Merge from emacs-23
[bpt/emacs.git] / nt / INSTALL
1 Building and Installing Emacs on Windows
2 (from 95 to 7 and beyond)
3
4 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
5 Free Software Foundation, Inc.
6 See the end of the file for license conditions.
7
8 * For the impatient
9
10 Here are the concise instructions for configuring and building the
11 native Windows binary of Emacs, for those who want to skip the
12 complex explanations and ``just do it'':
13
14 Do not use this recipe with Cygwin. For building on Cygwin,
15 use the normal installation instructions, ../INSTALL.
16
17 1. Change to the `nt' directory (the directory of this file):
18
19 cd nt
20
21 2. Run configure.bat. From the COMMAND.COM/CMD.EXE command prompt:
22
23 configure
24
25 from a Unixy shell prompt:
26
27 cmd /c configure.bat
28 or
29 command.com /c configure.bat
30
31 3. Run the Make utility suitable for your environment. If you build
32 with the Microsoft's Visual C compiler (but see notes about using
33 VC++ 8.0 and later below):
34
35 nmake
36
37 For the development environments based on GNU GCC (MinGW, MSYS,
38 Cygwin - but see notes about Cygwin make below), depending on how
39 Make is called, it could be:
40
41 make
42 or
43 mingw32-make
44 or
45 gnumake
46 or
47 gmake
48
49 (If you are building from Bazaar, say "make bootstrap" or "nmake
50 bootstrap" instead, and avoid using Cygwin make.)
51
52 With GNU Make, you can use the -j command-line option to have
53 Make execute several commands at once, like this:
54
55 gmake -j 2 XMFLAGS="-j 2"
56
57 The XMFLAGS variable overrides the default behavior of GNU Make
58 on Windows, whereby recursive Make invocations reset the maximum
59 number of simultaneous commands to 1. The above command allows
60 up to 4 simultaneous commands at once in the top-level Make, and
61 up to 3 in each one of the recursive Make's.
62
63 4. Generate the Info manuals (only if you are building out of Bazaar,
64 and if you have makeinfo.exe installed):
65
66 make info
67
68 (change "make" to "nmake" if you use MSVC).
69
70 5. Install the produced binaries:
71
72 make install
73
74 That's it!
75
76 If these short instructions somehow fail, read the rest of this
77 file.
78
79 * Preliminaries
80
81 If you want to build a Cygwin port of Emacs, use the instructions in
82 the INSTALL file in the main Emacs directory (the parent of this
83 directory). These instructions are for building a native Windows
84 binary of Emacs.
85
86 If you used WinZip to unpack the distribution, we suggest to
87 remove the files and unpack again with a different program!
88 WinZip is known to create some subtle and hard to debug problems,
89 such as converting files to DOS CR-LF format, not creating empty
90 directories, etc. We suggest to use djtarnt.exe from the GNU FTP
91 site.
92
93 In addition to this file, you should also read INSTALL.BZR in the
94 parent directory, and make sure that you have a version of
95 "touch.exe" in your path, and that it will create files that do not
96 yet exist.
97
98 * Supported development environments
99
100 To compile Emacs, you will need either Microsoft Visual C++ 2.0, or
101 later up to 7.0, and nmake, or a Windows port of GCC 2.95 or later
102 with MinGW and W32 API support and a port of GNU Make. You can use
103 the Cygwin ports of GCC, but Emacs requires the MinGW headers and
104 libraries to build (latest versions of the Cygwin toolkit, at least
105 since v1.3.3, include the MinGW headers and libraries as an integral
106 part).
107
108 Note that building Emacs with Visual Studio 2005 (VC++ 8.0) and
109 later is not supported at this time, due to changes introduced by
110 Microsoft into the libraries shipped with the compiler.
111
112 The rest of this file assumes you have a working development
113 environment. If you just installed such an environment, try
114 building a trivial C "Hello world" program, and see if it works. If
115 it doesn't work, resolve that problem first! If you use Microsoft
116 Visual Studio .NET 2003, don't forget to run the VCVARS32.BAT batch
117 file from the `Bin' subdirectory of the directory where you have
118 installed VS.NET.
