#define _GNU_SOURCE

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

int main(int argc, char **argv) {
  printf("beginning of main\n");

  // create a sigset with just SIGINT.
  sigset_t sigint;
  sigemptyset(&sigint);
  sigaddset(&sigint, SIGINT);

  // unblock signal. if it's (still) pending, it should kill the process.
  sigprocmask(SIG_UNBLOCK, &sigint, NULL);

  printf("sig unblocked\n");

  // block it.
  sigprocmask(SIG_BLOCK, &sigint, NULL);
  printf("sig blocked\n");

  // raise it. The signal is blocked, so this will set the signal pending, but
  // not deliver it yet.
  raise(SIGINT);
  printf("sig raised\n");

  // re-exec ourselves
  execv(argv[0], argv);

  return 0;
}

$ ./a.out 
beginning of main
sig unblocked
sig blocked
sig raised
beginning of main