1  #include <signal.h>
       2  #include <stdio.h>
       3  #include <stdlib.h>
       4  #include <time.h>
       5  #include <unistd.h>
       6  #include <stdint.h>
       7  
       8  volatile int gotit = 0;
       9  
      10  static void
      11  alarm_handler (int signal)
      12  {
      13      gotit = 1;
      14  }
      15  
      16  
      17  int
      18  main (int argc, char ** argv)
      19  {
      20    clock_t start, stop;
      21  
      22    if (signal(SIGALRM, alarm_handler) == SIG_ERR)
      23      {
      24        perror ("signal");
      25        exit (1);
      26      }
      27    alarm(1);
      28    start = clock ();
      29    while (!gotit);
      30    stop = clock ();
      31  
      32    printf ("%jd clock ticks per second (start=%jd,stop=%jd)\n",
      33  	  (intmax_t) (stop - start), (intmax_t) start, (intmax_t) stop);
      34    printf ("CLOCKS_PER_SEC=%jd, sysconf(_SC_CLK_TCK)=%ld\n",
      35  	  (intmax_t) CLOCKS_PER_SEC, sysconf(_SC_CLK_TCK));
      36    return 0;
      37  }