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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-11-27 07:37:33 +00:00
emacs/nt/INSTALL
Eli Zaretskii a6fc3b5c53 Support MSVC build with newer versions of Visual Studio.
Small portions of the changes by Fabrice Popineau <fabrice.popineau@supelec.fr>.

 src/makefile.w32-in (TAGS-gmake): Don't use $(patsubst ...), as
 Nmake barfs on that.  Use $(OBJ*_c) variables instead, defined on
 nt/gmake.defs.
 src/lisp.h (ENUM_BF): New macro, for enumerated types in bitfields,
 which are not supported by MSVC.
 (Lisp_Symbol, Lisp_Misc_Any, Lisp_Marker, Lisp_Misc_Overlay)
 (Lisp_Save_Value, Lisp_Free): Use ENUM_BF for enumerated types in
 bitfields.
 (Lisp_Object) [USE_LISP_UNION_TYPE]: Use ENUM_BF for enumerated
 types in bitfields.
 (DEFUN) [_MSC_VER]: Define in a different way for MSVC.
 src/w32fns.c [_MSC_VER]: DECLARE_HANDLE for any MSVC version.
 src/w32.c: Don't include w32api.h for MSVC.
 (init_environment) [_MSC_VER]: Call sys_access, not _access.
 src/s/ms-w32.h <sigset_t, ssize_t> [_MSC_VER]: Typedefs for MSVC.
 [_MSC_VER]: Include sys/timeb.h, sys/stat.h, and signal.h.
 (fstat, stat, utime) [_MSC_VER]: Redirect to their sys_* cousins.
 (malloc, free, realloc, calloc) [_MSC_VER]: Always redirect to the
 e_* cousins.
 (alloca) [_MSC_VER]: Define to _alloca.
 src/lisp.h (DECL_ALIGN) [_MSC_VER]: Define for MSVC.
 src/regex.c <re_char> [_MSC_VER]: A separate definition for MSVC.
 nt/makefile.w32-in (clean-other-dirs-nmake)
 (distclean-other-dirs-nmake, maintainer-clean-other-dirs-nmake):
 Update for current structure of doc/ subdirectories.
 nt/gmake.defs (OBJ0_c, OBJ1_c, OBJ2_c): New variables.
 nt/INSTALL: Update for newer versions of MSVC.
 lib/makefile.w32-in (FRC): New dummy target.
 (TAGS): Depend on FRC.

Fixes: debbugs:9960
2011-11-05 13:34:56 +02:00

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Building and Installing Emacs on Windows
(from 95 to 7 and beyond)
Copyright (C) 2001-2011 Free Software Foundation, Inc.
See the end of the file for license conditions.
* For the impatient
Here are the concise instructions for configuring and building the
native Windows binary of Emacs, for those who want to skip the
complex explanations and ``just do it'':
Do not use this recipe with Cygwin. For building on Cygwin,
use the normal installation instructions, ../INSTALL.
If you have a Cygwin or MSYS port of Bash on your Path, you will be
better off removing it from PATH. (For details, search for "MSYS
sh.exe" below.)
1. Change to the `nt' directory (the directory of this file):
cd nt
2. Run configure.bat.
2a.If you use MSVC, set up the build environment by running the
SetEnv.cmd batch file from the appropriate SDK directory. (Skip
this step if you are using MinGW.) For example:
"C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd" /x86 /Debug
if you are goiung to compile a debug version, or
"C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd" /x86 /Release
if you are going to compile an optimized version.
2b.From the COMMAND.COM/CMD.EXE command prompt type:
configure
From a Unixy shell prompt:
cmd /c configure.bat
or
command.com /c configure.bat
3. Run the Make utility suitable for your environment. If you build
with the Microsoft's Visual C compiler:
nmake
For the development environments based on GNU GCC (MinGW, MSYS,
Cygwin - but see notes about Cygwin make below), depending on how
Make is called, it could be:
make
or
mingw32-make
or
gnumake
or
gmake
(If you are building from Bazaar, say "make bootstrap" or "nmake
bootstrap" instead, and avoid using Cygwin make.)
