#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>

/* gcc ....  -lpthread */
#include <pthread.h>

#define CHILDREN 8

void * whattodo( void * arg );

int main()
{
 int i, rc;
 int * t;
 pthread_t tid[ CHILDREN ];

 /* Create threads */
 for ( i = 0 ; i < CHILDREN ; i++ )
 {
   t = (int *)malloc( sizeof( int ) );
   *t = 10 + ( rand() % 21 );   /* in range [10,30] */
   printf( "MAIN: Next thread will nap for %d seconds.\n", *t );

   rc = pthread_create( &tid[i], NULL, whattodo, t );
   if ( rc != 0 ) {
     perror( "Could not create the thread" );
   }
 }

 /* Wait for threads to terminate */
 for ( i = 0 ; i < CHILDREN ; i++ ) {
   pthread_join( tid[i], NULL );       /* BLOCKING */
 }

 printf( "MAIN: All threads accounted for.\n" );
 return 0;
}

void * whattodo( void * arg )
{
 int t = *(int *)arg;
 printf( "THREAD %d: I'm gonna nap for %d seconds.\n", pthread_self(), t );
 sleep( t );
 printf( "THREAD %d: I'm awake now.\n", pthread_self() );
 return NULL;
}