#include <pthread.h>
#include <stdio.h>
#define NUM_THREADS 5
struct {
        pthread_mutex_t mutex; /* protexts access to value */
        int             value; /* Access protected by mutex */
} data = { PTHREAD_MUTEX_INITIALIZER, 0 };

void *thread( void *t_id ) {
        int i;
        for ( i = 0; i < 200; ++i ) {
                pthread_mutex_lock( &data.mutex );
                ++data.value;
                printf( "thread %d: data value = %d\n", t_id, data.value );
                pthread_mutex_unlock( &data.mutex );
        }
	pthread_exit( NULL );
}

int main() {
	pthread_t threads[ NUM_THREADS ];
	int rc, t;
	for ( t = 0; t < NUM_THREADS; t++ ) {
		printf( "Creating thread %d\n", t );
		pthread_create( &threads[ t ], NULL, thread, ( void * ) t );
	}
	pthread_exit( NULL );
}