With GNU Make, you can use the -j command-line option to have
Make execute several commands at once, like this:
gmake -j 2 XMFLAGS="-j 2"
The XMFLAGS variable overrides the default behavior of GNU Make
on Windows, whereby recursive Make invocations reset the maximum
number of simultaneous commands to 1. The above command allows
up to 4 simultaneous commands at once in the top-level Make, and
up to 3 in each one of the recursive Make's.
4. Generate the Info manuals (only if you are building out of Bazaar,
and if you have makeinfo.exe installed):
make info
(change "make" to "nmake" if you use MSVC).
5. Install the produced binaries:
make install
That's it!
If these short instructions somehow fail, read the rest of this
file.
* Preliminaries
If you want to build a Cygwin port of Emacs, use the instructions in
the INSTALL file in the main Emacs directory (the parent of this
directory). These instructions are for building a native Windows
binary of Emacs.
If you used WinZip to unpack the distribution, we suggest to
remove the files and unpack again with a different program!
WinZip is known to create some subtle and hard to debug problems,
such as converting files to DOS CR-LF format, not creating empty
directories, etc. We suggest to use djtarnt.exe from the GNU FTP
site.
In addition to this file, you should also read INSTALL.BZR in the
parent directory, and make sure that you have a version of
"touch.exe" in your path, and that it will create files that do not
yet exist.
* Supported development environments
To compile Emacs, you will need either Microsoft Visual C++ 2.0, or
later and nmake, or a Windows port of GCC 2.95 or later with MinGW
and W32 API support and a port of GNU Make. You can use the Cygwin
ports of GCC, but Emacs requires the MinGW headers and libraries to
build (latest versions of the Cygwin toolkit, at least since v1.3.3,
include the MinGW headers and libraries as an integral part).
The rest of this file assumes you have a working development
environment. If you just installed such an environment, try
building a trivial C "Hello world" program, and see if it works. If
it doesn't work, resolve that problem first! If you use Microsoft
Visual Studio .NET 2003, don't forget to run the VCVARS32.BAT batch
file from the `Bin' subdirectory of the directory where you have
installed VS.NET. With other versions of MSVC, run the SetEnv.cmd
batch file from the `Bin' subdirectory of the directory where you
have the SDK installed.
If you use the MinGW port of GCC and GNU Make to build Emacs, there
are some compatibility issues wrt Make and the shell that is run by
Make, either the standard COMMAND.COM/CMD.EXE supplied with Windows
or sh.exe, a port of a Unixy shell. For reference, below is a list
of which builds of GNU Make are known to work or not, and whether
they work in the presence and/or absence of sh.exe, the Cygwin port
of Bash. Note that any version of Make that is compiled with Cygwin
will only work with Cygwin tools, due to the use of Cygwin style
paths. This means Cygwin Make is unsuitable for building parts of
Emacs that need to invoke Emacs itself (leim and "make bootstrap",
for example). Also see the Trouble-shooting section below if you
decide to go ahead and use Cygwin make.
In addition, using 4NT or TCC as your shell is known to fail the
build process, at least since 4NT version 3.01. Use CMD.EXE, the
default Windows shell, instead. MSYS sh.exe also appears to cause
various problems, e.g., it is known to cause failures in commands
like "cmd /c FOO" in the Makefiles, because it thinks "/c" is a
Unix-style file name that needs conversion to the Windows format.
