c++ abort override

Question

Some C++ libraries call abort() function in the case of error (for example, SDL). No helpful debug information is provided in this case. It is not possible to catch abort call and to write some diagnostics log output. I would like to override this behaviour globally without rewriting/rebuilding these libraries. I would like to throw exception and handle it. Is it possible?

Answer 1

Note that abort raises the SIGABRT signal, as if it called raise(SIGABRT). You can install a signal handler that gets called in this situation, like so:

#include <signal.h>

extern "C" void my_function_to_handle_aborts(int signal_number)
{
    /*Your code goes here. You can output debugging info.
      If you return from this function, and it was called 
      because abort() was called, your program will exit or crash anyway
      (with a dialog box on Windows).
     */
}

/*Do this early in your program's initialization */
signal(SIGABRT, &my_function_to_handle_aborts);

If you can't prevent the abort calls (say, they're due to bugs that creep in despite your best intentions), this might allow you to collect some more debugging information. This is portable ANSI C, so it works on Unix and Windows, and other platforms too, though what you do in the abort handler will often not be portable. Note that this handler is also called when an assert fails, or even by other runtime functions - say, if malloc detects heap corruption. So your program might be in a crazy state during that handler. You shouldn't allocate memory - use static buffers if possible. Just do the bare minimum to collect the information you need, get an error message to the user, and quit.

Certain platforms may allow their abort functions to be customized further. For example, on Windows, Visual C++ has a function _set_abort_behavior that lets you choose whether or not a message is displayed to the user, and whether crash dumps are collected.

Answer 2

According to the man page on Linux, abort() generates a SIGABRT to the process that can be caught by a signal handler. EDIT: Ben's confirmed this is possible on Windows too - see his comment below.