关于队列满的情况，额外加一个cond，表示队列未满条件就可以了。

typedef struct {
    int number;
    int *fd;
    int front;
    int rear;
    // 队列中当前元素数目
    int count;
    pthread_mutex_t mutex;
    pthread_cond_t not_empty;
    // 队列未满条件
    pthread_cond_t not_full;
} block_queue;

void block_queue_init(block_queue *blockQueue, int number) {
    blockQueue->number = number;
    blockQueue->fd = calloc(number, sizeof(int));
    blockQueue->count = blockQueue->front = blockQueue->rear = 0;
    pthread_mutex_init(&blockQueue->mutex, NULL);
    pthread_cond_init(&blockQueue->not_empty, NULL);
    pthread_cond_init(&blockQueue->not_full, NULL);
}

void block_queue_push(block_queue *blockQueue, int fd) {
    pthread_mutex_lock(&blockQueue->mutex);
    while (blockQueue->count == blockQueue->number){ //队列满
        pthread_cond_wait(&blockQueue->not_full, &blockQueue->mutex);
    }

    blockQueue->fd[blockQueue->rear] = fd;
    if (++blockQueue->rear == blockQueue->number) {
        blockQueue->rear = 0;
    }
    blockQueue->count++;
    printf("push fd %d", fd);
    pthread_cond_signal(&blockQueue->not_empty);
    pthread_mutex_unlock(&blockQueue->mutex);
}

int block_queue_pop(block_queue *blockQueue) {
    pthread_mutex_lock(&blockQueue->mutex);
    while (blockQueue->front == blockQueue->rear) // 空队列
        pthread_cond_wait(&blockQueue->not_empty, &blockQueue->mutex);
    int fd = blockQueue->fd[blockQueue->front];
    if (++blockQueue->front == blockQueue->number) {
        blockQueue->front = 0;
    }
    blockQueue->count--;
    printf("pop fd %d", fd);
    pthread_cond_signal(&blockQueue->not_full);
    // 解锁
    pthread_mutex_unlock(&blockQueue->mutex);
    return fd;
}