If you have MSYS installed, try "make SHELL=cmd.exe" to force the
use of cmd.exe instead of the MSYS sh.exe.
sh exists no sh
cygwin b20.1 make (3.75): fails[1, 5] fails[2, 5]
MSVC compiled gmake 3.77: okay okay
MSVC compiled gmake 3.78.1: okay okay
MSVC compiled gmake 3.79.1: okay okay
mingw32/gcc-2.92.2 make (3.77): okay okay[4]
cygwin compiled gmake 3.77: fails[1, 5] fails[2, 5]
cygwin compiled make 3.78.1: fails[5] fails[2, 5]
cygwin compiled make 3.79.1: fails[3, 5] fails[2?, 5]
cygwin compiled make 3.80: okay[6] fails?[7]
cygwin compiled make 3.81: fails fails?[7]
mingw32 compiled make 3.79.1: okay okay
mingw32 compiled make 3.80: okay okay[7]
mingw32 compiled make 3.81: okay okay[8]
Notes:
[1] doesn't cope with makefiles with DOS line endings, so must mount
emacs source with text!=binary.
[2] fails when needs to invoke shell commands; okay invoking gcc etc.
[3] requires LC_MESSAGES support to build; cannot build with early
versions of Cygwin.
[4] may fail on Windows 9X and Windows ME; if so, install Bash.
[5] fails when building leim due to the use of cygwin style paths.
May work if building emacs without leim.
[6] need to uncomment 3 lines in nt/gmake.defs that invoke `cygpath'
(look for "cygpath" near line 85 of gmake.defs).
[7] not recommended; please report if you try this combination.
[8] tested only on Windows XP.
Other compilers may work, but specific reports from people that have
tried suggest that the Intel C compiler (for example) may produce an
Emacs executable with strange filename completion behavior. Unless
you would like to assist by finding and fixing the cause of any bugs
like this, we recommend the use of the supported compilers mentioned
in the previous paragraph.
You will also need a copy of the POSIX cp, rm and mv programs. These
and other useful POSIX utilities can be obtained from one of several
projects:
* http://gnuwin32.sourceforge.net/ ( GnuWin32 )
* http://www.mingw.org/ ( MinGW )
* http://www.cygwin.com/ ( Cygwin )
* http://unxutils.sourceforge.net/ ( UnxUtils )
If you build Emacs on 16-bit versions of Windows (9X or ME), we
suggest to install the Cygwin port of Bash. That is because the
native Windows shell COMMAND.COM is too limited; the Emacs build
procedure tries very hard to support even such limited shells, but
as none of the Windows developers of Emacs work on Windows 9X, we
cannot guarantee that it works without a more powerful shell.
Additional instructions and help for building Emacs on Windows can be
found at the Emacs Wiki:
http://www.emacswiki.org/cgi-bin/wiki/WThirtyTwoInstallationKit
and on these URLs:
http://ourcomments.org/Emacs/w32-build-emacs.html
http://derekslager.com/blog/posts/2007/01/emacs-hack-3-compile-emacs-from-cvs-on-windows.ashx
Both of those pages were written before Emacs switched from CVS to
Bazaar, but the parts about building Emacs still apply in Bazaar.
The second URL has instructions for building with MSVC, as well as
with MinGW, while the first URL covers only MinGW, but has more
details about it.
* Configuring
Configuration of Emacs is now handled by running configure.bat in the
`nt' subdirectory. It will detect which compiler you have available,
and generate makefiles accordingly. You can override the compiler
detection, and control optimization and debug settings, by specifying
options on the command line when invoking configure.
To configure Emacs to build with GCC or MSVC, whichever is available,
simply change to the `nt' subdirectory and run `configure.bat' with no
options. To see what options are available, run `configure --help'.
Do NOT use the --no-debug option to configure.bat unless you are
absolutely sure the produced binaries will never need to be run under
a debugger.
Because of limitations of the stock Windows command shells, special
care is needed to pass some characters in the arguments of the
--cflags and --ldflags options. Backslashes should not be used in
file names passed to the compiler and linker via these options. Use
forward slashes instead. If the arguments to these two options
include the `=' character, like when passing a -DFOO=bar preprocessor
option, the argument with the `=' character should be enclosed in
quotes, like this:
configure --cflags "-DFOO=bar"
Support for options that include the `=' character require "command
extensions" to be enabled. (They are enabled by default, but your
system administrator could have changed that. See "cmd /?" for
details.) If command extensions are disabled, a warning message might
be displayed informing you that "using parameters that include the =
character by enclosing them in quotes will not be supported."
