  This way, an index entry points to the first page of a paragraph that is split across pages.

Here are more hints we have found valuable:

  * Write each index entry differently, so each entry refers to a different place in the document.

  * Write index entries only where a topic is discussed significantly.  For example, it is not useful to index ``debugging information'' in a chapter on reporting bugs.  Someone who wants to know about debugging information will certainly not find it in that chapter.

  * Consistently capitalize the first word of every concept index entry, or else consistently use lower case.  Terse entries often call for lower case; longer entries for capitalization.  Whichever case convention you use, please use one or the other consistently!  Mixing the two styles looks bad.

  * Always capitalize or use upper case for those words in an index for which this is proper, such as names of countries or acronyms.  Always use the appropriate case for case-sensitive names, such as those in C or Lisp.

  * Write the indexing commands that refer to a whole section immediately after the section command, and write the indexing commands that refer to the paragraph before the paragraph.

     In the example that follows, a blank line comes after the index entry for ``Leaping'':

          @section The Dog and the Fox
          @cindex Jumping, in general
          @cindex Leaping

          @cindex Dog, lazy, jumped over
          @cindex Lazy dog jumped over
          @cindex Fox, jumps over dog
          @cindex Quick fox jumps over dog
          The quick brown fox jumps over the lazy dog.

     (Note that the example shows entries for the same concept that are written in different ways---Lazy dog, and Dog, lazy---so readers can look up the concept in different ways.)

Blank Lines
...........

  * Insert a blank line between a sectioning command and the first following sentence or paragraph, or between the indexing commands associated with the sectioning command and the first following sentence or paragraph, as shown in the tip on indexing.  Otherwise, a formatter may fold title and paragraph together.

  * Always insert a blank line before an @table command and after an @end table command; but never insert a blank line after an @table command or before an @end table command.

     For example,

          Types of fox:

          @table @samp
          @item Quick
          Jump over lazy dogs.

          @item Brown
          Also jump over lazy dogs.
          @end table

          @noindent
          On the other hand, ...

     Insert blank lines before and after @itemize ... @end itemize and @enumerate ... @end enumerate in the same way.

Complete Phrases
................

Complete phrases are easier to read than ...

  * Write entries in an itemized list as complete sentences; or at least, as complete phrases.  Incomplete expressions ... awkward ... like this.

  * Write the prefatory sentence or phrase for a multi-item list or table as a complete expression.  Do not write ``You can set:''; instead, write ``You can set these variables:''.  The former expression sounds cut off.

Editions, Dates and Versions
............................

Write the edition and version numbers and date in three places in every manual:

 1. In the first @ifinfo section, for people reading the Texinfo file.

 2. In the @titlepage section, for people reading the printed manual.

 3. In the `Top' node, for people reading the Info file.

Also, it helps to write a note before the first @ifinfo section to explain what you are doing.

For example:

     @c ===> NOTE! <==
     @c Specify the edition and version numbers and date
     @c in *three* places:
     @c   1. First ifinfo section  2. title page  3. top node
     @c To find the locations, search for !!set

     @ifinfo
     @c !!set edition, date, version
     This is Edition 4.03, January 1992,
     of the @cite{GDB Manual} for GDB Version 4.3.
     ...

---or use @set and @value (see @value Example).

Definition Commands
...................

Definition commands are @deffn, @defun, @defmac, and the like, and enable you to write descriptions in a uniform format.

  * Write just one definition command for each entity you define with a definition command.  The automatic indexing feature creates an index entry that leads the reader to the definition.

  * Use @table ... @end table in an appendix that contains a summary of functions, not @deffn or other definition commands.

Capitalization
..............

  * Capitalize ``Texinfo''; it is a name.  Do not write the x or i in upper case.

  * Capitalize ``Info''; it is a name.

  * Write TeX using the @TeX{} command.  Note the uppercase T and X.  This command causes the formatters to typeset the name according to the wishes of Donald Knuth, who wrote TeX.

Spaces
......

Do not use spaces to format a Texinfo file, except inside of @example ... @end example and similar commands.

For example, TeX fills the following:

         @kbd{C-x v}
         @kbd{M-x vc-next-action}
            Perform the next logical operation
            on the version-controlled file
            corresponding to the current buffer.

so it looks like this:

     `C-x v' `M-x vc-next-action' Perform the next logical operation on the version-controlled file corresponding to the current buffer.

In this case, the text should be formatted with @table, @item, and @itemx, to create a table.

@code, @samp, @var, and ---
...........................

  * Use @code around Lisp symbols, including command names. For example,

          The main function is @code{vc-next-action}, ...

  * Avoid putting letters such as s immediately after an @code.  Such letters look bad.

  * Use @var around meta-variables.  Do not write angle brackets around them.

  * Use three hyphens in a row, ---, to indicate a long dash.  TeX typesets these as a long dash and the Info formatters reduce three hyphens to two.

Periods Outside of Quotes
.........................

Place periods and other punctuation marks outside of quotations, unless the punctuation is part of the quotation.  This practice goes against publishing conventions in the United States, but enables the reader to distinguish between the contents of the quotation and the whole passage.

For example, you should write the following sentence with the period outside the end quotation marks:

     Evidently, au is an abbreviation for ``author''.

since au does not serve as an  abbreviation for author. (with a period following the word).

Introducing New Terms
.....................

  * Introduce new terms so that a reader who does not know them can understand them from context; or write a definition for the term.

     For example, in the following, the terms ``check in'', ``register'' and ``delta'' are all appearing for the first time; the example sentence should be rewritten so they are understandable.

          The major function assists you in checking in a file to your version control system and registering successive sets of changes to it as deltas.

  * Use the @dfn command around a word being introduced, to indicate that the reader should not expect to know the meaning already, and should expect to learn the meaning from this passage.

@pxref
......

Absolutely never use @pxref except in the special context for which it is designed: inside parentheses, with the closing parenthesis following immediately after the closing brace.  One formatter automatically inserts closing punctuation and the other does not.  This means that the output looks right both in printed output and in an Info file, but only when the command is used inside parentheses.

