multithreading - Creating multiple threads in C: write pid, tid and return integer -

i must this:

write program main thread creates 3 other threads. each ot these threads (different main thread) shall write pid , tid , terminate returning integer number between 1 , 3 , different value returned other threads. main thread shall print in standard out pid , value returned each of other threads.

i think i'm doing right, except don't understand how should return integer numbers between 1 , 3

i've following code far:

#include <stdio.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <pthread.h> #define debug 0  // int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void*), void *arg);  // int pthread_join(pthread_t, void **value_ptr);  void *printid(void *arg){      int i;      unsigned long tid;     tid = *((unsigned long *) arg);                 printf("thread tid: %lu thread pid: %d \n", tid, getpid());  }  int main(int argc, char *argv[]) {      pthread_t id1, id2, id3;      pthread_create(&id1, null, printid, &id1);      pthread_create(&id2, null, printid, &id2);      pthread_create(&id3, null, printid, &id3);      pthread_join(id1, null);      pthread_join(id2, null);      pthread_join(id3, null);      printf("main thread pid: %d\n", getpid());      sleep(1);  } 

since threads in c can return void*. can allocate space int want return, read main, don’t forget free it.