pthread_cond_timedwait()

Question

void wait(int timeInMs)
{
    struct timespec timeToWait;
    timeToWait.tv_sec = 5;
    timeToWait.tv_nsec = timeInMs*1000;

    int rt;

    pthread_mutex_lock(&am         


        

Answer 1

Main reference: http://pubs.opengroup.org/onlinepubs/009695299/functions/pthread_cond_timedwait.html

FIX of the code of andrewrk above

I can confirm Adrian May that gettimeofday doesn't function correctly! The code behavior of andrewrk inside an infinite thread like this

static void * thread_infinite(void * unused) {
while (1) {
        // compute stuff
        mywait(5);
}

is unpredictable: it runs approximate 700 times more until it blocks!

The correct version of the code of andrewrk is:

pthread_mutex_t fakeMutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t fakeCond = PTHREAD_COND_INITIALIZER;

void mywait(int timeInS)
{
    struct timespec ts;
    struct timeval now;
    int rt = 0;

//    gettimeofday(&now,NULL); // DOES NOT FUNCTION CORRECTLY
//    timeToWait.tv_sec = now.tv_sec+5;
//    timeToWait.tv_nsec = (now.tv_usec+1000UL*timeInMs)*1000UL;

    clock_gettime(CLOCK_REALTIME, &ts);
    ts.tv_sec += timeInS;

    pthread_mutex_lock(&fakeMutex);

    do {
        rt = pthread_cond_timedwait(&fakeCond, &fakeMutex, &ts);
        }
    while (rt == 0);

    pthread_mutex_unlock(&fakeMutex);
}