Random Chitchat 2012-2016

[xoft]

I'm having trouble with Linux's sem_timedwait() function. For some reason it returns a "timeout" immediately after being called with a 0.5sec timeout. Therefore the DeadlockDetect thread misfires on Linux.

Does anyone have any experience with this?

---

For those of you with Linux, can you compile and run this quick test program?

#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#include <semaphore.h>
#include <errno.h>

int main(void)
{
    sem_t sem;
    if (sem_init(&sem, 0, 0))
    {
        printf("sem_init failed\n");
        return 1;
    }
    timespec timeout;
    timeout.tv_sec = 1;
    timeout.tv_nsec = 500 * 1000 * 1000;
    clock_t Begin = clock();
    int res = sem_timedwait(&sem, &timeout);
    clock_t End = clock();
    printf("sem_timedwait: %d, errno %d, %llu ticks\n", res, errno, (long long)(End - Begin));
    sem_destroy(&sem);
    return 0;
}

Compile with (assuming test.cpp is the filename):

Code:

g++ test.cpp -lpthread

When run, it should print something like

Code:

sem_timedwait: -1, errno 110, 0 ticks

I'm interested in the results - are you getting zero ticks as well? Where's the bug?