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

#define NLOOP 5000

int counter;

pthread_mutex_t counter_mutex = PTHREAD_MUTEX_INITIALIZER;

void *doit( void * );

int main(int argc, char **argv)
{
	pthread_t tidA, tidB;

	pthread_create( &tidA ,NULL, &doit, NULL );
	pthread_create( &tidB ,NULL, &doit, NULL );

	pthread_join( tidA, NULL );
	pthread_join( tidB, NULL );

	return 0;
}

void * doit( void * vptr)
{
	int i, val;

	for ( i=0; i<NLOOP; i++ ) {
		pthread_mutex_lock( &counter_mutex );
		val = counter++;
		printf("%x: %d \n", (unsigned int) pthread_self(), val + 1);
		counter = val + 1;
		pthread_mutex_unlock( &counter_mutex );
	}
	return NULL;
}