线程同步

Question

我有一个有两个线程的进程，它是这样工作的

Thread1

while( true ){
    Time t = getTime();
    Notify/wakeup Thread2 after time 't'

    ....
    ....
}

Thread2

while( true ) {
     wait for a signal from Thread1

     do some stuff 
}

有没有办法实现这个场景？

PS:我正在使用Pthread库，也准备使用其他库了。

谢谢

Answer 1

使用usleep、条件变量和状态变量的组合：

pthread_cond_t cond;
pthread_mutex_t mutex;
int state = 0;

clock_t start, stop;    
while( true ){
    Time t = getTime();
    start = clock();
    // do some action
    stop = clock();

    if((stop - start) < t)
       usleep(t - (stop - start));

    pthread_mutex_lock(&mutex)
    state++;
    pthread_cond_signal(&cond);
    pthread_mutex_unlock(mutex);
}

然后在线程2中：

while( true ) {
     pthread_mutex_lock(&mutex);
     int st = state;
     while(state == st)
         pthread_cond_wait(&cond, &mutex);
     pthread_mutex_unlock(&mutex);

     do some stuff 
}