view man/lispref/x-windows.texi @ 5353:38e24b8be4ea

Improve the lexical scoping in #'block, #'return-from. lisp/ChangeLog addition: 2011-02-07 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el: * bytecomp.el (byte-compile-initial-macro-environment): Shadow `block', `return-from' here, we implement them differently when byte-compiling. * bytecomp.el (byte-compile-active-blocks): New. * bytecomp.el (byte-compile-block-1): New. * bytecomp.el (byte-compile-return-from-1): New. * bytecomp.el (return-from-1): New. * bytecomp.el (block-1): New. These are two aliases that exist to have their own associated byte-compile functions, which functions implement `block' and `return-from'. * cl-extra.el (cl-macroexpand-all): Fix a bug here when macros in the environment have been compiled. * cl-macs.el (block): * cl-macs.el (return): * cl-macs.el (return-from): Be more careful about lexical scope in these macros. * cl.el: * cl.el ('cl-block-wrapper): Removed. * cl.el ('cl-block-throw): Removed. These aren't needed in code generated by this XEmacs. They shouldn't be needed in code generated by XEmacs 21.4, but if it turns out the packages do need them, we can put them back. 2011-01-30 Mike Sperber <mike@xemacs.org> * font-lock.el (font-lock-fontify-pending-extents): Don't fail if `font-lock-mode' is unset, which can happen in the middle of `revert-buffer'. 2011-01-23 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (delete): * cl-macs.el (delq): * cl-macs.el (remove): * cl-macs.el (remq): Don't use the compiler macro if these functions were given the wrong number of arguments, as happens in lisp-tests.el. * cl-seq.el (remove, remq): Removed. I added these to subr.el, and forgot to remove them from here. 2011-01-22 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-setq, byte-compile-set): Remove kludge allowing keywords' values to be set, all the code that does that is gone. * cl-compat.el (elt-satisfies-test-p): * faces.el (set-face-parent): * faces.el (face-doc-string): * gtk-font-menu.el: * gtk-font-menu.el (gtk-reset-device-font-menus): * msw-font-menu.el: * msw-font-menu.el (mswindows-reset-device-font-menus): * package-get.el (package-get-installedp): * select.el (select-convert-from-image-data): * sound.el: * sound.el (load-sound-file): * x-font-menu.el (x-reset-device-font-menus-core): Don't quote keywords, they're self-quoting, and the win from backward-compatibility is sufficiently small now that the style problem overrides it. 2011-01-22 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (block, return-from): Require that NAME be a symbol in these macros, as always documented in the #'block docstring and as required by Common Lisp. * descr-text.el (unidata-initialize-unihan-database): Correct the use of non-symbols in #'block and #'return-from in this function. 2011-01-15 Aidan Kehoe <kehoea@parhasard.net> * cl-extra.el (concatenate): Accept more complicated TYPEs in this function, handing the sequences over to #'coerce if we don't understand them here. * cl-macs.el (inline): Don't proclaim #'concatenate as inline, its compiler macro is more useful than doing that. 2011-01-11 Aidan Kehoe <kehoea@parhasard.net> * subr.el (delete, delq, remove, remq): Move #'remove, #'remq here, they don't belong in cl-seq.el; move #'delete, #'delq here from fns.c, implement them in terms of #'delete*, allowing support for sequences generally. * update-elc.el (do-autoload-commands): Use #'delete*, not #'delq here, now the latter's no longer dumped. * cl-macs.el (delete, delq): Add compiler macros transforming #'delete and #'delq to #'delete* calls. 2011-01-10 Aidan Kehoe <kehoea@parhasard.net> * dialog.el (make-dialog-box): Correct a misplaced parenthesis here, thank you Mats Lidell in 87zkr9gqrh.fsf@mail.contactor.se ! 2011-01-02 Aidan Kehoe <kehoea@parhasard.net> * dialog.el (make-dialog-box): * list-mode.el (display-completion-list): These functions used to use cl-parsing-keywords; change them to use defun* instead, fixing the build. (Not sure what led to me not including this change in d1b17a33450b!) 2011-01-02 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (define-star-compiler-macros): Make sure the form has ITEM and LIST specified before attempting to change to calls with explicit tests; necessary for some tests in lisp-tests.el to compile correctly. (stable-union, stable-intersection): Add compiler macros for these functions, in the same way we do for most of the other functions in cl-seq.el. 2011-01-01 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (dolist, dotimes, do-symbols, macrolet) (symbol-macrolet): Define these macros with defmacro* instead of parsing the argument list by hand, for the sake of style and readability; use backquote where appropriate, instead of calling #'list and and friends, for the same reason. