Receiver not receiving data sent via segqueue - operating-system

Question

RECEIVER
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
/*
sigval_int
sigval_ptr
*/
void signal_handler(int signum, siginfo_t *siginfo, void *ucontext) {
printf("I got value %d\n", siginfo->si_int);
}
int main() {
pid_t pid = getpid();
struct sigaction act;
printf("My PID is %d\n", pid);
act.sa_sigaction = signal_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO | SA_RESTART;
sigaction(SIGUSR1, &act, NULL);
while (1);// sleep(20);
return EXIT_SUCCESS;
}
SENDER
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/types.h>
int main(int argc, char *argv[]) {
pid_t pid;
union sigval sv;
if (argc < 2 || (pid = atoi(argv[1])) < 0) exit(EXIT_FAILURE);
sv.sival_int = 56;
printf("sender: sending %d to PID %d\n", sv.sival_int, pid);
sigqueue(pid, SIGUSR1, sv);
return EXIT_SUCCESS;
}
I am trying to run these two processes in two different terminals. First I ran the receiver to note down its PID. Next I used that pid to give command line arguments while executing sender.
The sender shows that it sent the data. But apparently the receiver did not get it. It was as if the signal handler was never invoked. Can someone help with some way to solve this.
TIA