119
120 If you use the MinGW port of GCC and GNU Make to build Emacs, there
121 are some compatibility issues wrt Make and the shell that is run by
122 Make, either the standard COMMAND.COM/CMD.EXE supplied with Windows
123 or sh.exe, a port of a Unixy shell. For reference, below is a list
124 of which builds of GNU Make are known to work or not, and whether
125 they work in the presence and/or absence of sh.exe, the Cygwin port
126 of Bash. Note that any version of Make that is compiled with Cygwin
127 will only work with Cygwin tools, due to the use of Cygwin style
128 paths. This means Cygwin Make is unsuitable for building parts of
129 Emacs that need to invoke Emacs itself (leim and "make bootstrap",
130 for example). Also see the Trouble-shooting section below if you
131 decide to go ahead and use Cygwin make.
132
133 In addition, using 4NT or TCC as your shell is known to fail the build
134 process, at least since 4NT version 3.01. Use CMD.EXE, the default
135 Windows shell, instead. MSYS sh.exe also appears to cause various
136 problems. If you have MSYS installed, try "make SHELL=cmd.exe" to
137 force the use of cmd.exe instead of sh.exe.
138
139 sh exists no sh
140
141 cygwin b20.1 make (3.75): fails[1, 5] fails[2, 5]
142 MSVC compiled gmake 3.77: okay okay
143 MSVC compiled gmake 3.78.1: okay okay
144 MSVC compiled gmake 3.79.1: okay okay
145 mingw32/gcc-2.92.2 make (3.77): okay okay[4]
146 cygwin compiled gmake 3.77: fails[1, 5] fails[2, 5]
147 cygwin compiled make 3.78.1: fails[5] fails[2, 5]
148 cygwin compiled make 3.79.1: fails[3, 5] fails[2?, 5]
149 cygwin compiled make 3.80: okay[6] fails?[7]
150 cygwin compiled make 3.81: fails fails?[7]
151 mingw32 compiled make 3.79.1: okay okay
152 mingw32 compiled make 3.80: okay okay[7]
153 mingw32 compiled make 3.81: okay okay[8]
154
155 Notes:
156
157 [1] doesn't cope with makefiles with DOS line endings, so must mount
158 emacs source with text!=binary.
159 [2] fails when needs to invoke shell commands; okay invoking gcc etc.
160 [3] requires LC_MESSAGES support to build; cannot build with early
161 versions of Cygwin.
162 [4] may fail on Windows 9X and Windows ME; if so, install Bash.
163 [5] fails when building leim due to the use of cygwin style paths.
164 May work if building emacs without leim.
165 [6] need to uncomment 3 lines in nt/gmake.defs that invoke `cygpath'
166 (look for "cygpath" near line 85 of gmake.defs).
167 [7] not recommended; please report if you try this combination.
168 [8] tested only on Windows XP.
169
170 Other compilers may work, but specific reports from people that have
171 tried suggest that the Intel C compiler (for example) may produce an
172 Emacs executable with strange filename completion behavior. Unless
173 you would like to assist by finding and fixing the cause of any bugs
174 like this, we recommend the use of the supported compilers mentioned
175 in the previous paragraph.
176
177 You will also need a copy of the POSIX cp, rm and mv programs. These
178 and other useful POSIX utilities can be obtained from one of several
179 projects:
180
181 * http://gnuwin32.sourceforge.net/ ( GnuWin32 )
182 * http://www.mingw.org/ ( MinGW )
183 * http://www.cygwin.com/ ( Cygwin )
184 * http://unxutils.sourceforge.net/ ( UnxUtils )
185
186 If you build Emacs on 16-bit versions of Windows (9X or ME), we
187 suggest to install the Cygwin port of Bash. That is because the
188 native Windows shell COMMAND.COM is too limited; the Emacs build
189 procedure tries very hard to support even such limited shells, but
190 as none of the Windows developers of Emacs work on Windows 9X, we
191 cannot guarantee that it works without a more powerful shell.
192
193 Additional instructions and help for building Emacs on Windows can be
194 found at the Emacs Wiki:
195
196 http://www.emacswiki.org/cgi-bin/wiki/WThirtyTwoInstallationKit
197
198 and on these URLs:
199
200 http://ourcomments.org/Emacs/w32-build-emacs.html
201 http://derekslager.com/blog/posts/2007/01/emacs-hack-3-compile-emacs-from-cvs-on-windows.ashx
202
203 Both of those pages were written before Emacs switched from CVS to
204 Bazaar, but the parts about building Emacs still apply in Bazaar.
205 The second URL has instructions for building with MSVC, as well as
206 with MinGW, while the first URL covers only MinGW, but has more
207 details about it.
