c++ - pthreads 只创建一个线程

Question

我不明白为什么第一个线程被创建并通过 while 循环运行而不允许其他线程也运行。我确实在它进入休眠状态之前专门解锁，以便创建其他线程。我认为我必须一次创建所有线程才能使其工作，但这不会使其成为非线程安全的吗？

主要内容:

Producer *producers[NUM_PTHREADS];
    for (i = 0; i < NUM_PTHREADS; i++) {
       tn[i] = i;
       producers[i] = new Producer(producer_id);
       pthread_create(producers[i]->getThread(),NULL,produce,producers[i]);
       pthread_join(*(producers[i]->getThread()),NULL);
       producer_id++;
    }

从 pthread_create 运行:

void *produce(void* elem){
    Producer *producer;
    producer = (Producer*)elem;
    while(1){
       pthread_mutex_lock(&pmutex);
       printf("Hi, this is thread %d\n",producer->getId());
       producer->makeProduct(product_id);
       product_id++;
       printf("Made product with thread: %d, product_id: %d\n",producer->getId(),product_id);
       pthread_mutex_unlock(&pmutex);
       producer->sleep();
    }
 }

示例输出:

Hi, this is thread 0
Made product with thread: 0, product_id: 1
Hi, this is thread 0
Made product with thread: 0, product_id: 2
Hi, this is thread 0
Made product with thread: 0, product_id: 3
Hi, this is thread 0
Made product with thread: 0, product_id: 4
Hi, this is thread 0
Made product with thread: 0, product_id: 5
Hi, this is thread 0
Made product with thread: 0, product_id: 6
Hi, this is thread 0
Made product with thread: 0, product_id: 7
Hi, this is thread 0
Made product with thread: 0, product_id: 8
Hi, this is thread 0
Made product with thread: 0, product_id: 9
Hi, this is thread 0
Made product with thread: 0, product_id: 10

Answer 1

这个调用:

 pthread_join(*(producers[i]->getThread()),NULL);

一直等到您在它之前的行上创建的线程结束，并且您的 produce() 线程永远不会结束，因此您只会创建 1 个线程。