+@node Crashing
+@subsection When Emacs Crashes
+
+@cindex crash report
+@cindex backtrace
+@cindex @file{emacs_backtrace.txt} file, MS-Windows
+ Emacs is not supposed to crash, but if it does, it produces a
+@dfn{crash report} prior to exiting. The crash report is printed to
+the standard error stream. If Emacs was started from a graphical
+desktop on a GNU or Unix system, the standard error stream is commonly
+redirected to a file such as @file{~/.xsession-errors}, so you can
+look for the crash report there. On MS-Windows, the crash report is
+written to a file named @file{emacs_backtrace.txt} in the current
+directory of the Emacs process, in addition to the standard error
+stream.
+
+ The format of the crash report depends on the platform. On some
+platforms, such as those using the GNU C Library, the crash report
+includes a @dfn{backtrace} describing the execution state prior to
+crashing, which can be used to help debug the crash. Here is an
+example for a GNU system:
+
+@example
+Fatal error 11: Segmentation fault
+Backtrace:
+emacs[0x5094e4]
+emacs[0x4ed3e6]
+emacs[0x4ed504]
+/lib64/libpthread.so.0[0x375220efe0]
+/lib64/libpthread.so.0(read+0xe)[0x375220e08e]
+emacs[0x509af6]
+emacs[0x5acc26]
+@dots{}
+@end example
+
+@noindent
+The number @samp{11} is the system signal number corresponding to the
+crash---in this case a segmentation fault. The hexadecimal numbers
+are program addresses, which can be associated with source code lines
+using a debugging tool. For example, the GDB command
+@samp{list *0x509af6} prints the source-code lines corresponding to
+the @samp{emacs[0x509af6]} entry. If your system has the
+@command{addr2line} utility, the following shell command outputs a
+backtrace with source-code line numbers:
+
+@example
+sed -n 's/.*\[\(.*\)]$/\1/p' @var{backtrace} |
+ addr2line -Cfip -e @var{bindir}/@var{emacs-binary}
+@end example
+
+@noindent
+Here, @var{backtrace} is the name of a text file containing a copy of
+the backtrace, @var{bindir} is the name of the directory that
+contains the Emacs executable, and @var{emacs-binary} is the name of
+the Emacs executable file, normally @file{emacs} on GNU and Unix
+systems and @file{emacs.exe} on MS-Windows and MS-DOS.
+
+@cindex core dump
+ Optionally, Emacs can generate a @dfn{core dump} when it crashes, on
+systems that support core files. A core dump is a file containing
+voluminous data about the state of the program prior to the crash,
+usually examined by loading it into a debugger such as GDB@. On many
+platforms, core dumps are disabled by default, and you must explicitly
+enable them by running the shell command @samp{ulimit -c unlimited}
+(e.g., in your shell startup script).
+