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * x-misc.el (device-x-display): Provide this function, documented in the Lispref for years, but not existing previously. Thank you Julian Bradfield, thank you Jeff Mincy. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * cl-seq.el: Move the heavy lifting from this file to C. Dump the cl-parsing-keywords macro, but don't use defun* for the functions we define that do take keywords, dynamic scope lossage makes that not practical. * subr.el (sort, fillarray): Move these aliases here. (map-plist): #'nsublis is now built-in, but at this point #'eql isn't necessarily available as a test; use #'eq. * obsolete.el (cl-delete-duplicates): Make this available for old compiler macros and old code. (memql): Document that this is equivalent to #'member*, and worse. * cl.el (adjoin, subst): Removed. These are in C. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * simple.el (assoc-ignore-case): Remove a duplicate definition of this function (it's already in subr.el). * iso8859-1.el (char-width): On non-Mule, make this function equivalent to that produced by (constantly 1), but preserve its docstring. * subr.el (subst-char-in-string): Define this in terms of #'substitute, #'nsubstitute. (string-width): Define this using #'reduce and #'char-width. (char-width): Give this a simpler definition, it makes far more sense to check for mule at load time and redefine, as we do in iso8859-1.el. (store-substring): Implement this in terms of #'replace, now #'replace is cheap. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * update-elc.el (lisp-files-needed-for-byte-compilation) (lisp-files-needing-early-byte-compilation): cl-macs belongs in the former, not the latter, it is as fundamental as bytecomp.el. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * cl.el: Provde the Common Lisp program-error, type-error as error symbols. This doesn't nearly go far enough for anyone using the Common Lisp errors. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (delete-duplicates): If the form has an incorrect number of arguments, don't attempt a compiler macroexpansion. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (cl-safe-expr-p): Forms that start with the symbol lambda are also safe. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (= < > <= >=): For these functions' compiler macros, the optimisation is safe even if the first and the last arguments have side effects, since they're only used the once. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (inline-side-effect-free-compiler-macros): Unroll a loop here at macro-expansion time, so these compiler macros are compiled. Use #'eql instead of #'eq in a couple of places for better style. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-extra.el (notany, notevery): Avoid some dynamic scope stupidity with local variable names in these functions, when they weren't prefixed with cl-; go into some more detail in the doc strings. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (side-effect-free-fns): #'remove, #'remq are free of side-effects. (side-effect-and-error-free-fns): Drop dot, dot-marker from the list. 2010-11-17 Aidan Kehoe <kehoea@parhasard.net> * cl-extra.el (coerce): In the argument list, name the first argument OBJECT, not X; the former name was always used in the doc string and is clearer. Handle vector type specifications which include the length of the target sequence, error if there's a mismatch. * cl-macs.el (cl-make-type-test): Handle type specifications starting with the symbol 'eql. 2010-11-14 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (eql): Don't remove the byte-compile property of this symbol. That was necessary to override a bug in bytecomp.el where #'eql was confused with #'eq, which bug we no longer have. If neither expression is constant, don't attempt to handle the expression in this compiler macro, leave it to byte-compile-eql, which produces better code anyway. * bytecomp.el (eq): #'eql is not the function associated with the byte-eq byte code. (byte-compile-eql): Add an explicit compile method for this function, for cases where the cl-macs compiler macro hasn't reduced it to #'eq or #'equal. 