// test pthread_create() and sched_yield()
//
#include <stdio.h>
#include <pthread.h>
#include <unistd.h> // for sleep()
#include <sched.h> // for sched_yield()

#define NT 4 // number of threads

int count[NT] = { 5, 4, 3, 2 };

void *f( void *v)
{
  int *p = v;

  while( *p > 0) { sleep(1); --*p; } // slowly decrement my counter

  return 0;
}

int main( void)
{
  pthread_t t[NT];

 // create the threads
 //
  for( int i = 0; i < NT; ++i)
    if( pthread_create( &t[i], 0, f, &count[i]) ) { perror( "pthread_create"); return 1; }

 // wait
 //
  while(1)
  {
    int done = 0; for( int i = 0; i < NT; ++i) if( count[i] == 0) ++done;

    // if( done == NT) break; // wait until all threads are finished

    if( done > 0) break; // wait until any one thread is finished

    sched_yield();
  }

 // stop all threads
 //
  for( int i = 0; i < NT; ++i) pthread_cancel( t[i]);
}