/*
  join_self.c

  Shows that attempting to join with yourself results in a runtime
  error.  man page for pthread_join did no mention needing to include
  errno.h.
 */

#include <pthread.h> // pthread_t, pthread_create, pthread_join, pthread_self
#include <stdio.h>   // fprintf, stderr
#include <errno.h>   // EDEADLK

void *threadFunc(void *ignore) {
    int error;
    if ((error = pthread_join(pthread_self(), NULL)) == EDEADLK)
        fprintf(stderr, "Joining with your self is not possible\n");
    return NULL;
}

int main() {
    pthread_t tid;
    pthread_create(&tid, NULL, threadFunc, NULL);
    pthread_join(tid, NULL);
    return 0;
}