208
209 * Configuring
210
211 Configuration of Emacs is now handled by running configure.bat in the
212 `nt' subdirectory. It will detect which compiler you have available,
213 and generate makefiles accordingly. You can override the compiler
214 detection, and control optimization and debug settings, by specifying
215 options on the command line when invoking configure.
216
217 To configure Emacs to build with GCC or MSVC, whichever is available,
218 simply change to the `nt' subdirectory and run `configure.bat' with no
219 options. To see what options are available, run `configure --help'.
220 Do NOT use the --no-debug option to configure.bat unless you are
221 absolutely sure the produced binaries will never need to be run under
222 a debugger.
223
224 Because of limitations of the stock Windows command shell, certain
225 characters (quotes, backslashes and equal signs) can be problematic
226 and should not be used in arguments to configure. That means that
227 forward slashes must be used in paths passed to the compiler and
228 linker via the --cflags and --ldflags options, and that it is
229 currently not possible to pass a macro like -DFOO=BAR (though -DFOO
230 is perfectly valid).
231
232 N.B. It is normal to see a few error messages output while configure
233 is running, when gcc support is being tested. These cannot be
234 suppressed because of limitations in the Windows 9X command.com shell.
235
236 You are encouraged to look at the file config.log which shows details
237 for failed tests, after configure.bat finishes. Any unexplained failure
238 should be investigated and perhaps reported as a bug (see the section
239 about reporting bugs in the file README in this directory and in the
240 Emacs manual).
241
242 * Optional image library support
243
244 In addition to its "native" image formats (pbm and xbm), Emacs can
245 handle other image types: xpm, tiff, gif, png, jpeg and experimental
246 support for svg.
247
248 To build Emacs with support for them, the corresponding headers must
249 be in the include path when the configure script is run. This can
250 be setup using environment variables, or by specifying --cflags
251 -I... options on the command-line to configure.bat. The configure
252 script will report whether it was able to detect the headers. If
253 the results of this testing appear to be incorrect, please look for
254 details in the file config.log: it will show the failed test
255 programs and compiler error messages that should explain what is
256 wrong. (Usually, any such failures happen because some headers are
257 missing due to bad packaging of the image support libraries.)
258
259 Note that any file path passed to the compiler or linker must use
260 forward slashes; using backslashes will cause compiler warnings or
261 errors about unrecognized escape sequences.
262
263 To use the external image support, the DLLs implementing the
264 functionality must be found when Emacs first needs them, either on the
265 PATH, or in the same directory as emacs.exe. Failure to find a
266 library is not an error; the associated image format will simply be
267 unavailable. Note that once Emacs has determined that a library can
268 not be found, there's no way to force it to try again, other than
269 restarting. See the variable `dynamic-library-alist' to configure the
270 expected names of the libraries.
271
272 Some image libraries have dependencies on one another, or on zlib.
273 For example, tiff support depends on the jpeg library. If you did not
274 compile the libraries yourself, you must make sure that any dependency
275 is in the PATH or otherwise accessible and that the binaries are
276 compatible (for example, that they were built with the same compiler).
277
278 Binaries for the image libraries (among many others) can be found at
279 the GnuWin32 project. PNG, JPEG and TIFF libraries are also
280 included with GTK, which is installed along with other Free Software
281 that requires it. These are built with MinGW, but they can be used
282 with both GCC/MinGW and MSVC builds of Emacs. See the info on
283 http://ourcomments.org/Emacs/w32-build-emacs.html, under "How to Get
284 Images Support", for more details about installing image support
285 libraries. Note specifically that, due to some packaging snafus in
286 the GnuWin32-supplied image libraries, you will need to download
287 _source_ packages for some of the libraries in order to get the
288 header files necessary for building Emacs with image support.
289
290 If GTK 2.0 is installed, addpm will arrange for its image libraries
291 to be on the DLL search path for Emacs.
292
293 For PNG images, we recommend to use versions 1.4.x and later of
294 libpng, because previous versions had security issues. You can find
295 precompiled libraries and headers on the GTK download page for
296 Windows (http://www.gtk.org/download-windows.html).
297
298 Versions 1.4.0 and later of libpng are binary incompatible with
299 earlier versions, so Emacs will only look for libpng libraries which
300 are compatible with the version it was compiled against. That
301 version is given by the value of the Lisp variable `libpng-version';
302 e.g., 10403 means version 1.4.3. The variable `dynamic-library-alist'
303 is automatically set to name only those DLL names that are known to
304 be compatible with the version given by `libpng-version'. If PNG
305 support does not work for you even though you have the support DLL
306 installed, check the name of the installed DLL against
307 `dynamic-library-alist' and the value of `libpng-version', and
308 download compatible DLLs if needed.
