tests/once.c

   1 #define __DARWIN_NON_CANCELABLE 0
   2 #include <pthread.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <unistd.h>
   6
   7 static pthread_once_t once = PTHREAD_ONCE_INIT;
   8 static int x = 0;
   9
  10 void cancelled(void)
  11 {
  12     printf("thread cancelled.\n");
  13 }
  14
  15 void oncef(void)
  16 {
  17     printf("in once handler: %p\n", pthread_self());
  18     sleep(5);
  19     x = 1;
  20 }
  21
  22 void* a(void *ctx)
  23 {
  24     printf("a started: %p\n", pthread_self());
  25     pthread_cleanup_push((void*)cancelled, NULL);
  26     pthread_once(&once, oncef);
  27     pthread_cleanup_pop(0);
  28     printf("a finished\n");
  29     return NULL;
  30 }
  31
  32 void* b(void *ctx)
  33 {
  34     sleep(1); // give enough time for a() to get into pthread_once
  35     printf("b started: %p\n", pthread_self());
  36     pthread_once(&once, oncef);
  37     printf("b finished\n");
  38     return NULL;
  39 }
  40
  41 int main(void)
  42 {
  43     pthread_t t1;
  44     if (pthread_create(&t1, NULL, a, NULL) != 0) {
  45         fprintf(stderr, "failed to create thread a.");
  46         exit(1);
  47     }
  48
  49     pthread_t t2;
  50     if (pthread_create(&t2, NULL, b, NULL) != 0) {
  51         fprintf(stderr, "failed to create thread b.");
  52         exit(1);
  53     }
  54
  55     sleep(2);
  56     pthread_cancel(t1);
  57
  58     pthread_join(t1, NULL);
  59     pthread_join(t2, NULL);
  60     exit(0);
  61 }