text: /* Test program that invokes the Linux system call rt_sigqueueinfo(). */
  
  #include <signal.h>
  #include <string.h>
  #include <stddef.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <syscall.h>
  #include <unistd.h>
  
  int main(int argc, char **argv)
  {
    siginfo_t *si;
    const size_t sz = sizeof(*si);
  
    if (argc == 1) {
      fprintf(stderr, "sizeof(*si) = %zu\n", sz);
      fprintf(stdout, "offsetof(siginfo_t, si_signo)  = %zd\n",
              offsetof(siginfo_t, si_signo));
      fprintf(stdout, "offsetof(siginfo_t, si_errno)  = %zd\n",
              offsetof(siginfo_t, si_errno));
      fprintf(stdout, "offsetof(siginfo_t, si_code)   = %zd\n",
              offsetof(siginfo_t, si_code));
      fprintf(stdout, "offsetof(siginfo_t, _sifields) = %zd\n",
              offsetof(siginfo_t, _sifields));
    }
    si = calloc(1, sz);
    si->si_signo = SIGWINCH;
    si->si_code = SI_QUEUE;
    si->si_pid = getpid();
    si->si_uid = getuid();
    syscall(__NR_rt_sigqueueinfo, getpid(), SIGWINCH, si);
    free(si);
    fprintf(stderr, "Done.\n");
    return 0;
  }
  