Invoking from a Shell
.....................

You can invoke programs such as Emacs, GCC, and gawk from a shell.  The documentation for each program should contain a section that describes this.  Unfortunately, if the node names and titles for these sections are all different, readers find it hard to search for the section.

Name such sections with a phrase beginning with the word `Invoking ...', as in `Invoking Emacs'; this way users can find the section easily.

ANSI C Syntax
.............

When you use @example to describe a C function's calling conventions, use the ANSI C syntax, like this:

     void dld_init (char *@var{path});

And in the subsequent discussion, refer to the argument values by writing the same argument names, again highlighted with @var.

Avoid the obsolete style that looks like this:

     #include <dld.h>

     dld_init (path)
     char *path;

Also, it is best to avoid writing #include above the declaration just to indicate that the function is declared in a header file.  The practice may give the misimpression that the #include belongs near the declaration of the function.  Either state explicitly which header file holds the declaration or, better yet, name the header file used for a group of functions at the beginning of the section that describes the functions.

Bad Examples
............

Here are several examples of bad writing to avoid:

In this example, say, `` ... you must @dfn{check in} the new version.''  That flows better.

     When you are done editing the file, you must perform a @dfn{check in}.

In the following example, say, ``... makes a unified interface such as VC mode possible.''

     SCCS, RCS and other version-control systems all perform similar functions in broadly similar ways (it is this resemblance which makes a unified control mode like this possible).

And in this example, you should specify what `it' refers to:

     If you are working with other people, it assists in coordinating everyone's changes so they do not step on each other.

And Finally ...
...............

  * Pronounce TeX as if the X were a Greek `chi', as the last sound in the name `Bach'.  But pronounce Texinfo as in `speck': ``teckinfo''.

  * Write notes for yourself at the very end of a Texinfo file after the @bye.  None of the formatters process text after the @bye; it is as if the text were within @ignore ... @end ignore.

A Sample Texinfo File
*********************

Here is a complete, short sample Texinfo file, without any commentary. You can see this file, with comments, in the first chapter. See A Short Sample Texinfo File.

     \input texinfo   @c -*-texinfo-*-
     @c %**start of header
     @setfilename sample.info
     @settitle Sample Document
     @c %**end of header

     @setchapternewpage odd

     @ifinfo
     This is a short example of a complete Texinfo file.

     Copyright 1990 Free Software Foundation, Inc.
     @end ifinfo

     @titlepage
     @sp 10
     @comment The title is printed in a large font.
     @center @titlefont{Sample Title}

     @c The following two commands start the copyright page.
     @page
     @vskip 0pt plus 1filll
     Copyright @copyright{} 1990 Free Software Foundation, Inc.
     @end titlepage

     @node    Top,       First Chapter,         , (dir)
     @comment node-name, next,          previous, up

     @menu
     * First Chapter::    The first chapter is the
                          only chapter in this sample.
     * Concept Index::    This index has two entries.
     @end menu

     @node    First Chapter, Concept Index, Top,      Top
     @comment node-name,     next,          previous, up
     @chapter First Chapter
     @cindex Sample index entry

     This is the contents of the first chapter.
     @cindex Another sample index entry

     Here is a numbered list.

     @enumerate
     @item
     This is the first item.

     @item
     This is the second item.
     @end enumerate

     The @code{makeinfo} and @code{texinfo-format-buffer}
     commands transform a Texinfo file such as this into
     an Info file; and @TeX{} typesets it for a printed
     manual.

     @node    Concept Index,    ,  First Chapter, Top
     @comment node-name,    next,  previous,      up
     @unnumbered Concept Index

     @printindex cp

     @contents
     @bye

Sample Permissions
******************

Texinfo files should contain sections that tell the readers that they have the right to copy and distribute the Texinfo file, the Info file, and the printed manual.

Also, if you are writing a manual about software, you should explain that the software is free and either include the GNU General Public License (GPL) or provide a reference to it.  See Distribution (The GNU Emacs Manual), for an example of the text that could be used in the software ``Distribution'', ``General Public License'', and ``NO WARRANTY'' sections of a document.  See Texinfo Copying Conditions, for an example of a brief explanation of how the copying conditions provide you with rights.

Inserting Permissions
=====================

In a Texinfo file, the first @ifinfo section usually begins with a line that says what the file documents.  This is what a person reading the unprocessed Texinfo file or using the advanced Info command g * sees first.  See Advanced Info commands (info), for more information. (A reader using the regular Info commands usually starts reading at the first node and skips this first section, which is not in a node.)

In the @ifinfo section, the summary sentence is followed by a copyright notice and then by the copying permission notice.  One of the copying permission paragraphs is enclosed in @ignore and @end ignore commands.  This paragraph states that the Texinfo file can be processed through TeX and printed, provided the printed manual carries the proper copying permission notice.  This paragraph is not made part of the Info file since it is not relevant to the Info file; but it is a mandatory part of the Texinfo file since it permits people to process the Texinfo file in TeX and print the results.

In the printed manual, the Free Software Foundation copying permission notice follows the copyright notice and publishing information and is located within the region delineated by the @titlepage and @end titlepage commands.  The copying permission notice is exactly the same as the notice in the @ifinfo section except that the paragraph enclosed in @ignore and @end ignore commands is not part of the notice.

To make it simple to insert a permission notice into each section of the Texinfo file, sample permission notices for each section are reproduced in full below.

Note that you may need to specify the correct name of a section mentioned in the permission notice.  For example, in The GDB Manual, the name of the section referring to the General Public License is called the ``GDB General Public License'', but in the sample shown below, that section is referred to generically as the ``GNU General Public License''.  If the Texinfo file does not carry a copy of the General Public License, leave out the reference to it, but be sure to include the rest of the sentence.

ifinfo Copying Permissions
==========================

In the @ifinfo section of a Texinfo file, the standard Free Software Foundation permission notice reads as follows:

     This file documents ...

     Copyright 1997 Free Software Foundation, Inc.

