428
+ − 1 @c -*-texinfo-*-
+ − 2 @c This is part of the XEmacs Lisp Reference Manual.
444
+ − 3 @c Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
428
+ − 4 @c See the file lispref.texi for copying conditions.
+ − 5 @setfilename ../../info/building.info
+ − 6 @node Building XEmacs and Object Allocation, Standard Errors, Tips, Top
+ − 7 @appendix Building XEmacs; Allocation of Objects
+ − 8
+ − 9 This chapter describes how the runnable XEmacs executable is dumped
+ − 10 with the preloaded Lisp libraries in it and how storage is allocated.
+ − 11
+ − 12 There is an entire separate document, the @cite{XEmacs Internals
+ − 13 Manual}, devoted to the internals of XEmacs from the perspective of the
+ − 14 C programmer. It contains much more detailed information about the
+ − 15 build process, the allocation and garbage-collection process, and other
+ − 16 aspects related to the internals of XEmacs.
+ − 17
+ − 18 @menu
+ − 19 * Building XEmacs:: How to preload Lisp libraries into XEmacs.
+ − 20 * Pure Storage:: A kludge to make preloaded Lisp functions sharable.
+ − 21 * Garbage Collection:: Reclaiming space for Lisp objects no longer used.
+ − 22 @end menu
+ − 23
+ − 24 @node Building XEmacs
+ − 25 @appendixsec Building XEmacs
+ − 26 @cindex building XEmacs
+ − 27 @pindex temacs
+ − 28
+ − 29 This section explains the steps involved in building the XEmacs
+ − 30 executable. You don't have to know this material to build and install
+ − 31 XEmacs, since the makefiles do all these things automatically. This
+ − 32 information is pertinent to XEmacs maintenance.
+ − 33
+ − 34 The @cite{XEmacs Internals Manual} contains more information about this.
+ − 35
+ − 36 Compilation of the C source files in the @file{src} directory
+ − 37 produces an executable file called @file{temacs}, also called a
+ − 38 @dfn{bare impure XEmacs}. It contains the XEmacs Lisp interpreter and I/O
+ − 39 routines, but not the editing commands.
+ − 40
+ − 41 @cindex @file{loadup.el}
+ − 42 Before XEmacs is actually usable, a number of Lisp files need to be
+ − 43 loaded. These define all the editing commands, plus most of the startup
+ − 44 code and many very basic Lisp primitives. This is accomplished by
+ − 45 loading the file @file{loadup.el}, which in turn loads all of the other
+ − 46 standardly-loaded Lisp files.
+ − 47
+ − 48 It takes a substantial time to load the standard Lisp files. Luckily,
+ − 49 you don't have to do this each time you run XEmacs; @file{temacs} can
+ − 50 dump out an executable program called @file{xemacs} that has these files
+ − 51 preloaded. @file{xemacs} starts more quickly because it does not need to
+ − 52 load the files. This is the XEmacs executable that is normally
+ − 53 installed.
+ − 54
+ − 55 To create @file{xemacs}, use the command @samp{temacs -batch -l loadup
+ − 56 dump}. The purpose of @samp{-batch} here is to tell @file{temacs} to run
+ − 57 in non-interactive, command-line mode. (@file{temacs} can @emph{only} run
+ − 58 in this fashion. Part of the code required to initialize frames and faces
+ − 59 is in Lisp, and must be loaded before XEmacs is able to create any frames.)
+ − 60 The argument @samp{dump} tells @file{loadup.el} to dump a new executable
+ − 61 named @file{xemacs}.
+ − 62
+ − 63 The dumping process is highly system-specific, and some operating
+ − 64 systems don't support dumping. On those systems, you must start XEmacs
+ − 65 with the @samp{temacs -batch -l loadup run-temacs} command each time you
+ − 66 use it. This takes a substantial time, but since you need to start
+ − 67 Emacs once a day at most---or once a week if you never log out---the
+ − 68 extra time is not too severe a problem. (In older versions of Emacs,
+ − 69 you started Emacs from @file{temacs} using @samp{temacs -l loadup}.)
