hupme.c: look at siginfo_t from SIGHUP

hupme.c

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

int signo;
int code;
int sigerrno;
pid_t pid;
uid_t uid;
int value;

void
hup(int sig, siginfo_t *sip, void *ctx)
{
	signo = sip->si_signo;
	code = sip->si_code;
	sigerrno = sip->si_errno;
	pid = sip->si_pid;
	uid = sip->si_uid;
	value = sip->si_value.sival_int;
}

int
main(void)
{
	struct sigaction sa = {};
	pid_t me = getpid();

	sa.sa_sigaction = hup;
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = SA_SIGINFO;
	sigaction(SIGHUP, &sa, NULL);
	kill(me, SIGHUP);
	printf("signo = %d %s\n", signo, signo == SIGHUP ? "SIGHUP" : "?");
	printf("code = %d %s\n", code, code == SI_USER ? "SI_USER" : "?");
	printf("errno = %d\n", sigerrno);
	printf("pid = %d, I'm %d\n", (int)pid, (int)me);
	printf("uid = %d, I'm %d\n", (int)uid, (int)getuid());
	printf("value = %d\n", value);
}