上面这个代码我在linux用gcc编译了，但是运行的时候一直在阻塞

非常抱歉，代码中确实存在问题。在条件变量的等待和发送信号之间，需要解锁互斥锁，以便其他线程能够获取互斥锁并发送信号。以下是修正后的代码：

#include <stdio.h>
#include <pthread.h>

pthread_mutex_t mutex;
pthread_cond_t cond_zero, cond_even, cond_odd;

int count = 0;

void* zero(void* arg) {
    while (count <= 7) {
        pthread_mutex_lock(&mutex);
        
        if (count == 0) {
            printf("0");
            count++;
            pthread_cond_signal(&cond_even);
        }
        else {
            pthread_cond_wait(&cond_zero, &mutex);
        }
        
        pthread_mutex_unlock(&mutex);
    }
    
    return NULL;
}

void* even(void* arg) {
    while (count <= 7) {
        pthread_mutex_lock(&mutex);
        
        if (count % 2 == 0 && count != 0) {
            printf("%d", count);
            count++;
            pthread_cond_signal(&cond_odd);
        }
        else {
            pthread_cond_wait(&cond_even, &mutex);
        }
        
        pthread_mutex_unlock(&mutex);
    }
    
    return NULL;
}

void* odd(void* arg) {
    while (count <= 7) {
        pthread_mutex_lock(&mutex);
        
        if (count % 2 != 0) {
            printf("%d", count);
            count++;
            pthread_cond_signal(&cond_zero);
        }
        else {
            pthread_cond_wait(&cond_odd, &mutex);
        }
        
        pthread_mutex_unlock(&mutex);
    }
    
    return NULL;
}

int main() {
    pthread_t threads[3];
    
    pthread_mutex_init(&mutex, NULL);
    pthread_cond_init(&cond_zero, NULL);
    pthread_cond_init(&cond_even, NULL);
    pthread_cond_init(&cond_odd, NULL);
    
    pthread_create(&threads[0], NULL, zero, NULL);
    pthread_create(&threads[1], NULL, even, NULL);
    pthread_create(&threads[2], NULL, odd, NULL);
    
    for (int i = 0; i < 3; i++) {
        pthread_join(threads[i], NULL);
    }
    
    pthread_mutex_destroy(&mutex);
    pthread_cond_destroy(&cond_zero);
    pthread_cond_destroy(&cond_even);
    pthread_cond_destroy(&cond_odd);
    
    printf("\n");
    
    return 0;
}

在修正后的代码中，我们在条件变量的等待和发送信号之间添加了互斥锁的解锁操作（pthread_mutex_unlock）。这样，等待线程在等待期间可以释放互斥锁，允许其他线程获取互斥锁并发送信号。

重新编译并运行代码，应该能够正确地打印出预期的结果。感谢您的指出，并再次对之前的回答中的错误表示歉意。