Call another function when main() exits

Question

Is it possible to call an extra function when main() exits in C?

Thanks!

Answer 1

You can register functions to run after main exits using the atexit function.

MSDN has a nice succinct example of how this is done. Basically, the functions registered with atexit are executed in reverse order of when they were registered.

Answer 2

Try the atexit() function:

void myfunc() {
    /* Called when the program ends */
}

int main( int arc, char *argv[] ) {
    atexit( myfunc );
    ...
    return 0;
}

Answer 3

Great question and answers. Just a side note. Abuse of a similar feature in Delphi libraries led to applications which are annoyingly slow on close.

Answer 4

While atexit() is the standard for registering a function to run at process termination, GCC provides a destructor function attribute^* that causes a function to be called automatically when main() has completed or exit() has been called.

void __attribute__ ((destructor)) my_fini(void);

^{* GCC specific}