309
310 * Experimental SVG support
311
312 SVG support is currently experimental, and not built by default.
313 Specify --with-svg and ensure you have all the dependencies in your
314 include path. Unless you have built a minimalist librsvg yourself
315 (untested), librsvg depends on a significant chunk of GTK+ to build,
316 plus a few Gnome libraries, libxml2, libbz2 and zlib at runtime. The
317 easiest way to obtain the dependencies required for building is to
318 download a pre-bundled GTK+ development environment for Windows.
319 GTK puts its header files all over the place, so you will need to
320 run pkgconfig to list the include path you will need (either passed
321 to configure.bat as --cflags options, or set in the environment).
322
323 To use librsvg at runtime, ensure that librsvg and its dependencies
324 are on your PATH. If you didn't build librsvg yourself, you will
325 need to check with where you downloaded it from for the
326 dependencies, as there are different build options. If it is a
327 short list, then it most likely only lists the immediate
328 dependencies of librsvg, but the dependencies themselves have
329 dependencies - so don't download individual libraries from GTK+,
330 download and install the whole thing. If you think you've got all
331 the dependencies and SVG support is still not working, check your
332 PATH for other libraries that shadow the ones you downloaded.
333 Libraries of the same name from different sources may not be
334 compatible, this problem was encountered with libbzip2 from GnuWin32
335 with libcroco from gnome.org.
336
337 If you can see etc/images/splash.svg, then you have managed to get
338 SVG support working. Congratulations for making it through DLL hell
339 to this point. You'll probably find that some SVG images crash
340 Emacs. Problems have been observed in some images that contain
341 text, they seem to be a problem in the Windows port of Pango, or
342 maybe a problem with the way Cairo or librsvg is using it that
343 doesn't show up on other platforms.
344
345 * Building
346
347 After running configure, simply run the appropriate `make' program for
348 your compiler to build Emacs. For MSVC, this is nmake; for GCC, it is
349 GNU make. (If you are building out of Bazaar, say "make bootstrap" or
350 "nmake bootstrap" instead.)
351
352 As the files are compiled, you will see some warning messages
353 declaring that some functions don't return a value, or that some data
354 conversions will be lossy, etc. You can safely ignore these messages.
355 The warnings may be fixed in the main FSF source at some point, but
356 until then we will just live with them.
357
358 With GNU Make, you can use the -j command-line option to have Make
359 execute several commands at once, like this:
360
361 gmake -j 4 XMFLAGS="-j 3"
362
363 The XMFLAGS variable overrides the default behavior of GNU Make on
364 Windows, whereby recursive Make invocations reset the maximum number
365 of simultaneous commands to 1. The above command allows up to 4
366 simultaneous commands at once in the top-level Make, and up to 3 in
367 each one of the recursive Make's; you can use other numbers of jobs,
368 if you wish.
369
370 If you are building from Bazaar, the following commands will produce
371 the Info manuals (which are not part of the Bazaar sources):
372
373 make info
374 or
375 nmake info
376
377 Note that you will need makeinfo.exe (from the GNU Texinfo package)
378 in order for this command to succeed.
379
380 * Installing
381
382 To install Emacs after it has compiled, simply run `nmake install'
383 or `make install', depending on which version of the Make utility
384 do you have.
385
386 By default, Emacs will be installed in the location where it was
387 built, but a different location can be specified either using the
388 --prefix option to configure, or by setting INSTALL_DIR when running
389 make, like so:
390
391 make install INSTALL_DIR=D:/emacs
392
393 (for `nmake', type "nmake install INSTALL_DIR=D:/emacs" instead).
394
395 The install process will run addpm to setup the registry entries, and
396 to create a Start menu icon for Emacs.
397
398 * Make targets
399
400 The following make targets may be used by users building the source
401 distribution, or users who have checked out of Bazaar after
402 an initial bootstrapping.
403
404 make
405 Builds Emacs from the available sources and pre-compiled lisp files.
406
407 make install
408 Installs programs to the bin directory, and runs addpm to create
409 Start Menu icons.
410
411 make clean
412 Removes object and executable files produced by the build process in
413 the current configuration. After make clean, you can rebuild with
414 the same configuration using make.