2010-10-25 Aidan Kehoe <kehoea@parhasard.net> Add compiler macros and compilation sanity-checking for various functions that take keywords. * byte-optimize.el (side-effect-free-fns): #'symbol-value is side-effect free and not error free. * bytecomp.el (byte-compile-normal-call): Check keyword argument lists for sanity; store information about the positions where keyword arguments start using the new byte-compile-keyword-start property. * cl-macs.el (cl-const-expr-val): Take a new optional argument, cl-not-constant, defaulting to nil, in this function; return it if the expression is not constant. (cl-non-fixnum-number-p): Make this into a separate function, we want to pass it to #'every. (eql): Use it. (define-star-compiler-macros): Use the same code to generate the member*, assoc* and rassoc* compiler macros; special-case some code in #'add-to-list in subr.el. (remove, remq): Add compiler macros for these two functions, in preparation for #'remove being in C. (define-foo-if-compiler-macros): Transform (remove-if-not ...) calls to (remove ... :if-not) at compile time, which will be a real win once the latter is in C. (define-substitute-if-compiler-macros) (define-subst-if-compiler-macros): Similarly for these functions. (delete-duplicates): Change this compiler macro to use #'plists-equal; if we don't have information about the type of SEQUENCE at compile time, don't bother attempting to inline the call, the function will be in C soon enough. (equalp): Remove an old commented-out compiler macro for this, if we want to see it it's in version control. (subst-char-in-string): Transform this to a call to nsubstitute or nsubstitute, if that is appropriate. * cl.el (ldiff): Don't call setf here, this makes for a load-time dependency problem in cl-macs.el 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * term/vt100.el: Refer to XEmacs, not GNU Emacs, in permissions. * term/bg-mouse.el: * term/sup-mouse.el: Put copyright notice in canonical "Copyright DATE AUTHOR" form. Refer to XEmacs, not GNU Emacs, in permissions. * site-load.el: Add permission boilerplate. * mule/canna-leim.el: * alist.el: Refer to XEmacs, not APEL/this program, in permissions. * mule/canna-leim.el: Remove my copyright, I've assigned it to the FSF. 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * gtk.el: * gtk-widget-accessors.el: * gtk-package.el: * gtk-marshal.el: * gtk-compose.el: * gnome.el: Add copyright notice based on internal evidence. 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * easymenu.el: Add reference to COPYING to permission notice. * gutter.el: * gutter-items.el: * menubar-items.el: Fix typo "Xmacs" in permissions notice. 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * auto-save.el: * font.el: * fontconfig.el: * mule/kinsoku.el: Add "part of XEmacs" text to permission notice. 2010-10-14 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (side-effect-free-fns): * cl-macs.el (remf, getf): * cl-extra.el (tailp, cl-set-getf, cl-do-remf): * cl.el (ldiff, endp): Tighten up Common Lisp compatibility for #'ldiff, #'endp, #'tailp; add circularity checking for the first two. #'cl-set-getf and #'cl-do-remf were Lisp implementations of #'plist-put and #'plist-remprop; change the names to aliases, changes the macros that use them to using #'plist-put and #'plist-remprop directly. 2010-10-12 Aidan Kehoe <kehoea@parhasard.net> * abbrev.el (fundamental-mode-abbrev-table, global-abbrev-table): Create both these abbrev tables using the usual #'define-abbrev-table calls, rather than attempting to special-case them. * cl-extra.el: Force cl-macs to be loaded here, if cl-extra.el is being loaded interpreted. Previously other, later files would redundantly call (load "cl-macs") when interpreted, it's more reasonable to do it here, once. * cmdloop.el (read-quoted-char-radix): Use defcustom here, we don't have any dump-order dependencies that would prevent that. * custom.el (eval-when-compile): Don't load cl-macs when interpreted or when byte-compiling, rely on cl-extra.el in the former case and the appropriate entry in bytecomp-load-hook in the latter. Get rid of custom-declare-variable-list, we have no dump-time dependencies that would require it. * faces.el (eval-when-compile): Don't load cl-macs when interpreted or when byte-compiling. * packages.el: Remove some inaccurate comments. * post-gc.el (cleanup-simple-finalizers): Use #'delete-if-not here, now the order of preloaded-file-list has been changed to make it available. * subr.el (custom-declare-variable-list): Remove. No need for it. Also remove a stub define-abbrev-table from this file, given the current order of preloaded-file-list there's no need for it. 2010-10-10 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-constp) Forms quoted with FUNCTION are also constant. (byte-compile-initial-macro-environment): In #'the, if FORM is constant and does not match TYPE, warn at byte-compile time. 2010-10-10 Aidan Kehoe <kehoea@parhasard.net> * backquote.el (bq-vector-contents, bq-list*): Remove; the former is equivalent to (append VECTOR nil), the latter to (list* ...). (bq-process-2): Use (append VECTOR nil) instead of using #'bq-vector-contents to convert to a list. (bq-process-1): Now we use list* instead of bq-list * subr.el (list*): Moved from cl.el, since it is now required to be available the first time a backquoted form is encountered. * cl.el (list*): Move to subr.el. