读者线程没有退出 - Posix Pthreads

Question

我必须使用posix pthreads为读者编写器问题创建一个解决方案，我已将我的代码缩减为与C混合的伪代码以减小代码的大小。

编写器线程完成正常，但读取器线程永远不会终止/退出所以Reader join永远等待，程序挂起。

我相信它与阅读器功能中的等待条件pthread_cond_wait(&qElement, &mutex);有关。它可能正在等待终止的作者线程发出信号。我已经尝试用if(!finished)封装它，所以只有在编写器仍处于活动状态但仍然没有工作的情况下它才会等待。

我不知道该怎么做，并认为它是我的pthread处理的逻辑错误。

真的很感激帮助。

Global variables in header file : 

#define TRUE 1
#define FALSE 0

int finished = FALSE

pthread_cond_t qServiced = PTHREAD_COND_INITIALIZER;
pthread_cond_t qEmpty = PTHREAD_COND_INITIALIZER;
pthread_cond_t qElement = PTHREAD_COND_INITIALIZER;

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

int main()
{
    Create 1 writer thread
    Create 2 reader threads

    Writer join <- Success 
    Reader join <- Program hangs here


void* writer()
{
    int totalQueued = 0; 
    int tasks = 20; 

    while(!finished)
    {
        pthread_mutex_lock(&mutex); 

        while(isFull(q))
        {
            pthread_cond_wait(&qEmpty, &mutex); 
        }

        if(totalQueued < tasks)
        {
            for(j = 0; j < 2; j++) //Add 2 numbers at a time 
            {
                if(!(isFull(q)))
                {
                    //Assume random numbers added to queue 
                    totalQueued++;
                }
            }
            pthread_cond_signal(&qElement);
            pthread_cond_wait(&qServiced, &mutex);
        }
        else
        {
            finished = TRUE; 
        }
        pthread_mutex_unlock(&mutex); 
    } 

    //Thread exits
}

void* reader()
{
    while(!finished)
    {
        pthread_mutex_lock(&mutex);

        while(isEmpty(q)) //If the queue is empty 
        {
            pthread_cond_signal(&qEmpty);
            pthread_cond_wait(&qElement, &mutex);
        }

        int n = dequeue(q); 
        printf("%d
", n); 

        pthread_cond_signal(&qServiced); //Signal that task has been serviced
        pthread_mutex_unlock(&mutex);
    }
}