at_quick_exit registers a function for an alternative termination-handler list. The registered function runs during quick termination rather than ordinary termination, making this route useful when normal handlers would take too long. section 8.7
Registering a quick-exit handler
int at_quick_exit(void func(void)); Call at_quick_exit with a function reference, not a function call. For example, at_quick_exit(sayGoodBye) registers sayGoodBye; sayGoodBye() would attempt to execute it immediately. section 8.7
TAKEAWAY: Use at_quick_exit when quick_exit should invoke a separate cleanup policy. Use it with care, because it deliberately bypasses the normal atexit-handler path. section 8.7