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * test-harness.el (Check-Message): Add an omitted comma here, thank you the buildbot. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * hash-table.el (hash-table-key-list, hash-table-value-list) (hash-table-key-value-alist, hash-table-key-value-plist): Remove some useless #'nreverse calls in these files; our hash tables have no order, it's not helpful to pretend they do. * behavior.el (read-behavior): Do the same in this file, in some code evidently copied from hash-table.el. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * info.el (Info-insert-dir): * format.el (format-deannotate-region): * files.el (cd, save-buffers-kill-emacs): Use #'some, #'every and related functions for applying boolean operations to lists, instead of rolling our own ones that cons and don't short-circuit. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-initial-macro-environment): * cl-macs.el (the): Rephrase the docstring, make its implementation when compiling files a little nicer. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * descr-text.el (unidata-initialize-unicodedata-database) (unidata-initialize-unihan-database, describe-char-unicode-data) (describe-char-unicode-data): Wrap calls to the database functions with (with-fboundp ...), avoiding byte compile warnings on builds without support for the database functions. (describe-char): (reduce #'max ...), not (apply #'max ...), no need to cons needlessly. (describe-char): Remove a redundant lambda wrapping #'extent-properties. (describe-char-unicode-data): Call #'nsubst when replacing "" with nil in the result of #'split-string, instead of consing inside mapcar. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * x-faces.el (x-available-font-sizes): * specifier.el (let-specifier): * package-ui.el (pui-add-required-packages): * msw-faces.el (mswindows-available-font-sizes): * modeline.el (modeline-minor-mode-menu): * minibuf.el (minibuf-directory-files): Replace the O2N (delq nil (mapcar (lambda (W) (and X Y)) Z)) with the ON (mapcan (lambda (W) (and X (list Y))) Z) in these files. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (= < > <= >=): When these functions are handed more than two arguments, and those arguments have no side effects, transform to a series of two argument calls, avoiding funcall in the byte-compiled code. * mule/mule-cmds.el (finish-set-language-environment): Take advantage of this change in a function called 256 times at startup. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-function-form, byte-compile-quote) (byte-compile-quote-form): Warn at compile time, and error at runtime, if a (quote ...) or a (function ...) form attempts to quote more than one object. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (byte-optimize-apply): Transform (apply 'nconc (mapcar ...)) to (mapcan ...); warn about use of the first idiom. * update-elc.el (do-autoload-commands): * packages.el (packages-find-package-library-path): * frame.el (frame-list): * extents.el (extent-descendants): * etags.el (buffer-tag-table-files): * dumped-lisp.el (preloaded-file-list): * device.el (device-list): * bytecomp-runtime.el (proclaim-inline, proclaim-notinline) Use #'mapcan, not (apply #'nconc (mapcar ...) in all these files. * bytecomp-runtime.el (eval-when-compile, eval-and-compile): In passing, mention that these macros also evaluate the body when interpreted. tests/ChangeLog addition: 2011-02-07 Aidan Kehoe <kehoea@parhasard.net> * automated/lisp-tests.el: Test lexical scope for `block', `return-from'; add a Known-Bug-Expect-Failure for a contorted example that fails when byte-compiled.
author Aidan Kehoe <kehoea@parhasard.net>
date Mon, 07 Feb 2011 12:01:24 +0000 (2011-02-07)
parents 33f0f28b945c
children 9fae6227ede5
line wrap: on
line source
@c -*-texinfo-*-
@c This is part of the XEmacs Lisp Reference Manual.
@c Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
@c See the file lispref.texi for copying conditions.
@setfilename ../../info/x-windows.texinfo
@node X-Windows, ToolTalk Support, System Interface, Top
@chapter Functions Specific to the X Window System
@cindex X
@cindex X-Windows

