pthread_test/uninit.cc

   1 /**
   2  * @file uninit.cc
   3  * @brief Uninitialized loads test
   4  *
   5  * This is a test of the "uninitialized loads" code. While we don't explicitly
   6  * initialize y, this example's synchronization pattern should guarantee we
   7  * never see it uninitialized.
   8  */
   9 #include <stdio.h>
  10 #include <pthread.h>
  11 #include <atomic>
  12
  13 //#include "librace.h"
  14
  15 std::atomic_int x;
  16 std::atomic_int y;
  17
  18 static void *a(void *obj)
  19 {
  20         int flag = x.load(std::memory_order_acquire);
  21         printf("flag: %d\n", flag);
  22         if (flag == 2)
  23                 printf("Load: %d\n", y.load(std::memory_order_relaxed));
  24         return NULL;
  25 }
  26
  27 static void *b(void *obj)
  28 {
  29         printf("fetch_add: %d\n", x.fetch_add(1, std::memory_order_relaxed));
  30         return NULL;
  31 }
  32
  33 static void *c(void *obj)
  34 {
  35         y.store(3, std::memory_order_relaxed);
  36         x.store(1, std::memory_order_release);
  37         return NULL;
  38 }
  39
  40 int user_main(int argc, char **argv)
  41 {
  42         pthread_t t1, t2, t3;
  43
  44         std::atomic_init(&x, 0);
  45
  46         printf("Main thread: creating 3 threads\n");
  47         pthread_create(&t1,NULL, &a, NULL);
  48         pthread_create(&t2,NULL, &b, NULL);
  49         pthread_create(&t3,NULL, &c, NULL);
  50
  51         pthread_join(t1,NULL);
  52         pthread_join(t2,NULL);
  53         pthread_join(t3,NULL);
  54         printf("Main thread is finished\n");
  55
  56         return 0;
  57 }