signal_handler
action.sa_handler = (__sighandler_t)signal_handler;
signal(SIGUSR1, &signal_handler);
action.sa_sigaction = signal_handler;
if (signal(SIGSEGV, signal_handler) == SIG_ERR) {
if (signal(SIGUSR1, signal_handler) == SIG_ERR) {
if (signal(SIGUSR1, signal_handler) == SIG_ERR) {