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  1. #define _POSIX_C_SOURCE 199309L
  2.  
  3. #include <stdio.h>
  4. #include <time.h>
  5. #include <unistd.h>
  6.  
  7. void timespec_diff(const struct timespec * start, const struct timespec *stop,
  8.                    struct timespec *result) {
  9.     if ((stop->tv_nsec - start->tv_nsec) < 0) {
  10.         result->tv_sec = stop->tv_sec - start->tv_sec - 1;
  11.         result->tv_nsec = stop->tv_nsec - start->tv_nsec + 1000000000;
  12.     } else {
  13.         result->tv_sec = stop->tv_sec - start->tv_sec;
  14.         result->tv_nsec = stop->tv_nsec - start->tv_nsec;
  15.     }
  16.     return;
  17. }
  18.  
  19. void timespec_print(const char * description,
  20.                     const struct timespec *start, const struct timespec *stop) {
  21.     struct timespec result;
  22.     timespec_diff(start, stop, &result);
  23.     double seconds = result.tv_sec + result.tv_nsec / 1e9;
  24.     printf("times elapsed for clock '%s': %lf\n", description, seconds);
  25. 	return;
  26. }
  27.  
  28. int main(void) {
  29. 	struct timespec start_clock_realtime;
  30. 	struct timespec start_clock_monotonic;
  31. 	struct timespec start_clock_process_cputime_id;
  32. 	struct timespec start_clock_thread_cputime_id;
  33.  
  34. 	struct timespec finish_clock_realtime;
  35. 	struct timespec finish_clock_monotonic;
  36. 	struct timespec finish_clock_process_cputime_id;
  37. 	struct timespec finish_clock_thread_cputime_id;
  38.  
  39. 	clock_gettime(CLOCK_REALTIME, &start_clock_realtime);
  40. 	clock_gettime(CLOCK_MONOTONIC, &start_clock_monotonic);
  41. 	clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &start_clock_process_cputime_id);
  42. 	clock_gettime(CLOCK_THREAD_CPUTIME_ID, &start_clock_thread_cputime_id);
  43.  
  44. 	sleep(3); // seconds
  45.  
  46. 	clock_gettime(CLOCK_REALTIME, &finish_clock_realtime);
  47. 	clock_gettime(CLOCK_MONOTONIC, &finish_clock_monotonic);
  48. 	clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &finish_clock_process_cputime_id);
  49. 	clock_gettime(CLOCK_THREAD_CPUTIME_ID, &finish_clock_thread_cputime_id);
  50.  
  51. 	timespec_print("realtime", 
  52. 		&start_clock_realtime, &finish_clock_realtime);
  53. 	timespec_print("monotonic",
  54. 		&start_clock_monotonic, &finish_clock_monotonic);
  55. 	timespec_print("process cputime id",
  56. 		&start_clock_process_cputime_id, &finish_clock_process_cputime_id);
  57. 	timespec_print("thread cputime id",
  58. 		&start_clock_thread_cputime_id, &finish_clock_thread_cputime_id);
  59.  
  60. 	return 0;
  61. }
  62.  
Success #stdin #stdout 0s 9432KB
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stdin
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Standard input is empty
stdout
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times elapsed for clock 'realtime': 3.000057
times elapsed for clock 'monotonic': 3.000057
times elapsed for clock 'process cputime id': 0.000007
times elapsed for clock 'thread cputime id': 0.000007
https://ideone.com/6XcQ7d
language:
C (gcc 8.3)
created:
6 years ago
visibility:
public

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