Question

is there a “built-in” way to know the exit code passed to exit inside an exit handler installed with atexit?

For example, if a call exit(EXIT_FAILURE), my handler will perform different operations than in case of exit(EXIT_SUCCESS).

I could solve that with a global variable, but that would negate the comfort of calling exit no matter where in my program.

Answer 1

With atexit no. But you could use the on_exit function :

Function: int on_exit (void (*function)(int status, void *arg), void *arg)

This function is a somewhat more powerful variant of atexit. It accepts two
arguments, a function function and an arbitrary pointer
arg. At normal program termination, the function is called with two
arguments: the status value passed to exit, and the arg.

This function is included in the GNU C Library only for compatibility
for SunOS, and may not be supported by other implementations.

Well, you must use gnu libc …