+ − 70
+ − 71 @cindex runnable @file{temacs}
+ − 72 @cindex bootstrapping XEmacs from @file{temacs}
+ − 73 You are free to start XEmacs directly from @file{temacs} if you want,
+ − 74 even if there is already a dumped @file{xemacs}. Normally you wouldn't
+ − 75 want to do that; but the Makefiles do this when you rebuild XEmacs using
+ − 76 @samp{make all-elc}, which builds XEmacs and simultaneously compiles any
+ − 77 out-of-date Lisp files. (You need @file{xemacs} in order to compile Lisp
+ − 78 files. However, you also need the compiled Lisp files in order to dump
+ − 79 out @file{xemacs}. If both of these are missing or corrupted, you are
+ − 80 out of luck unless you're able to bootstrap @file{xemacs} from
+ − 81 @file{temacs}. Note that @samp{make all-elc} actually loads the
+ − 82 alternative loadup file @file{loadup-el.el}, which works like
+ − 83 @file{loadup.el} but disables the pure-copying process and forces
+ − 84 XEmacs to ignore any compiled Lisp files even if they exist.)
+ − 85
+ − 86 @cindex @file{site-load.el}
+ − 87 You can specify additional files to preload by writing a library named
+ − 88 @file{site-load.el} that loads them. You may need to increase the value
+ − 89 of @code{PURESIZE}, in @file{src/puresize.h}, to make room for the
+ − 90 additional files. You should @emph{not} modify this file directly,
+ − 91 however; instead, use the @samp{--puresize} configuration option. (If
+ − 92 you run out of pure space while dumping @file{xemacs}, you will be told
+ − 93 how much pure space you actually will need.) However, the advantage of
+ − 94 preloading additional files decreases as machines get faster. On modern
+ − 95 machines, it is often not advisable, especially if the Lisp code is
+ − 96 on a file system local to the machine running XEmacs.
+ − 97
+ − 98 @cindex @file{site-init.el}
+ − 99 You can specify other Lisp expressions to execute just before dumping
+ − 100 by putting them in a library named @file{site-init.el}. However, if
+ − 101 they might alter the behavior that users expect from an ordinary
+ − 102 unmodified XEmacs, it is better to put them in @file{default.el}, so that
+ − 103 users can override them if they wish. @xref{Start-up Summary}.
+ − 104
+ − 105 Before @file{loadup.el} dumps the new executable, it finds the
+ − 106 documentation strings for primitive and preloaded functions (and
+ − 107 variables) in the file where they are stored, by calling
+ − 108 @code{Snarf-documentation} (@pxref{Accessing Documentation}). These
+ − 109 strings were moved out of the @file{xemacs} executable to make it
+ − 110 smaller. @xref{Documentation Basics}.
+ − 111
+ − 112 @defun dump-emacs to-file from-file
+ − 113 @cindex unexec
+ − 114 This function dumps the current state of XEmacs into an executable file
+ − 115 @var{to-file}. It takes symbols from @var{from-file} (this is normally
+ − 116 the executable file @file{temacs}).
+ − 117
+ − 118 If you use this function in an XEmacs that was already dumped, you must
+ − 119 set @code{command-line-processed} to @code{nil} first for good results.
+ − 120 @xref{Command Line Arguments}.
+ − 121 @end defun
+ − 122
+ − 123 @defun run-emacs-from-temacs &rest args
+ − 124 This is the function that implements the @file{run-temacs} command-line
+ − 125 argument. It is called from @file{loadup.el} as appropriate. You should
+ − 126 most emphatically @emph{not} call this yourself; it will reinitialize
+ − 127 your XEmacs process and you'll be sorry.
+ − 128 @end defun
+ − 129
444
+ − 130 @deffn Command emacs-version &optional arg
428
+ − 131 This function returns a string describing the version of XEmacs that is
+ − 132 running. It is useful to include this string in bug reports.
+ − 133
444
+ − 134 When called interactively with a prefix argument, insert string at point.
+ − 135 Don't use this function in programs to choose actions according
+ − 136 to the system configuration; look at @code{system-configuration} instead.
+ − 137
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+ − 138 @example
+ − 139 @group
+ − 140 (emacs-version)
+ − 141 @result{} "XEmacs 20.1 [Lucid] (i586-unknown-linux2.0.29)
+ − 142 of Mon Apr 7 1997 on altair.xemacs.org"
+ − 143 @end group
+ − 144 @end example
+ − 145
+ − 146 Called interactively, the function prints the same information in the
+ − 147 echo area.
+ − 148 @end deffn
+ − 149
+ − 150 @defvar emacs-build-time
+ − 151 The value of this variable is the time at which XEmacs was built at the
+ − 152 local site.
