Question

我试图让我的输出

Starting Professor 1
Starting Professor 2
Starting Professor 3
...

但是我从来没有得过＃34;开始教授1＆＃34;当num_professors = 2.我想制作一个id数组会保存id的地址的整个传入，但显然不是。我要为这个项目做大约70件其他的事情，并且在这个简单的事情上有一个障碍（可能需要几秒钟的时间来修复），至少可以说是非常令人沮丧的。非常感谢

void * professorFunc(void *p){
    sem_wait(&workAssignment);
    if(buffer == 0){
            buffer++;
            Professor *professor = (Professor*)p;
            fprintf(stdout,"Starting Professor %d\n", *professor->id);
    }
    buffer = 0;
    sem_post(&workAssignment);
    pthread_exit(0);
}
int main(int argc, char ** argv){
//Semaphore intialization
    buffer = 0;
    if(sem_init(&workAssignment, 0, 1)){
            printf("Could not initialize semaphore.\n");
            exit(1);
    }

    //Creating threads
    pthread_t professor[num_professors];
    Professor *p;
    int ids[num_professors];
    int i;
    p = malloc (sizeof (*p) * num_professors);

    for(i = 0; i < num_professors; ++i){
            ids[i] = i + 1;
            p->id = &ids[i];
            //printf("Id: %d\n", *p->id);
            if(pthread_create(&professor[i], NULL, professorFunc, p) != 0){
                    perror("pthread_create");
                    exit(1);
            }
            //printf("yo I'm here after function now\n");
    }
    for(i = 0; i < num_professors; ++i){
            if(pthread_join(professor[i], NULL) != 0){
                    perror("pthread_join");
                    exit(1);
            }
    }
    free(p);
}

Answer 1

这一行：

if(pthread_create(&professor[i], NULL, professorFunc, p) != 0){

应该是：

if(pthread_create(&professor[i], NULL, professorFunc, &p[i]) != 0){

在pthreads中获取ID的错误值

1 个答案: