Debugging GNU Emacs
-Copyright (C) 1985, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
- 2008, 2009, 2010 Free Software Foundation, Inc.
+Copyright (C) 1985, 2000-2012 Free Software Foundation, Inc.
See the end of the file for license conditions.
-[People who debug Emacs on Windows using Microsoft debuggers
-should read the Windows-specific section near the end of this
-document.]
+[People who debug Emacs on Windows using Microsoft debuggers should
+read the Windows-specific section near the end of this document.]
** When you debug Emacs with GDB, you should start it in the directory
where the executable was made. That directory has a .gdbinit file
handle SIGINT stop nopass
After this `handle' command, SIGINT will return control to GDB. If
-you want the C-g to cause a QUIT within Emacs as well, omit the
-`nopass'.
+you want the C-g to cause a QUIT within Emacs as well, omit the `nopass'.
A technique that can work when `handle SIGINT' does not is to store
the code for some character into the variable stop_character. Thus,
the data being used in the loop and try to determine why the loop does
not exit when it should.
+You can also trying sending Emacs SIGUSR2, which, if `debug-on-event'
+has its default value, will cause Emacs to attempt to break it out of
+its current loop and into the Lisp debugger. This feature is useful
+when a C-level debugger is not conveniently available.
+
** If certain operations in Emacs are slower than they used to be, here
is some advice for how to find out why.
numeric addresses into symbols and vice versa.
It is useful to be running under a window system.
-Then, if Emacs becomes hopelessly wedged, you can create
-another window to do kill -9 in. kill -ILL is often
-useful too, since that may make Emacs dump core or return
-to adb.
+Then, if Emacs becomes hopelessly wedged, you can create another
+window to do kill -9 in. kill -ILL is often useful too, since that
+may make Emacs dump core or return to adb.
** Debugging incorrect screen updating.
Building Emacs like that activates many assertions which scrutinize
display code operation more than Emacs does normally. (To see the
code which tests these assertions, look for calls to the `xassert'
-macros.) Any assertion that is reported to fail should be
-investigated.
+macros.) Any assertion that is reported to fail should be investigated.
Building with GLYPH_DEBUG defined also defines several helper
functions which can help debugging display code. One such function is
`dump_glyph_matrix'. If you run Emacs under GDB, you can print the
contents of any glyph matrix by just calling that function with the
matrix as its argument. For example, the following command will print
-the contents of the current matrix of the window whose pointer is in
-`w':
+the contents of the current matrix of the window whose pointer is in `w':
(gdb) p dump_glyph_matrix (w->current_matrix, 2)
because Emacs replaces the system's memory allocation functions with
its own versions, and because the dumping process might be
incompatible with the way these packages use to track allocated
-memory. Here are some of the changes you might find necessary
-(SYSTEM-NAME and MACHINE-NAME are the names of your OS- and
-CPU-specific headers in the subdirectories of `src'):
-
- - In src/s/SYSTEM-NAME.h add "#define SYSTEM_MALLOC".
+memory. Here are some of the changes you might find necessary:
- - In src/m/MACHINE-NAME.h add "#define CANNOT_DUMP"
+ - Edit configure, to set system_malloc and CANNOT_DUMP to "yes".
- Configure with a different --prefix= option. If you use GCC,
version 2.7.2 is preferred, as some malloc debugging packages
paragraph-separate: "[ \f]*$"
end:
-;;; arch-tag: fbf32980-e35d-481f-8e4c-a2eca2586e6b
HCoop / bpt / emacs.git / blobdiff