     Permission is granted to make and distribute verbatim
     copies of this manual provided the copyright notice and
     this permission notice are preserved on all copies.

     @ignore
     Permission is granted to process this file through TeX
     and print the results, provided the printed document
     carries a copying permission notice identical to this
     one except for the removal of this paragraph (this
     paragraph not being relevant to the printed manual).

     @end ignore
     Permission is granted to copy and distribute modified
     versions of this manual under the conditions for
     verbatim copying, provided also that the sections
     entitled ``Copying'' and ``GNU General Public License''
     are included exactly as in the original, and provided
     that the entire resulting derived work is distributed
     under the terms of a permission notice identical to this
     one.

     Permission is granted to copy and distribute
     translations of this manual into another language,
     under the above conditions for modified versions,
     except that this permission notice may be stated in a
     translation approved by the Free Software Foundation.

Titlepage Copying Permissions
=============================

In the @titlepage section of a Texinfo file, the standard Free Software Foundation copying permission notice follows the copyright notice and publishing information.  The standard phrasing is as follows:

     Permission is granted to make and distribute verbatim
     copies of this manual provided the copyright notice and
     this permission notice are preserved on all copies.

     Permission is granted to copy and distribute modified
     versions of this manual under the conditions for
     verbatim copying, provided also that the sections
     entitled ``Copying'' and ``GNU General Public License''
     are included exactly as in the original, and provided
     that the entire resulting derived work is distributed
     under the terms of a permission notice identical to this
     one.

     Permission is granted to copy and distribute
     translations of this manual into another language,
     under the above conditions for modified versions,
     except that this permission notice may be stated in a
     translation approved by the Free Software Foundation.

Include Files
*************

When TeX or an Info formatting command sees an @include command in a Texinfo file, it processes the contents of the file named by the command and incorporates them into the DVI or Info file being created.  Index entries from the included file are incorporated into the indices of the output file.

Include files let you keep a single large document as a collection of conveniently small parts.

How to Use Include Files
========================

To include another file within a Texinfo file, write the @include command at the beginning of a line and follow it on the same line by the name of a file to be included.  For example:

     @include buffers.texi

An included file should simply be a segment of text that you expect to be included as is into the overall or outer Texinfo file; it should not contain the standard beginning and end parts of a Texinfo file.  In particular, you should not start an included file with a line saying \input texinfo; if you do, that phrase is inserted into the output file as is.  Likewise, you should not end an included file with an @bye command; nothing after @bye is formatted.

In the past, you were required to write an @setfilename line at the beginning of an included file, but no longer.  Now, it does not matter whether you write such a line.  If an @setfilename line exists in an included file, it is ignored.

Conventionally, an included file begins with an @node line that is followed by an @chapter line.  Each included file is one chapter.  This makes it easy to use the regular node and menu creating and updating commands to create the node pointers and menus within the included file.  However, the simple Emacs node and menu creating and updating commands do not work with multiple Texinfo files.  Thus you cannot use these commands to fill in the `Next', `Previous', and `Up' pointers of the @node line that begins the included file.  Also, you cannot use the regular commands to create a master menu for the whole file.  Either you must insert the menus and the `Next', `Previous', and `Up' pointers by hand, or you must use the GNU Emacs Texinfo mode command, texinfo-multiple-files-update, that is designed for @include files.

texinfo-multiple-files-update
=============================

GNU Emacs Texinfo mode provides the texinfo-multiple-files-update command.  This command creates or updates `Next', `Previous', and `Up' pointers of included files as well as those in the outer or overall Texinfo file, and it creates or updates a main menu in the outer file. Depending whether you call it with optional arguments, the command updates only the pointers in the first @node line of the included files or all of them:

M-x texinfo-multiple-files-update
     Called without any arguments:

       - Create or update the `Next', `Previous', and `Up' pointers of the first @node line in each file included in an outer or overall Texinfo file.

       - Create or update the `Top' level node pointers of the outer or overall file.

       - Create or update a main menu in the outer file.

C-u M-x texinfo-multiple-files-update
     Called with C-u as a prefix argument:

       - Create or update pointers in the first @node line in each included file.

       - Create or update the `Top' level node pointers of the outer file.

       - Create and insert a master menu in the outer file.  The master menu is made from all the menus in all the included files.

C-u 8 M-x texinfo-multiple-files-update
     Called with a numeric prefix argument, such as C-u 8:

       - Create or update all the `Next', `Previous', and `Up' pointers of all the included files.

       - Create or update all the menus of all the included files.

       - Create or update the `Top' level node pointers of the outer or overall file.

       - And then create a master menu in the outer file.  This is similar to invoking texinfo-master-menu with an argument when you are working with just one file.

Note the use of the prefix argument in interactive use: with a regular prefix argument, just C-u, the texinfo-multiple-files-update command inserts a master menu; with a numeric prefix argument, such as C-u 8, the command updates every pointer and menu in all the files and then inserts a master menu.

Include File Requirements
=========================

If you plan to use the texinfo-multiple-files-update command, the outer Texinfo file that lists included files within it should contain nothing but the beginning and end parts of a Texinfo file, and a number of @include commands listing the included files.  It should not even include indices, which should be listed in an included file of their own.

Moreover, each of the included files must contain exactly one highest level node (conventionally, @chapter or equivalent), and this node must be the first node in the included file. Furthermore, each of these highest level nodes in each included file must be at the same hierarchical level in the file structure. Usually, each is an @chapter, an @appendix, or an @unnumbered node.  Thus, normally, each included file contains one, and only one, chapter or equivalent-level node.

The outer file should contain only one node, the `Top' node.  It should not contain any nodes besides the single `Top' node.  The texinfo-multiple-files-update command will not process them.