@c This section is largely different from the one in FSF Emacs.

XEmacs provides the concept of @dfn{devices}, which generalizes
connections to an X server, a TTY device, etc.  Most information about
an X server that XEmacs is connected to can be determined through
general console and device functions.  @xref{Consoles and Devices}.
However, there are some features of the X Window System that do not
generalize well, and they are covered specially here.

@menu
* X Selections::                Transferring text to and from other X clients.
* X Server::                    Information about the X server connected to
                                  a particular device.
* X Miscellaneous::             Other X-specific functions and variables.
@end menu

@node X Selections
@section X Selections
@cindex selection (for X windows)

The X server records a set of @dfn{selections} which permit transfer of
data between application programs.  The various selections are
distinguished by @dfn{selection types}, represented in XEmacs by
symbols.  X clients including XEmacs can read or set the selection for
any given type.

@defun x-own-selection data &optional type
This function sets a ``selection'' in the X server.  It takes two
arguments: a value, @var{data}, and the selection type @var{type} to
assign it to.  @var{data} may be a string, a cons of two markers, or an
extent.  In the latter cases, the selection is considered to be the text
between the markers, or between the extent's endpoints.

Each possible @var{type} has its own selection value, which changes
independently.  The usual values of @var{type} are @code{PRIMARY} and
@code{SECONDARY}; these are symbols with upper-case names, in accord
with X Windows conventions.  The default is @code{PRIMARY}.

(In FSF Emacs, this function is called @code{x-set-selection} and
takes different arguments.)
@end defun

@defun x-get-selection
This function accesses selections set up by XEmacs or by other X
clients.  It returns the value of the current primary selection.
@end defun

@defun x-disown-selection &optional secondary-p
Assuming we own the selection, this function disowns it.  If
@var{secondary-p} is non-@code{nil}, the secondary selection instead of
the primary selection is discarded.
@end defun

@cindex cut buffer
The X server also has a set of numbered @dfn{cut buffers} which can
store text or other data being moved between applications.  Cut buffers
are considered obsolete, but XEmacs supports them for the sake of X
clients that still use them.

@defun x-get-cutbuffer &optional n
This function returns the contents of cut buffer number @var{n}. (This
function is called @code{x-get-cut-buffer} in FSF Emacs.)
@end defun

@defun x-store-cutbuffer string &optional push
This function stores @var{string} into the first cut buffer (cut buffer
0).

Normally, the contents of the first cut buffer are simply replaced by
@var{string}.  However, if optional argument @var{push} is
non-@code{nil}, the cut buffers are rotated.  This means that the
previous value of the first cut buffer moves to the second cut buffer,
and the second to the third, and so on, moving the other values down
through the series of cut buffers, kill-ring-style.  There are 8 cut
buffers altogether.

Cut buffers are considered obsolete; you should use selections instead.

This function has no effect if support for cut buffers was not compiled in.

This function is called @code{x-set-cut-buffer} in FSF Emacs.
@end defun

@node X Server
@section X Server

This section describes how to access and change the overall status of
the X server XEmacs is using.

@menu
* Resources::                   Getting resource values from the server.
* Server Data::                 Getting info about the X server.
* Grabs::                       Restricting access to the server by other apps.
@end menu

@node Resources
@subsection Resources

@defun default-x-device
This function return the default X device for resourcing.  This is the
first-created X device that still exists.
@end defun

@defun x-get-resource name class type &optional locale device noerror
This function retrieves a resource value from the X resource manager.

@itemize @bullet
@item
The first arg is the name of the resource to retrieve, such as
@samp{"font"}.

@item
The second arg is the class of the resource to retrieve, like
@samp{"Font"}.

@item
The third arg should be one of the symbols @code{string},
@code{integer}, @code{natnum}, or @code{boolean}, specifying the type of
object that the database is searched for.

@item
The fourth arg is the locale to search for the resources on, and can
currently be a buffer, a frame, a device, or the symbol @code{global}.
If omitted, it defaults to @code{global}.