+ − 153
+ − 154 @example
+ − 155 @group
+ − 156 emacs-build-time "Mon Apr 7 20:28:52 1997"
444
+ − 157 @result{}
428
+ − 158 @end group
+ − 159 @end example
+ − 160 @end defvar
+ − 161
+ − 162 @defvar emacs-version
+ − 163 The value of this variable is the version of Emacs being run. It is a
+ − 164 string, e.g. @code{"20.1 XEmacs Lucid"}.
+ − 165 @end defvar
+ − 166
+ − 167 The following two variables did not exist before FSF GNU Emacs version
+ − 168 19.23 and XEmacs version 19.10, which reduces their usefulness at
+ − 169 present, but we hope they will be convenient in the future.
+ − 170
+ − 171 @defvar emacs-major-version
+ − 172 The major version number of Emacs, as an integer. For XEmacs version
+ − 173 20.1, the value is 20.
+ − 174 @end defvar
+ − 175
+ − 176 @defvar emacs-minor-version
+ − 177 The minor version number of Emacs, as an integer. For XEmacs version
+ − 178 20.1, the value is 1.
+ − 179 @end defvar
+ − 180
+ − 181 @node Pure Storage
+ − 182 @appendixsec Pure Storage
+ − 183 @cindex pure storage
+ − 184
+ − 185 XEmacs Lisp uses two kinds of storage for user-created Lisp objects:
+ − 186 @dfn{normal storage} and @dfn{pure storage}. Normal storage is where
+ − 187 all the new data created during an XEmacs session is kept; see the
+ − 188 following section for information on normal storage. Pure storage is
+ − 189 used for certain data in the preloaded standard Lisp files---data that
+ − 190 should never change during actual use of XEmacs.
+ − 191
+ − 192 Pure storage is allocated only while @file{temacs} is loading the
+ − 193 standard preloaded Lisp libraries. In the file @file{xemacs}, it is
+ − 194 marked as read-only (on operating systems that permit this), so that the
+ − 195 memory space can be shared by all the XEmacs jobs running on the machine
+ − 196 at once. Pure storage is not expandable; a fixed amount is allocated
+ − 197 when XEmacs is compiled, and if that is not sufficient for the preloaded
+ − 198 libraries, @file{temacs} aborts with an error message. If that happens,
+ − 199 you must increase the compilation parameter @code{PURESIZE} using the
+ − 200 @samp{--puresize} option to @file{configure}. This normally won't
+ − 201 happen unless you try to preload additional libraries or add features to
+ − 202 the standard ones.
+ − 203
+ − 204 @defun purecopy object
+ − 205 This function makes a copy of @var{object} in pure storage and returns
+ − 206 it. It copies strings by simply making a new string with the same
+ − 207 characters in pure storage. It recursively copies the contents of
+ − 208 vectors and cons cells. It does not make copies of other objects such
+ − 209 as symbols, but just returns them unchanged. It signals an error if
+ − 210 asked to copy markers.
+ − 211
+ − 212 This function is a no-op except while XEmacs is being built and dumped;
+ − 213 it is usually called only in the file
+ − 214 @file{xemacs/lisp/prim/loaddefs.el}, but a few packages call it just in
+ − 215 case you decide to preload them.
+ − 216 @end defun
+ − 217
+ − 218 @defvar pure-bytes-used
+ − 219 The value of this variable is the number of bytes of pure storage
+ − 220 allocated so far. Typically, in a dumped XEmacs, this number is very
+ − 221 close to the total amount of pure storage available---if it were not,
+ − 222 we would preallocate less.
+ − 223 @end defvar
+ − 224
+ − 225 @defvar purify-flag
+ − 226 This variable determines whether @code{defun} should make a copy of the
+ − 227 function definition in pure storage. If it is non-@code{nil}, then the
+ − 228 function definition is copied into pure storage.
+ − 229
+ − 230 This flag is @code{t} while loading all of the basic functions for
+ − 231 building XEmacs initially (allowing those functions to be sharable and
+ − 232 non-collectible). Dumping XEmacs as an executable always writes
+ − 233 @code{nil} in this variable, regardless of the value it actually has
+ − 234 before and after dumping.
+ − 235
+ − 236 You should not change this flag in a running XEmacs.