Sample File with @include
=========================

Here is an example of a complete outer Texinfo file with @include files within it before running texinfo-multiple-files-update, which would insert a main or master menu:

     \input texinfo @c -*-texinfo-*-
     @setfilename  include-example.info
     @settitle Include Example

     @setchapternewpage odd
     @titlepage
     @sp 12
     @center @titlefont{Include Example}
     @sp 2
     @center by Whom Ever

     @page
     @vskip 0pt plus 1filll
     Copyright @copyright{} 1997 Free Software Foundation, Inc.
     @end titlepage

     @ifinfo
     @node Top, First, , (dir)
     @top Master Menu
     @end ifinfo

     @include foo.texinfo
     @include bar.texinfo
     @include concept-index.texinfo

     @summarycontents
     @contents

     @bye

An included file, such as foo.texinfo, might look like this:

     @node First, Second, , Top
     @chapter First Chapter

     Contents of first chapter ...

The full contents of concept-index.texinfo might be as simple as this:

     @node Concept Index, , Second, Top
     @unnumbered Concept Index

     @printindex cp

The outer Texinfo source file for The GNU Emacs Lisp Reference Manual is named elisp.texi.  This outer file contains a master menu with 417 entries and a list of 41 @include files.

Evolution of Include Files
==========================

When Info was first created, it was customary to create many small Info files on one subject.  Each Info file was formatted from its own Texinfo source file.  This custom meant that Emacs did not need to make a large buffer to hold the whole of a large Info file when someone wanted information; instead, Emacs allocated just enough memory for the small Info file that contained the particular information sought.  This way, Emacs could avoid wasting memory.

References from one file to another were made by referring to the file name as well as the node name. (see Referring to Other Info Files.  Also, see @xref with Four and Five Arguments.)

Include files were designed primarily as a way to create a single, large printed manual out of several smaller Info files.  In a printed manual, all the references were within the same document, so TeX could automatically determine the references' page numbers.  The Info formatting commands used include files only for creating joint indices; each of the individual Texinfo files had to be formatted for Info individually.  (Each, therefore, required its own @setfilename line.)

However, because large Info files are now split automatically, it is no longer necessary to keep them small.

Nowadays, multiple Texinfo files are used mostly for large documents, such as The GNU Emacs Lisp Reference Manual, and for projects in which several different people write different sections of a document simultaneously.

In addition, the Info formatting commands have been extended to work with the @include command so as to create a single large Info file that is split into smaller files if necessary.  This means that you can write menus and cross references without naming the different Texinfo files.

Page Headings
*************

Most printed manuals contain headings along the top of every page except the title and copyright pages.  Some manuals also contain footings.  (Headings and footings have no meaning to Info, which is not paginated.)

Headings Introduced
===================

Texinfo provides standard page heading formats for manuals that are printed on one side of each sheet of paper and for manuals that are printed on both sides of the paper.  Typically, you will use these formats, but you can specify your own format if you wish.

In addition, you can specify whether chapters should begin on a new page, or merely continue the same page as the previous chapter; and if chapters begin on new pages, you can specify whether they must be odd-numbered pages.

By convention, a book is printed on both sides of each sheet of paper. When you open a book, the right-hand page is odd-numbered, and chapters begin on right-hand pages---a preceding left-hand page is left blank if necessary.  Reports, however, are often printed on just one side of paper, and chapters begin on a fresh page immediately following the end of the preceding chapter.  In short or informal reports, chapters often do not begin on a new page at all, but are separated from the preceding text by a small amount of whitespace.

The @setchapternewpage command controls whether chapters begin on new pages, and whether one of the standard heading formats is used. In addition, Texinfo has several heading and footing commands that you can use to generate your own heading and footing formats.

In Texinfo, headings and footings are single lines at the tops and bottoms of pages; you cannot create multiline headings or footings. Each header or footer line is divided into three parts: a left part, a middle part, and a right part.  Any part, or a whole line, may be left blank.  Text for the left part of a header or footer line is set flushleft; text for the middle part is centered; and, text for the right part is set flushright.

Standard Heading Formats
========================

Texinfo provides two standard heading formats, one for manuals printed on one side of each sheet of paper, and the other for manuals printed on both sides of the paper.

By default, nothing is specified for the footing of a Texinfo file, so the footing remains blank.

The standard format for single-sided printing consists of a header line in which the left-hand part contains the name of the chapter, the central part is blank, and the right-hand part contains the page number.

A single-sided page looks like this:

        _______________________
       |                       |
       | chapter   page number |
       |                       |
       | Start of text ...     |
       | ...                   |
       |                       |

The standard format for two-sided printing depends on whether the page number is even or odd.  By convention, even-numbered pages are on the left- and odd-numbered pages are on the right.  (TeX will adjust the widths of the left- and right-hand margins.  Usually, widths are correct, but during double-sided printing, it is wise to check that pages will bind properly---sometimes a printer will produce output in which the even-numbered pages have a larger right-hand margin than the odd-numbered pages.)

In the standard double-sided format, the left part of the left-hand (even-numbered) page contains the page number, the central part is blank, and the right part contains the title (specified by the @settitle command).  The left part of the right-hand (odd-numbered) page contains the name of the chapter, the central part is blank, and the right part contains the page number.

Two pages, side by side as in an open book, look like this:

        _______________________     _______________________
       |                       |   |                       |
       | page number     title |   | chapter   page number |
       |                       |   |                       |
       | Start of text ...     |   | More  text ...        |
       | ...                   |   | ...                   |
       |                       |   |                       |

The chapter name is preceded by the word ``Chapter'', the chapter number and a colon.  This makes it easier to keep track of where you are in the manual.

Specifying the Type of Heading
==============================

TeX does not begin to generate page headings for a standard Texinfo file until it reaches the @end titlepage command.  Thus, the title and copyright pages are not numbered.  The @end titlepage command causes TeX to begin to generate page headings according to a standard format specified by the @setchapternewpage command that precedes the @titlepage section.

There are four possibilities:

No @setchapternewpage command
     Cause TeX to specify the single-sided heading format, with chapters on new pages. This is the same as @setchapternewpage on.

@setchapternewpage on
     Specify the single-sided heading format, with chapters on new pages.

@setchapternewpage off
     Cause TeX to start a new chapter on the same page as the last page of the preceding chapter, after skipping some vertical whitespace.  Also cause TeX to typeset for single-sided printing.  (You can override the headers format with the @headings double command; see The @headings Command.)