415
416 make distclean
417 In addition to the files removed by make clean, this also removes
418 Makefiles and other generated files to get back to the state of a
419 freshly unpacked source distribution. Note that this will not remove
420 installed files, or the results of builds performed with different
421 compiler or optimization options than the current configuration.
422 After make distclean, it is necessary to run configure.bat followed
423 by make to rebuild.
424
425 make cleanall
426 Removes object and executable files that may have been created by
427 previous builds with different configure options, in addition to
428 the files produced by the current configuration.
429
430 make realclean
431 Removes the installed files in the bin subdirectory in addition to
432 the files removed by make cleanall.
433
434 make dist
435 Builds Emacs from the available sources and pre-compiled lisp files.
436 Packages Emacs binaries as full distribution and barebin distribution.
437
438 The following targets are intended only for use with the Bazaar sources.
439
440 make bootstrap
441 Creates a temporary emacs binary with lisp source files and
442 uses it to compile the lisp files. Once the lisp files are built,
443 emacs is redumped with the compiled lisp.
444
445 make recompile
446 Recompiles any changed lisp files after an update. This saves
447 doing a full bootstrap after every update. If this or a subsequent
448 make fail, you probably need to perform a full bootstrap, though
449 running this target multiple times may eventually sort out the
450 interdependencies.
451
452 make maintainer-clean
453 Removes everything that can be recreated, including compiled lisp
454 files, to get back to the state of a fresh Bazaar tree. After make
455 maintainer-clean, it is necessary to run configure.bat and make
456 bootstrap to rebuild. Occasionally it may be necessary to run this
457 target after an update.
458
459 * Creating binary distributions
460
461 Binary distributions (full and barebin distributions) can be
462 automatically built and packaged from source tarballs or a bzr
463 checkout.
464
465 When building Emacs binary distributions, the --distfiles argument
466 to configure.bat specifies files to be included in the bin directory
467 of the binary distributions. This is intended for libraries that are
468 not built as part of Emacs, e.g. image libraries.
469
470 For example, specifying
471
472 --distfiles D:\distfiles\libXpm.dll
473
474 results in libXpm.dll being copied from D:\distfiles to the
475 bin directory before packaging starts.
476
477 Multiple files can be specified using multiple --distfiles arguments:
478
479 --distfiles D:\distfiles\libXpm.dll --distfiles C:\jpeglib\jpeg.dll
480
481 For packaging the binary distributions, the 'dist' make target uses
482 7-Zip (http://www.7-zip.org), which must be installed and available
483 on the Windows Path.
484
485
486 * Trouble-shooting
487
488 The main problems that are likely to be encountered when building
489 Emacs stem from using an old version of GCC, or old MinGW or W32 API
490 headers. Additionally, Cygwin ports of GNU make may require the Emacs
491 source tree to be mounted with text!=binary, because the makefiles
492 generated by configure.bat necessarily use DOS line endings. Also,
493 Cygwin ports of make must run in UNIX mode, either by specifying
494 --unix on the command line, or MAKE_MODE=UNIX in the environment.
495
496 When configure runs, it attempts to detect when GCC itself, or the
497 headers it is using, are not suitable for building Emacs. GCC version
498 2.95 or later is needed, because that is when the Windows port gained
499 sufficient support for anonymous structs and unions to cope with some
500 definitions from winnt.h that are used by addsection.c.
501 Older versions of the W32 API headers that come with Cygwin and MinGW
502 may be missing some definitions required by Emacs, or broken in other
503 ways. In particular, uniscribe APIs were added to MinGW CVS only on
504 2006-03-26, so releases from before then cannot be used.
505
506 When in doubt about correctness of what configure did, look at the file
507 config.log, which shows all the failed test programs and compiler
508 messages associated with the failures. If that doesn't give a clue,
509 please report the problems, together with the relevant fragments from
510 config.log, as bugs.
511
512 If configure succeeds, but make fails, install the Cygwin port of
513 Bash, even if the table above indicates that Emacs should be able to
514 build without sh.exe. (Some versions of Windows shells are too dumb
515 for Makefile's used by Emacs.)
516
517 If you are using certain Cygwin builds of GCC, such as Cygwin version
518 1.1.8, you may need to specify some extra compiler flags like so:
519
520 configure --with-gcc --cflags -mwin32 --cflags -D__MSVCRT__
521 --ldflags -mwin32
522
523 However, the latest Cygwin versions, such as 1.3.3, don't need those
524 switches; you can simply use "configure --with-gcc".
