xemacs-beta: man/make-stds.texi comparison

comparison man/make-stds.texi @ 398:74fd4e045ea6 r21-2-29

Import from CVS: tag r21-2-29

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date	Mon, 13 Aug 2007 11:13:30 +0200
parents	cc15677e0335
children	de805c49cfc1

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+:74fd4e045ea6
 @ifclear CODESTD
 chapter
 @end ifclear
 @end iftex
 describes conventions for writing the Makefiles for GNU programs.
+Using Automake will help you write a Makefile that follows these
+conventions.
 @menu
 * Makefile Basics::		General Conventions for Makefiles
 * Utilities in Makefiles::	Utilities in Makefiles
 * Command Variables::		Variables for Specifying Commands
 * Directory Variables::		Variables for Installation Directories
 * Standard Targets::		Standard Targets for Users
+* Install Command Categories::  Three categories of commands in the `install'
+rule: normal, pre-install and post-install.
 @end menu
 @node Makefile Basics
 @section General Conventions for Makefiles
 make, please make sure that it uses @file{./} if the program is built as
 part of the make or @file{$(srcdir)/} if the file is an unchanging part
 of the source code.  Without one of these prefixes, the current search
 path is used.
-The distinction between @file{./} and @file{$(srcdir)/} is important
+The distinction between @file{./} (the @dfn{build directory}) and
-when using the @samp{--srcdir} option to @file{configure}.  A rule of
+@file{$(srcdir)/} (the @dfn{source directory}) is important because
-the form:
+users can build in a separate directory using the @samp{--srcdir} option
+to @file{configure}.  A rule of the form:
 @smallexample
 foo.1 : foo.man sedscript
 sed -e sedscript foo.man > foo.1
 @end smallexample
 @noindent
-will fail when the current directory is not the source directory,
+will fail when the build directory is not the source directory, because
-because @file{foo.man} and @file{sedscript} are not in the current
+@file{foo.man} and @file{sedscript} are in the the source directory.
-directory.
 When using GNU @code{make}, relying on @samp{VPATH} to find the source
 file will work in the case where there is a single dependency file,
 since the @code{make} automatic variable @samp{$<} will represent the
 source file wherever it is.  (Many versions of @code{make} set @samp{$<}
 @smallexample
 foo.1 : foo.man sedscript
 sed -e $(srcdir)/sedscript $(srcdir)/foo.man > $@@
 @end smallexample
+GNU distributions usually contain some files which are not source
+files---for example, Info files, and the output from Autoconf, Automake,
+Bison or Flex.  Since these files normally appear in the source
+directory, they should always appear in the source directory, not in the
+build directory.  So Makefile rules to update them should put the
+updated files in the source directory.
+However, if a file does not appear in the distribution, then the
+Makefile should not put it in the source directory, because building a
+program in ordinary circumstances should not modify the source directory
+in any way.
 Try to make the build and installation targets, at least (and all their
 subtargets) work correctly with a parallel @code{make}.
 @node Utilities in Makefiles
 @section Utilities in Makefiles
 special features of @code{ksh} or @code{bash}.
 The @code{configure} script and the Makefile rules for building and
 installation should not use any utilities directly except these:
+@c dd find
+@c gunzip gzip md5sum
+@c mkfifo mknod tee uname
 @example
-cat cmp cp echo egrep expr false grep
+cat cmp cp diff echo egrep expr false grep install-info
-ln mkdir mv pwd rm rmdir sed test touch true
+ln ls mkdir mv pwd rm rmdir sed sleep sort tar test touch true
 @end example
+The compression program @code{gzip} can be used in the @code{dist} rule.
 Stick to the generally supported options for these programs.  For
 example, don't use @samp{mkdir -p}, convenient as it may be, because
 most systems don't support it.
 and related programs, but should do so via @code{make} variables so that the
 user can substitute alternatives.  Here are some of the programs we
 mean:
 @example
-ar bison cc flex install ld lex
+ar bison cc flex install ld ldconfig lex
 make makeinfo ranlib texi2dvi yacc
 @end example
-Use the following @code{make} variables:
+Use the following @code{make} variables to run those programs:
 @example
-$(AR) $(BISON) $(CC) $(FLEX) $(INSTALL) $(LD) $(LEX)
+$(AR) $(BISON) $(CC) $(FLEX) $(INSTALL) $(LD) $(LDCONFIG) $(LEX)
 $(MAKE) $(MAKEINFO) $(RANLIB) $(TEXI2DVI) $(YACC)
 @end example
-When you use @code{ranlib}, you should make sure nothing bad happens if
+When you use @code{ranlib} or @code{ldconfig}, you should make sure
-the system does not have @code{ranlib}.  Arrange to ignore an error
+nothing bad happens if the system does not have the program in question.