@setchapternewpage odd
     Specify the double-sided heading format, with chapters on new pages.

Texinfo lacks an @setchapternewpage even command.

How to Make Your Own Headings
=============================

You can use the standard headings provided with Texinfo or specify your own.  By default, Texinfo has no footers, so if you specify them, the available page size for the main text will be slightly reduced.

Texinfo provides six commands for specifying headings and footings.  The @everyheading command and @everyfooting command generate page headers and footers that are the same for both even- and odd-numbered pages. The @evenheading command and @evenfooting command generate headers and footers for even-numbered (left-hand) pages; and the @oddheading command and @oddfooting command generate headers and footers for odd-numbered (right-hand) pages.

Write custom heading specifications in the Texinfo file immediately after the @end titlepage command.  Enclose your specifications between @iftex and @end iftex commands since the texinfo-format-buffer command may not recognize them.  Also, you must cancel the predefined heading commands with the @headings off command before defining your own specifications.

Here is how to tell TeX to place the chapter name at the left, the page number in the center, and the date at the right of every header for both even- and odd-numbered pages:

     @iftex
     @headings off
     @everyheading @thischapter @| @thispage @| @today{}
     @end iftex

You need to divide the left part from the central part and the central part from the right part by inserting @| between parts. Otherwise, the specification command will not be able to tell where the text for one part ends and the next part begins.

Each part can contain text or @-commands.  The text is printed as if the part were within an ordinary paragraph in the body of the page.  The @-commands replace themselves with the page number, date, chapter name, or whatever.

Here are the six heading and footing commands:

@everyheading LEFT @| CENTER @| RIGHT
@everyfooting LEFT @| CENTER @| RIGHT

     The `every' commands specify the format for both even- and odd-numbered pages.  These commands are for documents that are printed on one side of each sheet of paper, or for documents in which you want symmetrical headers or footers.

@evenheading LEFT @| CENTER @| RIGHT
@oddheading  LEFT @| CENTER @| RIGHT

@evenfooting LEFT @| CENTER @| RIGHT
@oddfooting  LEFT @| CENTER @| RIGHT

     The `even' and `odd' commands specify the format for even-numbered pages and odd-numbered pages.  These commands are for books and manuals that are printed on both sides of each sheet of paper.

Use the @this... series of @-commands to provide the names of chapters and sections and the page number.  You can use the @this... commands in the left, center, or right portions of headers and footers, or anywhere else in a Texinfo file so long as they are between @iftex and @end iftex commands.

Here are the @this... commands:

@thispage
     Expands to the current page number.

@thischaptername
     Expands to the name of the current chapter.

@thischapter
     Expands to the number and name of the current chapter, in the format `Chapter 1: Title'.

@thistitle
     Expands to the name of the document, as specified by the @settitle command.

@thisfile
     For @include files only: expands to the name of the current @include file.  If the current Texinfo source file is not an @include file, this command has no effect.  This command does not provide the name of the current Texinfo source file unless it is an @include file.  (see Include Files, for more information about @include files.)

You can also use the @today{} command, which expands to the current date, in `1 Jan 1900' format.

Other @-commands and text are printed in a header or footer just as if they were in the body of a page.  It is useful to incorporate text, particularly when you are writing drafts:

     @iftex
     @headings off
     @everyheading @emph{Draft!} @| @thispage @| @thischapter
     @everyfooting @| @| Version: 0.27: @today{}
     @end iftex

Beware of overlong titles: they may overlap another part of the header or footer and blot it out.

Formatting Mistakes
*******************

Besides mistakes in the content of your documentation, there are two kinds of mistake you can make with Texinfo:  you can make mistakes with @-commands, and you can make mistakes with the structure of the nodes and chapters.

Emacs has two tools for catching the @-command mistakes and two for catching structuring mistakes.

For finding problems with @-commands, you can run TeX or a region formatting command on the region that has a problem; indeed, you can run these commands on each region as you write it.

For finding problems with the structure of nodes and chapters, you can use C-c C-s (texinfo-show-structure) and the related occur command and you can use the M-x Info-validate command.

makeinfo Find Errors
====================

The makeinfo program does an excellent job of catching errors and reporting them---far better than texinfo-format-region or texinfo-format-buffer.  In addition, the various functions for automatically creating and updating node pointers and menus remove many opportunities for human error.

If you can, use the updating commands to create and insert pointers and menus.  These prevent many errors.  Then use makeinfo (or its Texinfo mode manifestations, makeinfo-region and makeinfo-buffer) to format your file and check for other errors.  This is the best way to work with Texinfo.  But if you cannot use makeinfo, or your problem is very puzzling, then you may want to use the tools described in this appendix.

Catching Errors with Info Formatting
====================================

After you have written part of a Texinfo file, you can use the texinfo-format-region or the makeinfo-region command to see whether the region formats properly.

Most likely, however, you are reading this section because for some reason you cannot use the makeinfo-region command; therefore, the rest of this section presumes that you are using texinfo-format-region.

If you have made a mistake with an @-command, texinfo-format-region will stop processing at or after the error and display an error message.  To see where in the buffer the error occurred, switch to the *Info Region* buffer; the cursor will be in a position that is after the location of the error.  Also, the text will not be formatted after the place where the error occurred (or more precisely, where it was detected).

For example, if you accidentally end a menu with the command @end menus with an `s' on the end, instead of with @end menu, you will see an error message that says:

     @end menus is not handled by texinfo

The cursor will stop at the point in the buffer where the error occurs, or not long after it.  The buffer will look like this:

     ---------- Buffer: *Info Region* ----------
     * Menu:

     * Using texinfo-show-structure::  How to use
                                       `texinfo-show-structure'
                                       to catch mistakes.
     * Running Info-Validate::         How to check for
                                       unreferenced nodes.
     @end menus
     -!-
     ---------- Buffer: *Info Region* ----------

The texinfo-format-region command sometimes provides slightly odd error messages.  For example, the following cross reference fails to format:

     (@xref{Catching Mistakes, for more info.)