525
526 We will attempt to auto-detect the need for these flags in a future
527 release.
528
529 * Debugging
530
531 You should be able to debug Emacs using the debugger that is
532 appropriate for the compiler you used, namely DevStudio or Windbg if
533 compiled with MSVC, or GDB if compiled with GCC. (GDB for Windows
534 is available from the MinGW site, http://www.mingw.org/download.shtml.)
535
536 When Emacs aborts due to a fatal internal error, Emacs on Windows
537 pops up an Emacs Abort Dialog asking you whether you want to debug
538 Emacs or terminate it. If Emacs was built with MSVC, click YES
539 twice, and Windbg or the DevStudio debugger will start up
540 automatically. If Emacs was built with GCC, first start GDB and
541 attach it to the Emacs process with the "gdb -p EMACS-PID" command,
542 where EMACS-PID is the Emacs process ID (which you can see in the
543 Windows Task Manager), type the "continue" command inside GDB, and
544 only then click YES on the abort dialog. This will pass control to
545 the debugger, and you will be able to debug the cause of the fatal
546 error.
547
548 Emacs functions implemented in C use a naming convention that reflects
549 their names in lisp. The names of the C routines are the lisp names
550 prefixed with 'F', and with dashes converted to underscores. For
551 example, the function call-process is implemented in C by
552 Fcall_process. Similarly, lisp variables are prefixed with 'V', again
553 with dashes converted to underscores. These conventions enable you to
554 easily set breakpoints or examine familiar lisp variables by name.
555
556 Since Emacs data is often in the form of a lisp object, and the
557 Lisp_Object type is difficult to examine manually in a debugger,
558 Emacs provides a helper routine called debug_print that prints out a
559 readable representation of a Lisp_Object. If you are using GDB,
560 there is a .gdbinit file in the src directory which provides
561 definitions that are useful for examining lisp objects. Therefore,
562 the following tips are mainly of interest when using MSVC.
563
564 The output from debug_print is sent to stderr, and to the debugger
565 via the OutputDebugString routine. The output sent to stderr should
566 be displayed in the console window that was opened when the
567 emacs.exe executable was started. The output sent to the debugger
568 should be displayed in its "Debug" output window.
569
570 When you are in the process of debugging Emacs and you would like to
571 examine the contents of a Lisp_Object variable, pop up the QuickWatch
572 window (QuickWatch has an eyeglass symbol on its button in the
573 toolbar). In the text field at the top of the window, enter
574 debug_print(<variable>) and hit return. For example, start and run
575 Emacs in the debugger until it is waiting for user input. Then click
576 on the Break button in the debugger to halt execution. Emacs should
577 halt in ZwUserGetMessage waiting for an input event. Use the Call
578 Stack window to select the procedure w32_msp_pump up the call stack
579 (see below for why you have to do this). Open the QuickWatch window
580 and enter debug_print(Vexec_path). Evaluating this expression will
581 then print out the contents of the lisp variable exec-path.
582
583 If QuickWatch reports that the symbol is unknown, then check the call
584 stack in the Call Stack window. If the selected frame in the call
585 stack is not an Emacs procedure, then the debugger won't recognize
586 Emacs symbols. Instead, select a frame that is inside an Emacs
587 procedure and try using debug_print again.
588
589 If QuickWatch invokes debug_print but nothing happens, then check the
590 thread that is selected in the debugger. If the selected thread is
591 not the last thread to run (the "current" thread), then it cannot be
592 used to execute debug_print. Use the Debug menu to select the current
593 thread and try using debug_print again. Note that the debugger halts
594 execution (e.g., due to a breakpoint) in the context of the current
595 thread, so this should only be a problem if you've explicitly switched
596 threads.
597
598 \f
599 This file is part of GNU Emacs.
600
601 GNU Emacs is free software: you can redistribute it and/or modify
602 it under the terms of the GNU General Public License as published by
603 the Free Software Foundation, either version 3 of the License, or
604 (at your option) any later version.
605
606 GNU Emacs is distributed in the hope that it will be useful,
607 but WITHOUT ANY WARRANTY; without even the implied warranty of
608 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
609 GNU General Public License for more details.
610
611 You should have received a copy of the GNU General Public License
612 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.