How do I get a thread ID from an arbitrary pthread_t?

Question

I have a pthread_t, and I\'d like to change its CPU affinity. The problem is that I\'m using glibc 2.3.2, which doesn\'t have pthread_setaffinity_np(). That\'s OK, though, b

Answer 1

Actually pthread_self returns pthread_t and not a integer thread id you can work with, the following helper function will get you that in a portable way across different POSIX systems.

uint64_t gettid() {
    pthread_t ptid = pthread_self();
    uint64_t threadId = 0;
    memcpy(&threadId, &ptid, std::min(sizeof(threadId), sizeof(ptid)));
    return threadId;
}