+ − 237 @end defvar
+ − 238
+ − 239 @node Garbage Collection
+ − 240 @appendixsec Garbage Collection
+ − 241 @cindex garbage collector
+ − 242
+ − 243 @cindex memory allocation
+ − 244 When a program creates a list or the user defines a new function (such
+ − 245 as by loading a library), that data is placed in normal storage. If
+ − 246 normal storage runs low, then XEmacs asks the operating system to
+ − 247 allocate more memory in blocks of 2k bytes. Each block is used for one
+ − 248 type of Lisp object, so symbols, cons cells, markers, etc., are
+ − 249 segregated in distinct blocks in memory. (Vectors, long strings,
+ − 250 buffers and certain other editing types, which are fairly large, are
+ − 251 allocated in individual blocks, one per object, while small strings are
+ − 252 packed into blocks of 8k bytes. [More correctly, a string is allocated
+ − 253 in two sections: a fixed size chunk containing the length, list of
+ − 254 extents, etc.; and a chunk containing the actual characters in the
+ − 255 string. It is this latter chunk that is either allocated individually
+ − 256 or packed into 8k blocks. The fixed size chunk is packed into 2k
+ − 257 blocks, as for conses, markers, etc.])
+ − 258
+ − 259 It is quite common to use some storage for a while, then release it by
+ − 260 (for example) killing a buffer or deleting the last pointer to an
+ − 261 object. XEmacs provides a @dfn{garbage collector} to reclaim this
+ − 262 abandoned storage. (This name is traditional, but ``garbage recycler''
+ − 263 might be a more intuitive metaphor for this facility.)
+ − 264
+ − 265 The garbage collector operates by finding and marking all Lisp objects
+ − 266 that are still accessible to Lisp programs. To begin with, it assumes
+ − 267 all the symbols, their values and associated function definitions, and
+ − 268 any data presently on the stack, are accessible. Any objects that can
+ − 269 be reached indirectly through other accessible objects are also
+ − 270 accessible.
+ − 271
+ − 272 When marking is finished, all objects still unmarked are garbage. No
+ − 273 matter what the Lisp program or the user does, it is impossible to refer
+ − 274 to them, since there is no longer a way to reach them. Their space
+ − 275 might as well be reused, since no one will miss them. The second
+ − 276 (``sweep'') phase of the garbage collector arranges to reuse them.
+ − 277
+ − 278 @cindex free list
+ − 279 The sweep phase puts unused cons cells onto a @dfn{free list} for
+ − 280 future allocation; likewise for symbols, markers, extents, events,
+ − 281 floats, compiled-function objects, and the fixed-size portion of
+ − 282 strings. It compacts the accessible small string-chars chunks so they
+ − 283 occupy fewer 8k blocks; then it frees the other 8k blocks. Vectors,
+ − 284 buffers, windows, and other large objects are individually allocated and
+ − 285 freed using @code{malloc} and @code{free}.
+ − 286
+ − 287 @cindex CL note---allocate more storage
+ − 288 @quotation
+ − 289 @b{Common Lisp note:} unlike other Lisps, XEmacs Lisp does not
+ − 290 call the garbage collector when the free list is empty. Instead, it
+ − 291 simply requests the operating system to allocate more storage, and
+ − 292 processing continues until @code{gc-cons-threshold} bytes have been
+ − 293 used.
+ − 294
+ − 295 This means that you can make sure that the garbage collector will not
+ − 296 run during a certain portion of a Lisp program by calling the garbage
+ − 297 collector explicitly just before it (provided that portion of the
+ − 298 program does not use so much space as to force a second garbage
+ − 299 collection).
+ − 300 @end quotation
+ − 301
+ − 302 @deffn Command garbage-collect
+ − 303 This command runs a garbage collection, and returns information on
+ − 304 the amount of space in use. (Garbage collection can also occur
+ − 305 spontaneously if you use more than @code{gc-cons-threshold} bytes of
+ − 306 Lisp data since the previous garbage collection.)
