POSIX signal handling in C

signals.c

#include <stdio.h>
#include <signal.h>
#include <unistd.h>

struct sigaction old;
void onSignalTstp(int signal)
{
	// handle signal, attach old (default) handler and re-raise the signal
	printf("Signal received: SIGTSTP(%d)\n", signal);
	sigaction(SIGTSTP, &old, NULL);
	raise(SIGTSTP);
}

void onSignalCont(int signal)
{
	// handle signal, re-attach handler for SIGTSTP
	printf("Signal received: SIGCONT(%d)\n", signal);
	struct sigaction tstp = {0};
	tstp.sa_handler       = onSignalTstp;
	sigaction(SIGTSTP, &tstp, &old);
}

int main()
{
	// attach handler for SIGTSTP
	struct sigaction tstp = {0};
	tstp.sa_handler       = onSignalTstp;
	sigaction(SIGTSTP, &tstp, &old);

	// another handler for SIGCONT
	struct sigaction cont = {0};
	cont.sa_handler       = onSignalCont;
	sigaction(SIGCONT, &cont, NULL);

	int i = 0;
	while (true) {
		printf("Counting %d\n", i++);
		sleep(1);
	}

	return 0;
}