helgrind/tests/tc06_two_races.c

   1
   2 #include <pthread.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5
   6 /* Simple test program, has two races.  A happens-before detector can only
   7    ever detect one of them, though.  XXX: apparently not so; Drd and H 3.4 detect both. */
   8
   9 int unprot1 = 0, unprot2 = 0, prot = 0;
  10 pthread_mutex_t mu = PTHREAD_MUTEX_INITIALIZER;
  11
  12 void* child_fn ( void* arg )
  13 {
  14    unprot1 ++;
  15    pthread_mutex_lock( &mu );
  16    prot ++;
  17    pthread_mutex_unlock( &mu );
  18    unprot2 ++;
  19    return NULL;
  20 }
  21
  22 int main ( void )
  23 {
  24    pthread_t child;
  25
  26    if (pthread_create(&child, NULL, child_fn, NULL)) {
  27       perror("pthread_create");
  28       exit(1);
  29    }
  30
  31    unprot1 ++;
  32    pthread_mutex_lock( &mu );
  33    prot ++;
  34    pthread_mutex_unlock( &mu );
  35    unprot2 ++;
  36
  37    if (pthread_join(child, NULL)) {
  38       perror("pthread join");
  39       exit(1);
  40    }
  41
  42    return 0;
  43 }