pthreads.c

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

void* run(void *arg) {
  printf("hello from %d!\n", *(int*)arg);
  pthread_exit(NULL);
}

int main() {
  int ids[4];
  pthread_t threads[4];

  for (int i = 0; i < 4; i++) {
    ids[i] = i;
    printf("create thread %d\n", i);
    threads[i] = pthread_create(&threads[i], NULL, run, (void*)&ids[i]);
  }

  void* status;
  for (int i = 0; i < 4; i++) {
    printf("waiting for %d to join...\n", i);
    pthread_join(threads[i], &status);
    printf("thread %d joined with status %ld\n", i, (long)status);
  }

  pthread_exit(NULL);
  return 0;
}