-from that command, and print a message before the command to tell the
+Arrange to ignore an error from that command, and print a message before
-user that failure of the @code{ranlib} command does not mean a problem.
+the command to tell the user that failure of this command does not mean
-(The Autoconf @samp{AC_PROG_RANLIB} macro can help with this.)
+a problem.  (The Autoconf @samp{AC_PROG_RANLIB} macro can help with
+this.)
 If you use symbolic links, you should implement a fallback for systems
 that don't have symbolic links.
+Additional utilities that can be used via Make variables are:
+@example
+chgrp chmod chown mknod
+@end example
 It is ok to use other utilities in Makefile portions (or scripts)
 intended only for particular systems where you know those utilities
 exist.
 don't need to replace them with other programs.
 Each program-name variable should come with an options variable that is
 used to supply options to the program.  Append @samp{FLAGS} to the
 program-name variable name to get the options variable name---for
-example, @code{BISONFLAGS}.  (The name @code{CFLAGS} is an exception to
+example, @code{BISONFLAGS}.  (The names @code{CFLAGS} for the C
-this rule, but we keep it because it is standard.)  Use @code{CPPFLAGS}
+compiler, @code{YFLAGS} for yacc, and @code{LFLAGS} for lex, are
-in any compilation command that runs the preprocessor, and use
+exceptions to this rule, but we keep them because they are standard.)
-@code{LDFLAGS} in any compilation command that does linking as well as
+Use @code{CPPFLAGS} in any compilation command that runs the
-in any direct use of @code{ld}.
+preprocessor, and use @code{LDFLAGS} in any compilation command that
+does linking as well as in any direct use of @code{ld}.
 If there are C compiler options that @emph{must} be used for proper
 compilation of certain files, do not include them in @code{CFLAGS}.
 Users expect to be able to specify @code{CFLAGS} freely themselves.
 Instead, arrange to pass the necessary options to the C compiler
 Put @code{CFLAGS} last in the compilation command, after other variables
 containing compiler options, so the user can use @code{CFLAGS} to
 override the others.
+@code{CFLAGS} should be used in every invocation of the C compiler,
+both those which do compilation and those which do linking.
 Every Makefile should define the variable @code{INSTALL}, which is the
 basic command for installing a file into the system.
 Every Makefile should also define the variables @code{INSTALL_PROGRAM}
 and @code{INSTALL_DATA}.  (The default for each of these should be
 respectively.  Use these variables as follows:
 @example
 $(INSTALL_PROGRAM) foo $(bindir)/foo
 $(INSTALL_DATA) libfoo.a $(libdir)/libfoo.a
+@end example
+Optionally, you may prepend the value of @code{DESTDIR} to the target
+filename.  Doing this allows the installer to create a snapshot of the
+installation to be copied onto the real target filesystem later.  Do not
+set the value of @code{DESTDIR} in your Makefile, and do not include it
+in any installed files.  With support for @code{DESTDIR}, the above
+examples become:
+@example
+$(INSTALL_PROGRAM) foo $(DESTDIR)$(bindir)/foo
+$(INSTALL_DATA) libfoo.a $(DESTDIR)$(libdir)/libfoo.a
 @end example
 @noindent
 Always use a file name, not a directory name, as the second argument of
 the installation commands.  Use a separate command for each file to be
 below.  The default value of @code{prefix} should be @file{/usr/local}.
 When building the complete GNU system, the prefix will be empty and
 @file{/usr} will be a symbolic link to @file{/}.
 (If you are using Autoconf, write it as @samp{@@prefix@@}.)
+Running @samp{make install} with a different value of @code{prefix}
+from the one used to build the program should @var{not} recompile
+the program.
 @item exec_prefix
 A prefix used in constructing the default values of some of the
 variables listed below.  The default value of @code{exec_prefix} should
 be @code{$(prefix)}.
 (If you are using Autoconf, write it as @samp{@@exec_prefix@@}.)
 Generally, @code{$(exec_prefix)} is used for directories that contain
 machine-specific files (such as executables and subroutine libraries),
 while @code{$(prefix)} is used directly for other directories.
+Running @samp{make install} with a different value of @code{exec_prefix}
+from the one used to build the program should @var{not} recompile the
+program.
 @end table
 Executable programs are installed in one of the following directories.
 @table @samp
 here.  All the files in this directory should be ordinary ASCII text
 files.  This directory should normally be @file{/usr/local/etc}, but
 write it as @file{$(prefix)/etc}.
 (If you are using Autoconf, write it as @samp{@@sysconfdir@@}.)
-@c rewritten to avoid overfull hbox --tower
+Do not install executables here in this directory (they probably belong
-Do not install executables
+in @file{$(libexecdir)} or @file{$(sbindir)}).  Also do not install
-@c here
+files that are modified in the normal course of their use (programs
-in this directory (they probably
+whose purpose is to change the configuration of the system excluded).