You may also use the --cflags and --ldflags options to pass
additional parameters to the compiler and linker, respectively; they
are frequently used to pass -I and -L flags to specify supplementary
include and library directories. If a directory name includes
spaces, you will need to enclose it in quotes, as follows
-I"C:/Program Files/GnuTLS-2.10.1/include". Note that only the
directory name is enclosed in quotes, not the entire argument. Also
note that this functionality is only supported if command extensions
are available. If command extensions are disabled and you attempt to
use this functionality you may see the following warning message
"Error in --cflags argument: ... Backslashes and quotes cannot be
used with --cflags. Please use forward slashes for filenames and
paths (e.g. when passing directories to -I)."
N.B. It is normal to see a few error messages output while configure
is running, when gcc support is being tested. These cannot be
suppressed because of limitations in the Windows 9X command.com shell.
You are encouraged to look at the file config.log which shows details
for failed tests, after configure.bat finishes. Any unexplained failure
should be investigated and perhaps reported as a bug (see the section
about reporting bugs in the file README in this directory and in the
Emacs manual).
* Optional image library support
In addition to its "native" image formats (pbm and xbm), Emacs can
handle other image types: xpm, tiff, gif, png, jpeg and experimental
support for svg.
To build Emacs with support for them, the corresponding headers must
be in the include path when the configure script is run. This can
be setup using environment variables, or by specifying --cflags
-I... options on the command-line to configure.bat. The configure
script will report whether it was able to detect the headers. If
the results of this testing appear to be incorrect, please look for
details in the file config.log: it will show the failed test
programs and compiler error messages that should explain what is
wrong. (Usually, any such failures happen because some headers are
missing due to bad packaging of the image support libraries.)
Note that any file path passed to the compiler or linker must use
forward slashes; using backslashes will cause compiler warnings or
errors about unrecognized escape sequences.
To use the external image support, the DLLs implementing the
functionality must be found when Emacs first needs them, either on the
PATH, or in the same directory as emacs.exe. Failure to find a
library is not an error; the associated image format will simply be
unavailable. Note that once Emacs has determined that a library can
not be found, there's no way to force it to try again, other than
restarting. See the variable `dynamic-library-alist' to configure the
expected names of the libraries.
Some image libraries have dependencies on one another, or on zlib.
For example, tiff support depends on the jpeg library. If you did not
compile the libraries yourself, you must make sure that any dependency
is in the PATH or otherwise accessible and that the binaries are
compatible (for example, that they were built with the same compiler).
Binaries for the image libraries (among many others) can be found at
the GnuWin32 project. PNG, JPEG and TIFF libraries are also
included with GTK, which is installed along with other Free Software
that requires it. These are built with MinGW, but they can be used
with both GCC/MinGW and MSVC builds of Emacs. See the info on
http://ourcomments.org/Emacs/w32-build-emacs.html, under "How to Get
Images Support", for more details about installing image support
libraries. Note specifically that, due to some packaging snafus in
the GnuWin32-supplied image libraries, you will need to download
_source_ packages for some of the libraries in order to get the
header files necessary for building Emacs with image support.
If GTK 2.0 is installed, addpm will arrange for its image libraries
to be on the DLL search path for Emacs.
For PNG images, we recommend to use versions 1.4.x and later of
libpng, because previous versions had security issues. You can find
precompiled libraries and headers on the GTK download page for
Windows (http://www.gtk.org/download/win32.php).
