A list of things to remember when debugging a C program

These go for C++ as well. Assuming gcc/g++ and gdb.

• Compile with -Wall and pay attention to warnings.
• Turn off compiler optimization. Remove -O from your CFLAGS.
• Turn on debugging. Add -g to your CFLAGS.
• Set appropriate breakpoints.
• There is nothing wrong with throwing in a printf statement to narrow down your search. Use fprintf to print to stderr.
• gdb --args ./program --program-args
• break filename:lineno
• Use valgrind to eliminate memory leaks and clean things up. If you can't trigger it while debugging, it's probably a memory bug. (valgrind --leak-check=full -v --log-file=vg.out ./program --program-args)
• Define the error condition, then determine how it got that way.
• When you find the bug, look for similar bugs in all your other code.