-belong in @file{$(libexecdir)} or @file{$(sbindir)}).  Also do not
+Those probably belong in @file{$(localstatedir)}.
-install files that are modified in the normal course of their use
-(programs whose purpose is to change the configuration of the system
-excluded).  Those probably belong in @file{$(localstatedir)}.
 @item sharedstatedir
 The directory for installing architecture-independent data files which
 the programs modify while they run.  This should normally be
 @file{/usr/local/com}, but write it as @file{$(prefix)/com}.
 The directory for installing the Info files for this package.  By
 default, it should be @file{/usr/local/info}, but it should be written
 as @file{$(prefix)/info}.
 (If you are using Autoconf, write it as @samp{@@infodir@@}.)
+@item lispdir
+The directory for installing any Emacs Lisp files in this package.  By
+default, it should be @file{/usr/local/share/emacs/site-lisp}, but it
+should be written as @file{$(prefix)/share/emacs/site-lisp}.
+If you are using Autoconf, write the default as @samp{@@lispdir@@}.
+In order to make @samp{@@lispdir@@} work, you need the following lines
+in your @file{configure.in} file:
+@example
+lispdir='$@{datadir@}/emacs/site-lisp'
+AC_SUBST(lispdir)
+@end example
 @item includedir
 @c rewritten to avoid overfull hbox --roland
 The directory for installing header files to be included by user
 programs with the C @samp{#include} preprocessor directive.  This
 should normally be @file{/usr/local/include}, but write it as
 @file{$(prefix)/include}.
 (If you are using Autoconf, write it as @samp{@@includedir@@}.)
-Most compilers other than GCC do not look for header files in
+Most compilers other than GCC do not look for header files in directory
 @file{/usr/local/include}.  So installing the header files this way is
 only useful with GCC.  Sometimes this is not a problem because some
 libraries are only really intended to work with GCC.  But some libraries
 are intended to work with other compilers.  They should install their
 header files in two places, one specified by @code{includedir} and one
 Here is a sample rule to install an Info file:
 @comment This example has been carefully formatted for the Make manual.
 @comment Please do not reformat it without talking to roland@gnu.ai.mit.edu.
 @smallexample
-$(infodir)/foo.info: foo.info
+$(DESTDIR)$(infodir)/foo.info: foo.info
+$(POST_INSTALL)
 # There may be a newer info file in . than in srcdir.
 -if test -f foo.info; then d=.; \
 else d=$(srcdir); fi; \
-$(INSTALL_DATA) $$d/foo.info $@@; \
+$(INSTALL_DATA) $$d/foo.info $(DESTDIR)$@@; \
 # Run install-info only if it exists.
 # Use `if' instead of just prepending `-' to the
 # line so we notice real errors from install-info.
 # We use `$(SHELL) -c' because some shells do not
 # fail gracefully when there is an unknown command.
 if $(SHELL) -c 'install-info --version' \
 >/dev/null 2>&1; then \
-install-info --dir-file=$(infodir)/dir \
+install-info --dir-file=$(DESTDIR)$(infodir)/dir \
-$(infodir)/foo.info; \
+$(DESTDIR)$(infodir)/foo.info; \
 else true; fi
 @end smallexample
+When writing the @code{install} target, you must classify all the
+commands into three categories: normal ones, @dfn{pre-installation}
+commands and @dfn{post-installation} commands.  @xref{Install Command
+Categories}.
 @item uninstall
-Delete all the installed files that the @samp{install} target would
+Delete all the installed files---the copies that the @samp{install}
-create (but not the noninstalled files such as @samp{make all} would
+target creates.
-create).
 This rule should not modify the directories where compilation is done,
 only the directories where files are installed.
+The uninstallation commands are divided into three categories, just like
+the installation commands.  @xref{Install Command Categories}.
 @item install-strip
 Like @code{install}, but strip the executable files while installing
-them.  The definition of this target can be very simple:
+them.  In many cases, the definition of this target can be very simple:
 @smallexample
 install-strip:
 $(MAKE) INSTALL_PROGRAM='$(INSTALL_PROGRAM) -s' \
 install
 @noindent
 You must define the variable @code{MAKEINFO} in the Makefile.  It should
 run the @code{makeinfo} program, which is part of the Texinfo
 distribution.
+Normally a GNU distribution comes with Info files, and that means the
+Info files are present in the source directory.  Therefore, the Make
+rule for an info file should update it in the source directory.  When
+users build the package, ordinarily Make will not update the Info files
+because they will already be up to date.
 @item dvi
 Generate DVI files for all Texinfo documentation.
 For example:
 @smallexample
 The easiest way to do this is to create a subdirectory appropriately
 named, use @code{ln} or @code{cp} to install the proper files in it, and
 then @code{tar} that subdirectory.