@item
The fifth arg is the device to search for the resources on. (The
resource database for a particular device is constructed by combining
non-device- specific resources such any command-line resources specified
and any app-defaults files found [or the fallback resources supplied by
XEmacs, if no app-defaults file is found] with device-specific resources
such as those supplied using @samp{xrdb}.) If omitted, it defaults to
the device of @var{locale}, if a device can be derived (i.e. if
@var{locale} is a frame or device), and otherwise defaults to the value
of @code{default-x-device}.

@item
The sixth arg @var{noerror}, if non-@code{nil}, means do not signal an
error if a bogus resource specification was retrieved (e.g. if a
non-integer was given when an integer was requested).  In this case, a
warning is issued instead.
@end itemize

The resource names passed to this function are looked up relative to the
locale.

If you want to search for a subresource, you just need to specify the
resource levels in @var{name} and @var{class}.  For example, @var{name}
could be @samp{"modeline.attributeFont"}, and @var{class}
@samp{"Face.AttributeFont"}.

Specifically,

@enumerate
@item
If @var{locale} is a buffer, a call

@example
    @code{(x-get-resource "foreground" "Foreground" 'string @var{some-buffer})}
@end example

is an interface to a C call something like

@example
    @code{XrmGetResource (db, "xemacs.buffer.@var{buffer-name}.foreground",
                        "Emacs.EmacsLocaleType.EmacsBuffer.Foreground",
                        "String");}
@end example

@item
If @var{locale} is a frame, a call

@example
    @code{(x-get-resource "foreground" "Foreground" 'string @var{some-frame})}
@end example

is an interface to a C call something like
@example

    @code{XrmGetResource (db, "xemacs.frame.@var{frame-name}.foreground",
                        "Emacs.EmacsLocaleType.EmacsFrame.Foreground",
                        "String");}
@end example

@item
If @var{locale} is a device, a call

@example
    @code{(x-get-resource "foreground" "Foreground" 'string @var{some-device})}
@end example

is an interface to a C call something like

@example
    @code{XrmGetResource (db, "xemacs.device.@var{device-name}.foreground",
                        "Emacs.EmacsLocaleType.EmacsDevice.Foreground",
                        "String");}
@end example

@item
If @var{locale} is the symbol @code{global}, a call

@example
    @code{(x-get-resource "foreground" "Foreground" 'string 'global)}
@end example

is an interface to a C call something like

@example
    @code{XrmGetResource (db, "xemacs.foreground",
                        "Emacs.Foreground",
                        "String");}
@end example
@end enumerate

Note that for @code{global}, no prefix is added other than that of the
application itself; thus, you can use this locale to retrieve arbitrary
application resources, if you really want to.

The returned value of this function is @code{nil} if the queried
resource is not found.  If @var{type} is @code{string}, a string is
returned, and if it is @code{integer}, an integer is returned.  If
@var{type} is @code{boolean}, then the returned value is the list
@code{(t)} for true, @code{(nil)} for false, and is @code{nil} to mean
``unspecified''.
@end defun

@defun x-put-resource resource-line &optional device
This function adds a resource to the resource database for @var{device}.
@var{resource-line} specifies the resource to add and should be a
standard resource specification.
@end defun

@defvar x-emacs-application-class
This variable holds The X application class of the XEmacs process.  This
controls, among other things, the name of the ``app-defaults'' file that
XEmacs will use.  For changes to this variable to take effect, they must
be made before the connection to the X server is initialized, that is,
this variable may only be changed before XEmacs is dumped, or by setting
it in the file @file{lisp/term/x-win.el}.

By default, this variable is @code{nil} at startup.  When the connection
to the X server is first initialized, the X resource database will
be consulted and the value will be set according to whether any
resources are found for the application class ``XEmacs''.
@end defvar

@node Server Data
@subsection Data about the X Server

  This section describes functions and a variable that you can use to
get information about the capabilities and origin of the X server
corresponding to a particular device.  The device argument is generally
optional and defaults to the selected device.

