assgn7/timer.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4
   5 #include <signal.h>
   6 #include <time.h>
   7
   8 struct timespec *start_time, *stop_time;
   9 int done;
  10
  11 void handle_start() {
  12
  13         if(clock_gettime(CLOCK_PROCESS_CPUTIME_ID, start_time) == -1) {
  14
  15                 printf("failed to get start time.\n");
  16                 exit(1);
  17         }
  18 }
  19
  20 void handle_stop() {
  21
  22         long int start_sec, stop_sec, delta;
  23
  24         if(clock_gettime(CLOCK_PROCESS_CPUTIME_ID, stop_time) == -1) {
  25
  26                 printf("failed to get stop time.\n");
  27                 exit(1);
  28         }
  29
  30         start_sec = ((long int) start_time->tv_nsec);
  31         stop_sec  = ((long int) stop_time->tv_nsec);
  32
  33         delta = stop_sec - start_sec;
  34
  35         printf("%ld nanoseconds elapsed between signals.\n", delta);
  36
  37         done = 1;
  38 }
  39
  40 int main(int argc, char *argv[]) {
  41
  42         done = 0;
  43
  44         start_time = (struct timespec *) calloc(1, sizeof(struct timespec));
  45         stop_time  = (struct timespec *) calloc(1, sizeof(struct timespec));
  46
  47         if(signal(SIGTSTP, handle_start) == SIG_ERR ||
  48            signal(SIGCONT, handle_stop)  == SIG_ERR) {
  49
  50                 printf("could not bind signal handlers\n");
  51                 return 1;
  52         }
  53
  54         terminate_check:
  55
  56         pause();
  57
  58         if(!done)
  59                 goto terminate_check; /* sorry */
  60
  61         free(start_time);
  62         free(stop_time);
  63
  64         return 0;
  65 }