Versions 1.4.0 and later of libpng are binary incompatible with
earlier versions, so Emacs will only look for libpng libraries which
are compatible with the version it was compiled against. That
version is given by the value of the Lisp variable `libpng-version';
e.g., 10403 means version 1.4.3. The variable `dynamic-library-alist'
is automatically set to name only those DLL names that are known to
be compatible with the version given by `libpng-version'. If PNG
support does not work for you even though you have the support DLL
installed, check the name of the installed DLL against
`dynamic-library-alist' and the value of `libpng-version', and
download compatible DLLs if needed.
* Optional GnuTLS support
If configure.bat finds the gnutls/gnutls.h file in the include path,
Emacs is built with GnuTLS support by default; to avoid that you can
pass the argument --without-gnutls.
In order to support GnuTLS at runtime, a GnuTLS-enabled Emacs must
be able to find the relevant DLLs during startup; failure to do so
is not an error, but GnuTLS won't be available to the running
session.
You can get pre-built binaries (including any required DLL and the
gnutls.h file) and an installer at http://josefsson.org/gnutls4win/.
* Experimental SVG support
SVG support is currently experimental, and not built by default.
Specify --with-svg and ensure you have all the dependencies in your
include path. Unless you have built a minimalist librsvg yourself
(untested), librsvg depends on a significant chunk of GTK+ to build,
plus a few Gnome libraries, libxml2, libbz2 and zlib at runtime. The
easiest way to obtain the dependencies required for building is to
download a pre-bundled GTK+ development environment for Windows.
GTK puts its header files all over the place, so you will need to
run pkgconfig to list the include path you will need (either passed
to configure.bat as --cflags options, or set in the environment).
To use librsvg at runtime, ensure that librsvg and its dependencies
are on your PATH. If you didn't build librsvg yourself, you will
need to check with where you downloaded it from for the
dependencies, as there are different build options. If it is a
short list, then it most likely only lists the immediate
dependencies of librsvg, but the dependencies themselves have
dependencies - so don't download individual libraries from GTK+,
download and install the whole thing. If you think you've got all
the dependencies and SVG support is still not working, check your
PATH for other libraries that shadow the ones you downloaded.
Libraries of the same name from different sources may not be
compatible, this problem was encountered with libbzip2 from GnuWin32
with libcroco from gnome.org.
If you can see etc/images/splash.svg, then you have managed to get
SVG support working. Congratulations for making it through DLL hell
to this point. You'll probably find that some SVG images crash
Emacs. Problems have been observed in some images that contain
text, they seem to be a problem in the Windows port of Pango, or
maybe a problem with the way Cairo or librsvg is using it that
doesn't show up on other platforms.
* Building
After running configure, simply run the appropriate `make' program for
your compiler to build Emacs. For MSVC, this is nmake; for GCC, it is
GNU make. (If you are building out of Bazaar, say "make bootstrap" or
"nmake bootstrap" instead.)
As the files are compiled, you will see some warning messages
declaring that some functions don't return a value, or that some data
conversions will be lossy, etc. You can safely ignore these messages.
The warnings may be fixed in the main FSF source at some point, but
until then we will just live with them.
With GNU Make, you can use the -j command-line option to have Make
execute several commands at once, like this:
gmake -j 4 XMFLAGS="-j 3"
The XMFLAGS variable overrides the default behavior of GNU Make on
Windows, whereby recursive Make invocations reset the maximum number
of simultaneous commands to 1. The above command allows up to 4
simultaneous commands at once in the top-level Make, and up to 3 in
each one of the recursive Make's; you can use other numbers of jobs,
if you wish.
If you are building from Bazaar, the following commands will produce
the Info manuals (which are not part of the Bazaar sources):
make info
or
nmake info
Note that you will need makeinfo.exe (from the GNU Texinfo package)
in order for this command to succeed.
* Installing
To install Emacs after it has compiled, simply run `nmake install'
or `make install', depending on which version of the Make utility
do you have.
By default, Emacs will be installed in the location where it was
built, but a different location can be specified either using the
--prefix option to configure, or by setting INSTALL_DIR when running
make, like so:
make install INSTALL_DIR=D:/emacs
(for `nmake', type "nmake install INSTALL_DIR=D:/emacs" instead).