@defun x-server-version &optional device
This function returns the list of version numbers of the X server
@var{device} is on.  The returned value is a list of three integers: the
major and minor version numbers of the X protocol in use, and the
vendor-specific release number.
@end defun

@defun x-server-vendor &optional device
This function returns the vendor supporting the X server @var{device} is
on.
@end defun

@defun x-display-visual-class &optional device
This function returns the visual class of the display @var{device} is
on.  The value is one of the symbols @code{static-gray},
@code{gray-scale}, @code{static-color}, @code{pseudo-color},
@code{true-color}, and @code{direct-color}. (Note that this is different
from previous versions of XEmacs, which returned @code{StaticGray},
@code{GrayScale}, etc.)
@end defun

@node Grabs
@subsection Restricting Access to the Server by Other Apps

@defun x-grab-keyboard &optional device
This function grabs the keyboard on the given device (defaulting to the
selected one).  So long as the keyboard is grabbed, all keyboard events
will be delivered to XEmacs---it is not possible for other X clients to
eavesdrop on them.  Ungrab the keyboard with @code{x-ungrab-keyboard}
(use an @code{unwind-protect}).  Returns @code{t} if the grab was
successful; @code{nil} otherwise.
@end defun

@defun x-ungrab-keyboard &optional device
This function releases a keyboard grab made with @code{x-grab-keyboard}.
@end defun

@defun x-grab-pointer &optional device cursor ignore-keyboard
This function grabs the pointer and restricts it to its current window.
If optional @var{device} argument is @code{nil}, the selected device
will be used.  If optional @var{cursor} argument is non-@code{nil},
change the pointer shape to that until @code{x-ungrab-pointer} is called
(it should be an object returned by the @code{make-cursor} function).
If the second optional argument @var{ignore-keyboard} is non-@code{nil},
ignore all keyboard events during the grab.  Returns @code{t} if the
grab is successful, @code{nil} otherwise.
@end defun

@defun x-ungrab-pointer &optional device
This function releases a pointer grab made with @code{x-grab-pointer}.
If optional first arg @var{device} is @code{nil} the selected device is
used.  If it is @code{t} the pointer will be released on all X devices.
@end defun

@node X Miscellaneous
@section Miscellaneous X Functions and Variables

@defvar x-bitmap-file-path
This variable holds a list of the directories in which X bitmap files
may be found.  If @code{nil}, this is initialized from the
@samp{"*bitmapFilePath"} resource.  This is used by the
@code{make-image-instance} function (however, note that if the
environment variable @samp{XBMLANGPATH} is set, it is consulted first).
@end defvar

@defvar x-library-search-path
This variable holds the search path used by @code{read-color} to find
@file{rgb.txt}.
@end defvar

@defun x-valid-keysym-name-p keysym
This function returns true if @var{keysym} names a keysym that the X
library knows about.  Valid keysyms are listed in the files
@file{/usr/include/X11/keysymdef.h} and in
@file{/usr/lib/X11/XKeysymDB}, or whatever the equivalents are on your
system.
@end defun

@defun x-window-id &optional frame
This function returns the ID of the X11 window.  This gives us a chance
to manipulate the Emacs window from within a different program.  Since
the ID is an unsigned long, we return it as a string.
@end defun

@defvar x-allow-sendevents
If non-@code{nil}, synthetic events are allowed.  @code{nil} means
they are ignored.  Beware: allowing XEmacs to process SendEvents opens a
big security hole.
@end defvar

@defun x-debug-mode arg &optional device
With a true arg, make the connection to the X server synchronous.  With
false, make it asynchronous.  Synchronous connections are much slower,
but are useful for debugging. (If you get X errors, make the connection
synchronous, and use a debugger to set a breakpoint on
@code{x_error_handler}.  Your backtrace of the C stack will now be
useful.  In asynchronous mode, the stack above @code{x_error_handler}
isn't helpful because of buffering.)  If @var{device} is not specified,
the selected device is assumed.

Calling this function is the same as calling the C function
@code{XSynchronize}, or starting the program with the @samp{-sync}
command line argument.
@end defun

@defvar x-debug-events
If non-zero, debug information about events that XEmacs sees is
displayed.  Information is displayed on stderr.  Currently defined
values are:

@itemize @bullet
@item
1 == non-verbose output
@item
2 == verbose output
@end itemize
@end defvar