pthread_mutex_t and pthread_cond 混合使用

pthread_mutex_t count_lock;

pthread_cond_t count_nonzero;

int32_t _count = 0;

void * decrement_count(void *arg)

{

pthread_mutex_lock (&count_lock);

printf("decrement_count get count_lock\n");

while (_count == 0)

{

printf("decrement_count count == 0 \n");

printf("decrement_count before cond_wait \n");

pthread_cond_wait( &count_nonzero, &count_lock);

printf("decrement_count after cond_wait \n");

}

_count = _count -1;

pthread_mutex_unlock (&count_lock);

pthread_exit(nullptr);

}

void * increment_count(void *arg)

{

pthread_mutex_lock(&count_lock);

printf("increment_count get count_lock\n");

if (_count==0)

{

printf("increment_count before cond_signal\n");

pthread_cond_signal(&count_nonzero);

printf("increment_count after cond_signal\n");

}

_count=_count+1;

pthread_mutex_unlock(&count_lock);

pthread_exit(nullptr);

}

int main(void)

{

pthread_t tid1,tid2;

pthread_mutex_init(&count_lock,NULL);

pthread_cond_init(&count_nonzero,NULL);

pthread_create(&tid1,NULL,decrement_count,NULL);

sleep(2);

pthread_create(&tid2,NULL,increment_count,NULL);

sleep(10);

while(1);

return 0;

}