display all blocked and pending signals at one time - c

Question

The following program checks if a signal is pending. I use the sigpending function to return blocked (or waiting) signals. The problem is that I don't want this, I would like to display all the blocked and pending signals at some point, how can I do that? What should I change?
code:
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
void catcher(int signum) {
puts("inside catcher!");
if (signum != 0)
perror("signum error");
}
void check_pending(int signum, char * signame) {
sigset_t sigset;
if (sigpending( & sigset) != 0)
perror("sigpending() error");
else if (sigismember( & sigset, signum))
printf("a %s signal is pending\n", signame);
else
printf("no %s signals are pending\n", signame);
}
int main() {
struct sigaction sigact;
sigset_t sigset;
sigemptyset( & sigact.sa_mask);
sigact.sa_flags = 0;
sigact.sa_handler = catcher;
if (sigaction(SIGUSR1, & sigact, NULL) != 0)
perror("sigaction() error");
else {
sigemptyset( & sigset);
sigaddset( & sigset, SIGUSR1);
if (sigprocmask(SIG_SETMASK, & sigset, NULL) != 0)
perror("sigprocmask() error");
else {
puts("SIGUSR1 signals are now blocked");
kill(getpid(), SIGUSR1);
printf("after kill: ");
check_pending(SIGUSR1, "SIGUSR1");
sigemptyset( & sigset);
sigprocmask(SIG_SETMASK, & sigset, NULL);
puts("SIGUSR1 signals are no longer blocked");
check_pending(SIGUSR1, "SIGUSR1");
}
}
}

Answer 1

Use sigignore to dispose the signal. Program below will check pending signals in 1s intervals and display theirs numbers. Terminate with sending SIGTERM.
#define _XOPEN_SOURCE 500
#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
int main() {
int i;
sigset_t sigset;
printf("my pid is %d\n", getpid());
sigfillset(&sigset);
sigprocmask(SIG_SETMASK, &sigset, NULL);
while (1) {
sigpending(&sigset);
for (i = 1; i < 32; ++i) {
if (sigismember(&sigset, i)) {
printf("signal %d pending\n", i);
sigignore(i);
if (i == SIGTERM) {
exit(0);
}
}
}
sleep(1);
}
return 0;
}