-Compress the tar file with @code{gzip}.  For example, the actual
+Compress the tar file file with @code{gzip}.  For example, the actual
 distribution file for GCC version 1.40 is called @file{gcc-1.40.tar.gz}.
 The @code{dist} target should explicitly depend on all non-source files
 that are in the distribution, to make sure they are up to date in the
 distribution.
 @end smallexample
 This rule should not modify the directories where compilation is done.
 It should do nothing but create installation directories.
 @end table
+@node Install Command Categories
+@section Install Command Categories
+@cindex pre-installation commands
+@cindex post-installation commands
+When writing the @code{install} target, you must classify all the
+commands into three categories: normal ones, @dfn{pre-installation}
+commands and @dfn{post-installation} commands.
+Normal commands move files into their proper places, and set their
+modes.  They may not alter any files except the ones that come entirely
+from the package they belong to.
+Pre-installation and post-installation commands may alter other files;
+in particular, they can edit global configuration files or data bases.
+Pre-installation commands are typically executed before the normal
+commands, and post-installation commands are typically run after the
+normal commands.
+The most common use for a post-installation command is to run
+@code{install-info}.  This cannot be done with a normal command, since
+it alters a file (the Info directory) which does not come entirely and
+solely from the package being installed.  It is a post-installation
+command because it needs to be done after the normal command which
+installs the package's Info files.
+Most programs don't need any pre-installation commands, but we have the
+feature just in case it is needed.
+To classify the commands in the @code{install} rule into these three
+categories, insert @dfn{category lines} among them.  A category line
+specifies the category for the commands that follow.
+A category line consists of a tab and a reference to a special Make
+variable, plus an optional comment at the end.  There are three
+variables you can use, one for each category; the variable name
+specifies the category.  Category lines are no-ops in ordinary execution
+because these three Make variables are normally undefined (and you
+@emph{should not} define them in the makefile).
+Here are the three possible category lines, each with a comment that
+explains what it means:
+@smallexample
+$(PRE_INSTALL)     # @r{Pre-install commands follow.}
+$(POST_INSTALL)    # @r{Post-install commands follow.}
+$(NORMAL_INSTALL)  # @r{Normal commands follow.}
+@end smallexample
+If you don't use a category line at the beginning of the @code{install}
+rule, all the commands are classified as normal until the first category
+line.  If you don't use any category lines, all the commands are
+classified as normal.
+These are the category lines for @code{uninstall}:
+@smallexample
+$(PRE_UNINSTALL)     # @r{Pre-uninstall commands follow.}
+$(POST_UNINSTALL)    # @r{Post-uninstall commands follow.}
+$(NORMAL_UNINSTALL)  # @r{Normal commands follow.}
+@end smallexample
+Typically, a pre-uninstall command would be used for deleting entries
+from the Info directory.
+If the @code{install} or @code{uninstall} target has any dependencies
+which act as subroutines of installation, then you should start
+@emph{each} dependency's commands with a category line, and start the
+main target's commands with a category line also.  This way, you can
+ensure that each command is placed in the right category regardless of
+which of the dependencies actually run.
+Pre-installation and post-installation commands should not run any
+programs except for these:
+@example
+[ basename bash cat chgrp chmod chown cmp cp dd diff echo
+egrep expand expr false fgrep find getopt grep gunzip gzip
+hostname install install-info kill ldconfig ln ls md5sum
+mkdir mkfifo mknod mv printenv pwd rm rmdir sed sort tee
+test touch true uname xargs yes
+@end example
+@cindex binary packages
+The reason for distinguishing the commands in this way is for the sake
+of making binary packages.  Typically a binary package contains all the
+executables and other files that need to be installed, and has its own
+method of installing them---so it does not need to run the normal
+installation commands.  But installing the binary package does need to
+execute the pre-installation and post-installation commands.
+Programs to build binary packages work by extracting the
+pre-installation and post-installation commands.  Here is one way of
+extracting the pre-installation commands:
+@smallexample
+make -n install -o all \
+PRE_INSTALL=pre-install \
+POST_INSTALL=post-install \
+NORMAL_INSTALL=normal-install \
+| gawk -f pre-install.awk
+@end smallexample
+@noindent
+where the file @file{pre-install.awk} could contain this:
+@smallexample
+$0 ~ /^\t[ \t]*(normal_install|post_install)[ \t]*$/ @{on = 0@}
+on @{print $0@}
+$0 ~ /^\t[ \t]*pre_install[ \t]*$/ @{on = 1@}
+@end smallexample
+The resulting file of pre-installation commands is executed as a shell
+script as part of installing the binary package.

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comparison man/make-stds.texi @ 398:74fd4e045ea6 r21-2-29