In this case, texinfo-format-region detects the missing closing brace but displays a message that says Unbalanced parentheses rather than Unbalanced braces.  This is because the formatting command looks for mismatches between braces as if they were parentheses.

Sometimes texinfo-format-region fails to detect mistakes.  For example, in the following, the closing brace is swapped with the closing parenthesis:

     (@xref{Catching Mistakes), for more info.}

Formatting produces:

     (*Note for more info.: Catching Mistakes)

The only way for you to detect this error is to realize that the reference should have looked like this:

     (*Note Catching Mistakes::, for more info.)

Incidentally, if you are reading this node in Info and type f RET (Info-follow-reference), you will generate an error message that says:

     No such node: "Catching Mistakes) The only way ...

This is because Info perceives the example of the error as the first cross reference in this node and if you type a RET immediately after typing the Info f command, Info will attempt to go to the referenced node.  If you type f catch TAB RET, Info will complete the node name of the correctly written example and take you to the `Catching Mistakes' node.  (If you try this, you can return from the `Catching Mistakes' node by typing l (Info-last).)

Catching Errors with TeX Formatting
===================================

You can also catch mistakes when you format a file with TeX.

Usually, you will want to do this after you have run texinfo-format-buffer (or, better, makeinfo-buffer) on the same file, because texinfo-format-buffer sometimes displays error messages that make more sense than TeX.  (see Debugging with Info, for more information.)

For example, TeX was run on a Texinfo file, part of which is shown here:

     ---------- Buffer: texinfo.texi ----------
     name of the Texinfo file as an extension.  The
     @samp{??} are `wildcards' that cause the shell to
     substitute all the raw index files.  (@xref{sorting
     indices, for more information about sorting
     indices.)@refill
     ---------- Buffer: texinfo.texi ----------

(The cross reference lacks a closing brace.) TeX produced the following output, after which it stopped:

     ---------- Buffer: *tex-shell* ----------
     Runaway argument?
     {sorting indices, for more information about sorting
     indices.) @refill @ETC.
     ! Paragraph ended before @xref was complete.
     <to be read again>
                        @par
     l.27

     ?
     ---------- Buffer: *tex-shell* ----------

In this case, TeX produced an accurate and understandable error message:

     Paragraph ended before @xref was complete.

@par is an internal TeX command of no relevance to Texinfo. l.27 means that TeX detected the problem on line 27 of the Texinfo file.  The ? is the prompt TeX uses in this circumstance.

Unfortunately, TeX is not always so helpful, and sometimes you must truly be a Sherlock Holmes to discover what went wrong.

In any case, if you run into a problem like this, you can do one of three things.

 1. You can tell TeX to continue running and ignore just this error by typing RET at the ? prompt.

 2. You can tell TeX to continue running and to ignore all errors as best it can by typing r RET at the ? prompt.

     This is often the best thing to do.  However, beware: the one error may produce a cascade of additional error messages as its consequences are felt through the rest of the file.  To stop TeX when it is producing such an avalanche of error messages, type C-c (or C-c C-c, if you are running a shell inside Emacs).

 3. You can tell TeX to stop this run by typing x RET at the ? prompt.

Please note that if you are running TeX inside Emacs, you need to switch to the shell buffer and line at which TeX offers the ? prompt.

Sometimes TeX will format a file without producing error messages even though there is a problem.  This usually occurs if a command is not ended but TeX is able to continue processing anyhow.  For example, if you fail to end an itemized list with the @end itemize command, TeX will write a DVI file that you can print out.  The only error message that TeX will give you is the somewhat mysterious comment that

     (@end occurred inside a group at level 1)

However, if you print the DVI file, you will find that the text of the file that follows the itemized list is entirely indented as if it were part of the last item in the itemized list.  The error message is the way TeX says that it expected to find an @end command somewhere in the file; but that it could not determine where it was needed.

Another source of notoriously hard-to-find errors is a missing @end group command.  If you ever are stumped by incomprehensible errors, look for a missing @end group command first.

If the Texinfo file lacks header lines, TeX may stop in the beginning of its run and display output that looks like the following. The * indicates that TeX is waiting for input.

     This is TeX, Version 3.14159 (Web2c 7.0)
     (test.texinfo [1])
     *

In this case, simply type \end RET after the asterisk.  Then write the header lines in the Texinfo file and run the TeX command again. (Note the use of the backslash, \.  TeX uses \ instead of @; and in this circumstance, you are working directly with TeX, not with Texinfo.)

Using texinfo-show-structure
============================

It is not always easy to keep track of the nodes, chapters, sections, and subsections of a Texinfo file.  This is especially true if you are revising or adding to a Texinfo file that someone else has written.

In GNU Emacs, in Texinfo mode, the texinfo-show-structure command lists all the lines that begin with the @-commands that specify the structure: @chapter, @section, @appendix, and so on.  With an argument (C-u as prefix argument, if interactive), the command also shows the @node lines.  The texinfo-show-structure command is bound to C-c C-s in Texinfo mode, by default.

The lines are displayed in a buffer called the *Occur* buffer, indented by hierarchical level.  For example, here is a part of what was produced by running texinfo-show-structure on this manual:

      Lines matching "^@\\(chapter \\|sect\\|subs\\|subh\\|
      unnum\\|major\\|chapheading \\|heading \\|appendix\\)"
      in buffer texinfo.texi.
      ...
      4177:@chapter Nodes
      4198:    @heading Two Paths
      4231:    @section Node and Menu Illustration
      4337:    @section The @code{@@node} Command
      4393:        @subheading Choosing Node and Pointer Names
      4417:        @subsection How to Write an @code{@@node} Line
      4469:        @subsection @code{@@node} Line Tips
      ...

This says that lines 4337, 4393, and 4417 of texinfo.texi begin with the @section, @subheading, and @subsection commands respectively.  If you move your cursor into the *Occur* window, you can position the cursor over one of the lines and use the C-c C-c command (occur-mode-goto-occurrence), to jump to the corresponding spot in the Texinfo file.  See Using Occur (The GNU Emacs Manual), for more information about occur-mode-goto-occurrence.

