我写了以下代码:
void *produce(void* arg)
{
buffer* buff = (buffer *) arg;
while (1)
{
pthread_mutex_lock(&mutex);
if (elements_produced == JOB_SIZE)
{
pthread_mutex_unlock(&mutex);
pthread_exit(NULL);
}
elements_produced++;
while (buff->in_buff == CAPACITY)
{
pthread_cond_wait(&cond_empty, &mutex);
}
// produce
buff->buffer[buff->tail] = rand();
sum_produced += buff->buffer[buff->tail];
printf(">produced %d\n", buff->buffer[buff->tail]);
buff->tail = (buff->tail + 1) % CAPACITY;
buff->in_buff++;
pthread_cond_signal(&cond_empty);
pthread_mutex_unlock(&mutex);
}
pthread_exit(NULL);
}
void *consume(void* arg)
{
int rc;
buffer* buff = (buffer *) arg;
while (1)
{
rc = pthread_mutex_lock(&mutex);
if (elements_consumed == JOB_SIZE)
{
pthread_mutex_unlock(&mutex);
pthread_exit(NULL);
return 0;
}
elements_consumed++;
while (buff->in_buff == 0)
{
rc = pthread_cond_wait(&cond_empty, &mutex);
}
// consume
printf("<consumed %d\n", buff->buffer[buff->head]);
sum_consumed += buff->buffer[buff->head];
buff->head = (buff->head + 1) % CAPACITY;
buff->in_buff--;
pthread_cond_signal(&cond_full);
pthread_mutex_unlock(&mutex);
}
pthread_exit(NULL);
return 0;
}
所有变量都已正确初始化。任务是生成JOB_SIZE元素并使用它们。它不时陷入死锁。我对posix线程很陌生,所以我可能遗漏了一些非常明显的东西(在java / C#/ python中多次生产者/消费者,但现在我真的被卡住了)。我知道使用信号量更容易,但我需要这样做。
有什么建议吗?
答案 0 :(得分:3)
你在两边使用cond_empty进行等待。你发信号(但从不等待)cond_full。