+ − 307
+ − 308 @code{garbage-collect} returns a list containing the following
+ − 309 information:
+ − 310
+ − 311 @example
+ − 312 @group
+ − 313 ((@var{used-conses} . @var{free-conses})
+ − 314 (@var{used-syms} . @var{free-syms})
+ − 315 @end group
+ − 316 (@var{used-markers} . @var{free-markers})
444
+ − 317 @var{used-string-chars}
428
+ − 318 @var{used-vector-slots}
+ − 319 (@var{plist}))
+ − 320
+ − 321 @group
+ − 322 @result{} ((73362 . 8325) (13718 . 164)
+ − 323 (5089 . 5098) 949121 118677
+ − 324 (conses-used 73362 conses-free 8329 cons-storage 658168
+ − 325 symbols-used 13718 symbols-free 164 symbol-storage 335216
+ − 326 bit-vectors-used 0 bit-vectors-total-length 0
+ − 327 bit-vector-storage 0 vectors-used 7882
+ − 328 vectors-total-length 118677 vector-storage 537764
+ − 329 compiled-functions-used 1336 compiled-functions-free 37
+ − 330 compiled-function-storage 44440 short-strings-used 28829
+ − 331 long-strings-used 2 strings-free 7722
+ − 332 short-strings-total-length 916657 short-string-storage 1179648
+ − 333 long-strings-total-length 32464 string-header-storage 441504
+ − 334 floats-used 3 floats-free 43 float-storage 2044 markers-used 5089
+ − 335 markers-free 5098 marker-storage 245280 events-used 103
+ − 336 events-free 835 event-storage 110656 extents-used 10519
+ − 337 extents-free 2718 extent-storage 372736
+ − 338 extent-auxiliarys-used 111 extent-auxiliarys-freed 3
+ − 339 extent-auxiliary-storage 4440 window-configurations-used 39
+ − 340 window-configurations-on-free-list 5
+ − 341 window-configurations-freed 10 window-configuration-storage 9492
+ − 342 popup-datas-used 3 popup-data-storage 72 toolbar-buttons-used 62
+ − 343 toolbar-button-storage 4960 toolbar-datas-used 12
+ − 344 toolbar-data-storage 240 symbol-value-buffer-locals-used 182
+ − 345 symbol-value-buffer-local-storage 5824
+ − 346 symbol-value-lisp-magics-used 22
+ − 347 symbol-value-lisp-magic-storage 1496
+ − 348 symbol-value-varaliases-used 43
+ − 349 symbol-value-varalias-storage 1032 opaque-lists-used 2
+ − 350 opaque-list-storage 48 color-instances-used 12
+ − 351 color-instance-storage 288 font-instances-used 5
+ − 352 font-instance-storage 180 opaques-used 11 opaque-storage 312
+ − 353 range-tables-used 1 range-table-storage 16 faces-used 34
+ − 354 face-storage 2584 glyphs-used 124 glyph-storage 4464
+ − 355 specifiers-used 775 specifier-storage 43869 weak-lists-used 786
+ − 356 weak-list-storage 18864 char-tables-used 40
+ − 357 char-table-storage 41920 buffers-used 25 buffer-storage 7000
+ − 358 extent-infos-used 457 extent-infos-freed 73
+ − 359 extent-info-storage 9140 keymaps-used 275 keymap-storage 12100
+ − 360 consoles-used 4 console-storage 384 command-builders-used 2
+ − 361 command-builder-storage 120 devices-used 2 device-storage 344
+ − 362 frames-used 3 frame-storage 624 image-instances-used 47
+ − 363 image-instance-storage 3008 windows-used 27 windows-freed 2
+ − 364 window-storage 9180 lcrecord-lists-used 15
+ − 365 lcrecord-list-storage 360 hash-tables-used 631
+ − 366 hash-table-storage 25240 streams-used 1 streams-on-free-list 3
+ − 367 streams-freed 12 stream-storage 91))
+ − 368 @end group
+ − 369 @end example
+ − 370
+ − 371 Here is a table explaining each element:
+ − 372
+ − 373 @table @var
+ − 374 @item used-conses
+ − 375 The number of cons cells in use.
+ − 376
+ − 377 @item free-conses
+ − 378 The number of cons cells for which space has been obtained from the
+ − 379 operating system, but that are not currently being used.
+ − 380
+ − 381 @item used-syms
+ − 382 The number of symbols in use.
+ − 383
+ − 384 @item free-syms
+ − 385 The number of symbols for which space has been obtained from the
+ − 386 operating system, but that are not currently being used.
+ − 387
+ − 388 @item used-markers
+ − 389 The number of markers in use.
+ − 390
+ − 391 @item free-markers
+ − 392 The number of markers for which space has been obtained from the
+ − 393 operating system, but that are not currently being used.
+ − 394
+ − 395 @item used-string-chars
+ − 396 The total size of all strings, in characters.
+ − 397
+ − 398 @item used-vector-slots
+ − 399 The total number of elements of existing vectors.
+ − 400
+ − 401 @item plist
+ − 402 A list of alternating keyword/value pairs providing more detailed
+ − 403 information. (As you can see above, quite a lot of information is
+ − 404 provided.)
+ − 405 @ignore @c Different in XEmacs
+ − 406
+ − 407 @item used-floats
+ − 408 @c Emacs 19 feature
+ − 409 The number of floats in use.