The first line in the *Occur* window describes the regular expression specified by TEXINFO-HEADING-PATTERN.  This regular expression is the pattern that texinfo-show-structure looks for. See Using Regular Expressions (The GNU Emacs Manual), for more information.

When you invoke the texinfo-show-structure command, Emacs will display the structure of the whole buffer.  If you want to see the structure of just a part of the buffer, of one chapter, for example, use the C-x n n (narrow-to-region) command to mark the region.  (see Narrowing (The GNU Emacs Manual).)  This is how the example used above was generated.  (To see the whole buffer again, use C-x n w (widen).)

If you call texinfo-show-structure with a prefix argument by typing C-u C-c C-s, it will list lines beginning with @node as well as the lines beginning with the @-sign commands for @chapter, @section, and the like.

You can remind yourself of the structure of a Texinfo file by looking at the list in the *Occur* window; and if you have mis-named a node or left out a section, you can correct the mistake.

Using occur
===========

Sometimes the texinfo-show-structure command produces too much information.  Perhaps you want to remind yourself of the overall structure of a Texinfo file, and are overwhelmed by the detailed list produced by texinfo-show-structure.  In this case, you can use the occur command directly.  To do this, type

     M-x occur

and then, when prompted, type a regexp, a regular expression for the pattern you want to match.  (see Regular Expressions (The GNU Emacs Manual).)  The occur command works from the current location of the cursor in the buffer to the end of the buffer.  If you want to run occur on the whole buffer, place the cursor at the beginning of the buffer.

For example, to see all the lines that contain the word @chapter in them, just type @chapter.  This will produce a list of the chapters.  It will also list all the sentences with @chapter in the middle of the line.

If you want to see only those lines that start with the word @chapter, type ^@chapter when prompted by occur.  If you want to see all the lines that end with a word or phrase, end the last word with a $; for example, catching mistakes$.  This can be helpful when you want to see all the nodes that are part of the same chapter or section and therefore have the same `Up' pointer.

See Using Occur (The GNU Emacs Manual), for more information.

Finding Badly Referenced Nodes
==============================

You can use the Info-validate command to check whether any of the `Next', `Previous', `Up' or other node pointers fail to point to a node.  This command checks that every node pointer points to an existing node.  The Info-validate command works only on Info files, not on Texinfo files.

The makeinfo program validates pointers automatically, so you do not need to use the Info-validate command if you are using makeinfo.  You only may need to use Info-validate if you are unable to run makeinfo and instead must create an Info file using texinfo-format-region or texinfo-format-buffer, or if you write an Info file from scratch.

Running Info-validate
---------------------

To use Info-validate, visit the Info file you wish to check and type:

     M-x Info-validate

(Note that the Info-validate command requires an upper case `I'.  You may also need to create a tag table before running Info-validate.  See Tagifying.)

If your file is valid, you will receive a message that says ``File appears valid''.  However, if you have a pointer that does not point to a node, error messages will be displayed in a buffer called *problems in info file*.

For example, Info-validate was run on a test file that contained only the first node of this manual.  One of the messages said:

     In node "Overview", invalid Next: Texinfo Mode

This meant that the node called Overview had a `Next' pointer that did not point to anything (which was true in this case, since the test file had only one node in it).

Now suppose we add a node named Texinfo Mode to our test case but we do not specify a `Previous' for this node.  Then we will get the following error message:

     In node "Texinfo Mode", should have Previous: Overview

This is because every `Next' pointer should be matched by a `Previous' (in the node where the `Next' points) which points back.

Info-validate also checks that all menu entries and cross references point to actual nodes.

Note that Info-validate requires a tag table and does not work with files that have been split.  (The texinfo-format-buffer command automatically splits large files.)  In order to use Info-validate on a large file, you must run texinfo-format-buffer with an argument so that it does not split the Info file; and you must create a tag table for the unsplit file.

Creating an Unsplit File
------------------------

You can run Info-validate only on a single Info file that has a tag table.  The command will not work on the indirect subfiles that are generated when a master file is split.  If you have a large file (longer than 70,000 bytes or so), you need to run the texinfo-format-buffer or makeinfo-buffer command in such a way that it does not create indirect subfiles.  You will also need to create a tag table for the Info file.  After you have done this, you can run Info-validate and look for badly referenced nodes.

The first step is to create an unsplit Info file.  To prevent texinfo-format-buffer from splitting a Texinfo file into smaller Info files, give a prefix to the M-x texinfo-format-buffer command:

     C-u M-x texinfo-format-buffer

or else

     C-u C-c C-e C-b

When you do this, Texinfo will not split the file and will not create a tag table for it.

Tagifying a File
----------------

After creating an unsplit Info file, you must create a tag table for it.  Visit the Info file you wish to tagify and type:

     M-x Info-tagify

(Note the upper case I in Info-tagify.)  This creates an Info file with a tag table that you can validate.

The third step is to validate the Info file:

     M-x Info-validate

(Note the upper case I in Info-validate.) In brief, the steps are:

     C-u M-x texinfo-format-buffer
     M-x Info-tagify
     M-x Info-validate

After you have validated the node structure, you can rerun texinfo-format-buffer in the normal way so it will construct a tag table and split the file automatically, or you can make the tag table and split the file manually.

Splitting a File Manually
-------------------------

You should split a large file or else let the texinfo-format-buffer or makeinfo-buffer command do it for you automatically.  (Generally you will let one of the formatting commands do this job for you.  See Create an Info File.)

The split-off files are called the indirect subfiles.

Info files are split to save memory.  With smaller files, Emacs does not have make such a large buffer to hold the information.

If an Info file has more than 30 nodes, you should also make a tag table for it. See Using Info-validate, for information about creating a tag table.  (Again, tag tables are usually created automatically by the formatting command; you only need to create a tag table yourself if you are doing the job manually.  Most likely, you will do this for a large, unsplit file on which you have run Info-validate.)

