Core dump analysis using gdb

Question

I have a couple of questions regarding core dumps. I have gdb on Windows, using Cygwin.

1. What is the location of core dump file? Is it a.exe.stackdump file? (This is the only file that generated after crash) I read on other forums that the core dump file is named "core". But I don't see any file with name "core".

2. What is the command for opening and understanding core dump file?

Answer 1

1. You need to configure Cygwin to produce core dumps by including

   error_start=x:\path\to\dumper.exe
   
   in your CYGWIN environment variable (see here in section "dumper" for more information). If you didn't do this, you will only get a stacktrace -- which may also help you in diagnosing the problem, though.

2. Start gdb as follows to attach it to a core dump file:

   gdb myexecutable --core=mycorefile
   
   You can now use the usual gdb commands to print a stacktrace, examine the values of variables, and so on.

Answer 2

1. Yes, cygwin creates a.exe.stackdump files by default. You need to configure it to create cores as well (Martin's answer covers that).
2. A simple tutorial on core dump debugging can be found here