The install process will run addpm to setup the registry entries, and
to create a Start menu icon for Emacs.
* Make targets
The following make targets may be used by users building the source
distribution, or users who have checked out of Bazaar after
an initial bootstrapping.
make
Builds Emacs from the available sources and pre-compiled lisp files.
make install
Installs programs to the bin directory, and runs addpm to create
Start Menu icons.
make clean
Removes object and executable files produced by the build process in
the current configuration. After make clean, you can rebuild with
the same configuration using make.
make distclean
In addition to the files removed by make clean, this also removes
Makefiles and other generated files to get back to the state of a
freshly unpacked source distribution. Note that this will not remove
installed files, or the results of builds performed with different
compiler or optimization options than the current configuration.
After make distclean, it is necessary to run configure.bat followed
by make to rebuild.
make cleanall
Removes object and executable files that may have been created by
previous builds with different configure options, in addition to
the files produced by the current configuration.
make realclean
Removes the installed files in the bin subdirectory in addition to
the files removed by make cleanall.
make dist
Builds Emacs from the available sources and pre-compiled lisp files.
Packages Emacs binaries as full distribution and barebin distribution.
The following targets are intended only for use with the Bazaar sources.
make bootstrap
Creates a temporary emacs binary with lisp source files and
uses it to compile the lisp files. Once the lisp files are built,
emacs is redumped with the compiled lisp.
make recompile
Recompiles any changed lisp files after an update. This saves
doing a full bootstrap after every update. If this or a subsequent
make fail, you probably need to perform a full bootstrap, though
running this target multiple times may eventually sort out the
interdependencies.
make maintainer-clean
Removes everything that can be recreated, including compiled lisp
files, to get back to the state of a fresh Bazaar tree. After make
maintainer-clean, it is necessary to run configure.bat and make
bootstrap to rebuild. Occasionally it may be necessary to run this
target after an update.
* Creating binary distributions
Binary distributions (full and barebin distributions) can be
automatically built and packaged from source tarballs or a bzr
checkout.
When building Emacs binary distributions, the --distfiles argument
to configure.bat specifies files to be included in the bin directory
of the binary distributions. This is intended for libraries that are
not built as part of Emacs, e.g. image libraries.
For example, specifying
--distfiles D:\distfiles\libXpm.dll
results in libXpm.dll being copied from D:\distfiles to the
bin directory before packaging starts.
Multiple files can be specified using multiple --distfiles arguments:
--distfiles D:\distfiles\libXpm.dll --distfiles C:\jpeglib\jpeg.dll
For packaging the binary distributions, the 'dist' make target uses
7-Zip (http://www.7-zip.org), which must be installed and available
on the Windows Path.
* Trouble-shooting
The main problems that are likely to be encountered when building
Emacs stem from using an old version of GCC, or old MinGW or W32 API
headers. Additionally, Cygwin ports of GNU make may require the Emacs
source tree to be mounted with text!=binary, because the makefiles
generated by configure.bat necessarily use DOS line endings. Also,
Cygwin ports of make must run in UNIX mode, either by specifying
--unix on the command line, or MAKE_MODE=UNIX in the environment.
When configure runs, it attempts to detect when GCC itself, or the
headers it is using, are not suitable for building Emacs. GCC version
2.95 or later is needed, because that is when the Windows port gained
sufficient support for anonymous structs and unions to cope with some
definitions from winnt.h that are used by addsection.c.
Older versions of the W32 API headers that come with Cygwin and MinGW
may be missing some definitions required by Emacs, or broken in other
ways. In particular, uniscribe APIs were added to MinGW CVS only on
2006-03-26, so releases from before then cannot be used.
When in doubt about correctness of what configure did, look at the file
config.log, which shows all the failed test programs and compiler
messages associated with the failures. If that doesn't give a clue,
please report the problems, together with the relevant fragments from
config.log, as bugs.