+ − 410
+ − 411 @item free-floats
+ − 412 @c Emacs 19 feature
+ − 413 The number of floats for which space has been obtained from the
+ − 414 operating system, but that are not currently being used.
+ − 415 @end ignore
+ − 416 @end table
+ − 417 @end deffn
+ − 418
+ − 419 @defopt gc-cons-threshold
+ − 420 The value of this variable is the number of bytes of storage that must
+ − 421 be allocated for Lisp objects after one garbage collection in order to
+ − 422 trigger another garbage collection. A cons cell counts as eight bytes,
+ − 423 a string as one byte per character plus a few bytes of overhead, and so
+ − 424 on; space allocated to the contents of buffers does not count. Note
+ − 425 that the subsequent garbage collection does not happen immediately when
+ − 426 the threshold is exhausted, but only the next time the Lisp evaluator is
+ − 427 called.
+ − 428
+ − 429 The initial threshold value is 500,000. If you specify a larger
+ − 430 value, garbage collection will happen less often. This reduces the
+ − 431 amount of time spent garbage collecting, but increases total memory use.
+ − 432 You may want to do this when running a program that creates lots of
+ − 433 Lisp data.
+ − 434
+ − 435 You can make collections more frequent by specifying a smaller value,
+ − 436 down to 10,000. A value less than 10,000 will remain in effect only
+ − 437 until the subsequent garbage collection, at which time
+ − 438 @code{garbage-collect} will set the threshold back to 10,000. (This does
+ − 439 not apply if XEmacs was configured with @samp{--debug}. Therefore, be
+ − 440 careful when setting @code{gc-cons-threshold} in that case!)
+ − 441 @end defopt
+ − 442
444
+ − 443 @ignore
428
+ − 444 @c Emacs 19 feature
+ − 445 @defun memory-limit
+ − 446 This function returns the address of the last byte XEmacs has allocated,
+ − 447 divided by 1024. We divide the value by 1024 to make sure it fits in a
+ − 448 Lisp integer.
+ − 449
+ − 450 You can use this to get a general idea of how your actions affect the
+ − 451 memory usage.
+ − 452 @end defun
444
+ − 453 @end ignore
428
+ − 454
+ − 455 @defvar pre-gc-hook
+ − 456 This is a normal hook to be run just before each garbage collection.
+ − 457 Interrupts, garbage collection, and errors are inhibited while this hook
+ − 458 runs, so be extremely careful in what you add here. In particular,
+ − 459 avoid consing, and do not interact with the user.
+ − 460 @end defvar
+ − 461
+ − 462 @defvar post-gc-hook
+ − 463 This is a normal hook to be run just after each garbage collection.
+ − 464 Interrupts, garbage collection, and errors are inhibited while this hook
+ − 465 runs, so be extremely careful in what you add here. In particular,
+ − 466 avoid consing, and do not interact with the user.
+ − 467 @end defvar
+ − 468
+ − 469 @defvar gc-message
+ − 470 This is a string to print to indicate that a garbage collection is in
+ − 471 progress. This is printed in the echo area. If the selected frame is
+ − 472 on a window system and @code{gc-pointer-glyph} specifies a value (i.e. a
+ − 473 pointer image instance) in the domain of the selected frame, the mouse
+ − 474 cursor will change instead of this message being printed.
+ − 475 @end defvar
+ − 476
+ − 477 @defvr Glyph gc-pointer-glyph
+ − 478 This holds the pointer glyph used to indicate that a garbage collection
+ − 479 is in progress. If the selected window is on a window system and this
+ − 480 glyph specifies a value (i.e. a pointer image instance) in the domain of
+ − 481 the selected window, the cursor will be changed as specified during
+ − 482 garbage collection. Otherwise, a message will be printed in the echo
+ − 483 area, as controlled by @code{gc-message}. @xref{Glyphs}.
+ − 484 @end defvr
+ − 485
+ − 486 If XEmacs was configured with @samp{--debug}, you can set the following
+ − 487 two variables to get direct information about all the allocation that
+ − 488 is happening in a segment of Lisp code.
+ − 489
+ − 490 @defvar debug-allocation
+ − 491 If non-zero, print out information to stderr about all objects
+ − 492 allocated.
+ − 493 @end defvar
+ − 494
+ − 495 @defvar debug-allocation-backtrace
+ − 496 Length (in stack frames) of short backtrace printed out by
+ − 497 @code{debug-allocation}.
+ − 498 @end defvar