Visit the Info file you wish to tagify and split and type the two commands:

     M-x Info-tagify
     M-x Info-split

(Note that the I in Info is upper case.)

When you use the Info-split command, the buffer is modified into a (small) Info file which lists the indirect subfiles.  This file should be saved in place of the original visited file.  The indirect subfiles are written in the same directory the original file is in, with names generated by appending - and a number to the original file name.

The primary file still functions as an Info file, but it contains just the tag table and a directory of subfiles.

Refilling Paragraphs
********************

The @refill command refills and, optionally, indents the first line of a paragraph. (Perhaps the command should have been called the @refillandindent command, but @refill is shorter and the name was chosen before indenting was possible.) The @refill command is no longer important, but we describe it here because you once needed it.  You will see it in many old Texinfo files.

Without refilling, paragraphs containing long @-constructs may look bad after formatting because the formatter removes @-commands and shortens some lines more than others.  In the past, neither the texinfo-format-region command nor the texinfo-format-buffer command refilled paragraphs automatically.  The @refill command had to be written at the end of every paragraph to cause these formatters to fill them.  (Both TeX and makeinfo have always refilled paragraphs automatically.)  Now, all the Info formatters automatically fill and indent those paragraphs that need to be filled and indented.

The @refill command causes texinfo-format-region and texinfo-format-buffer to refill a paragraph in the Info file after all the other processing has been done.  For this reason, you can not use @refill with a paragraph containing either @* or @w{ ... } since the refilling action will override those two commands.

The texinfo-format-region and texinfo-format-buffer commands now automatically append @refill to the end of each paragraph that should be filled.  They do not append @refill to the ends of paragraphs that contain @* or @w{ ...} and therefore do not refill or indent them.

@-Command Syntax
****************

The character @ is used to start special Texinfo commands. (It has the same meaning that \ has in plain TeX.)  Texinfo has four types of @-command:

1. Non-alphabetic commands.
     These commands consist of an @ followed by a punctuation mark or other character that is not part of the alphabet.  Non-alphabetic commands are almost always part of the text within a paragraph, and never take any argument.  The two characters (@ and the other one) are complete in themselves; none is followed by braces.  The non-alphabetic commands are: @., @:, @*, @SPACE, @TAB, @NL, @@, @{, and @}.

2. Alphabetic commands that do not require arguments.
     These commands start with @ followed by a word followed by left- and right-hand braces.  These commands insert special symbols in the document; they do not require arguments.  For example, @dots{} => ..., @equiv{} => ==, @TeX{} => `TeX', and @bullet{} => *.

3. Alphabetic commands that require arguments within braces.
     These commands start with @ followed by a letter or a word, followed by an argument within braces.  For example, the command @dfn indicates the introductory or defining use of a term; it is used as follows: In Texinfo, @@-commands are @dfn{mark-up} commands.

4. Alphabetic commands that occupy an entire line.
     These commands occupy an entire line.  The line starts with @, followed by the name of the command (a word); for example, @center or @cindex.  If no argument is needed, the word is followed by the end of the line.  If there is an argument, it is separated from the command name by a space.  Braces are not used.

Thus, the alphabetic commands fall into classes that have different argument syntaxes.  You cannot tell to which class a command belongs by the appearance of its name, but you can tell by the command's meaning: if the command stands for a glyph, it is in class 2 and does not require an argument; if it makes sense to use the command together with other text as part of a paragraph, the command is in class 3 and must be followed by an argument in braces; otherwise, it is in class 4 and uses the rest of the line as its argument.

The purpose of having a different syntax for commands of classes 3 and 4 is to make Texinfo files easier to read, and also to help the GNU Emacs paragraph and filling commands work properly.  There is only one exception to this rule: the command @refill, which is always used at the end of a paragraph immediately following the final period or other punctuation character.  @refill takes no argument and does not require braces.  @refill never confuses the Emacs paragraph commands because it cannot appear at the beginning of a line.

How to Obtain TeX
*****************

TeX is freely redistributable.  You can obtain TeX for Unix systems via anonymous ftp or on physical media.  The core material consists of the Web2c TeX distribution (http://www.tug.org/web2c).

Instructions for retrieval by anonymous ftp and information on other available distributions:

     ftp://ftp.tug.org/tex/unixtex.ftp
     http://www.tug.org/unixtex.ftp

The Free Software Foundation provides a core distribution on its Source Code CD-ROM suitable for printing Texinfo manuals; the University of Washington maintains and supports a tape distribution; the TeX Users Group co-sponsors a complete CD-ROM TeX distribution.

  * For the FSF Source Code CD-ROM, please contact:

          Free Software Foundation, Inc.
          59 Temple Place Suite 330
          Boston, MA   02111-1307
          USA

          Telephone: +1-617-542-5942
          Fax: (including Japan) +1-617-542-2652
          Free Dial Fax (in Japan):
                0031-13-2473 (KDD)
                0066-3382-0158 (IDC)
          Electronic mail: gnu@prep.ai.mit.edu

  * To order a complete distribution on CD-ROM, please see http://www.tug.org/tex-live.html.  (This distribution is also available by FTP; see the URL's above.)

  * To order a full distribution from the University of Washington on either a 1/4in 4-track QIC-24 cartridge or a 4mm DAT cartridge, send $210 to:

          Pierre A. MacKay
          Denny Hall, Mail Stop DH-10
          University of Washington
          Seattle, WA   98195
          USA
          Telephone: +1--206--543--2268
          Electronic mail: mackay@cs.washington.edu

     Please make checks payable to the University of Washington. Checks must be in U.S. dollars, drawn on a U.S. bank.  Overseas sites: please add to the base cost, if desired, $20.00 for shipment via air parcel post, or $30.00 for shipment via courier.

Many other TeX distributions are available; see http://www.tug.org/.

Command and Variable Index
**************************

This is an alphabetical list of all the @-commands, assorted Emacs Lisp functions, and several variables.  To make the list easier to use, the commands are listed without their preceding @.