If configure succeeds, but make fails, install the Cygwin port of
Bash, even if the table above indicates that Emacs should be able to
build without sh.exe. (Some versions of Windows shells are too dumb
for Makefile's used by Emacs.)
If you are using certain Cygwin builds of GCC, such as Cygwin version
1.1.8, you may need to specify some extra compiler flags like so:
configure --with-gcc --cflags -mwin32 --cflags -D__MSVCRT__
--ldflags -mwin32
However, the latest Cygwin versions, such as 1.3.3, don't need those
switches; you can simply use "configure --with-gcc".
We will attempt to auto-detect the need for these flags in a future
release.
* Debugging
You should be able to debug Emacs using the debugger that is
appropriate for the compiler you used, namely DevStudio or Windbg if
compiled with MSVC, or GDB if compiled with GCC. (GDB for Windows
is available from the MinGW site, http://www.mingw.org/download.shtml.)
When Emacs aborts due to a fatal internal error, Emacs on Windows
pops up an Emacs Abort Dialog asking you whether you want to debug
Emacs or terminate it. If Emacs was built with MSVC, click YES
twice, and Windbg or the DevStudio debugger will start up
automatically. If Emacs was built with GCC, first start GDB and
attach it to the Emacs process with the "gdb -p EMACS-PID" command,
where EMACS-PID is the Emacs process ID (which you can see in the
Windows Task Manager), type the "continue" command inside GDB, and
only then click YES on the abort dialog. This will pass control to
the debugger, and you will be able to debug the cause of the fatal
error.
Emacs functions implemented in C use a naming convention that reflects
their names in lisp. The names of the C routines are the lisp names
prefixed with 'F', and with dashes converted to underscores. For
example, the function call-process is implemented in C by
Fcall_process. Similarly, lisp variables are prefixed with 'V', again
with dashes converted to underscores. These conventions enable you to
easily set breakpoints or examine familiar lisp variables by name.
Since Emacs data is often in the form of a lisp object, and the
Lisp_Object type is difficult to examine manually in a debugger,
Emacs provides a helper routine called debug_print that prints out a
readable representation of a Lisp_Object. If you are using GDB,
there is a .gdbinit file in the src directory which provides
definitions that are useful for examining lisp objects. Therefore,
the following tips are mainly of interest when using MSVC.
The output from debug_print is sent to stderr, and to the debugger
via the OutputDebugString routine. The output sent to stderr should
be displayed in the console window that was opened when the
emacs.exe executable was started. The output sent to the debugger
should be displayed in its "Debug" output window.
When you are in the process of debugging Emacs and you would like to
examine the contents of a Lisp_Object variable, pop up the QuickWatch
window (QuickWatch has an eyeglass symbol on its button in the
toolbar). In the text field at the top of the window, enter
debug_print(<variable>) and hit return. For example, start and run
Emacs in the debugger until it is waiting for user input. Then click
on the Break button in the debugger to halt execution. Emacs should
halt in ZwUserGetMessage waiting for an input event. Use the Call
Stack window to select the procedure w32_msp_pump up the call stack
(see below for why you have to do this). Open the QuickWatch window
and enter debug_print(Vexec_path). Evaluating this expression will
then print out the contents of the lisp variable exec-path.
If QuickWatch reports that the symbol is unknown, then check the call
stack in the Call Stack window. If the selected frame in the call
stack is not an Emacs procedure, then the debugger won't recognize
Emacs symbols. Instead, select a frame that is inside an Emacs
procedure and try using debug_print again.
If QuickWatch invokes debug_print but nothing happens, then check the
thread that is selected in the debugger. If the selected thread is
not the last thread to run (the "current" thread), then it cannot be
used to execute debug_print. Use the Debug menu to select the current
thread and try using debug_print again. Note that the debugger halts
execution (e.g., due to a breakpoint) in the context of the current
thread, so this should only be a problem if you've explicitly switched
threads.
This file is part of GNU Emacs.
GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.