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

int val=0;

pthread_mutex_t mutex1;

void* sakana(void* x){
int c=1000000;
	while(c--){
		pthread_mutex_lock( &mutex1 );
		val++;
		pthread_mutex_unlock( &mutex1 );
	}
}

void* tako(void* x){
int c=1000000;
	while(c--){
		pthread_mutex_lock( &mutex1 );
		val++;
		pthread_mutex_unlock( &mutex1 );
	}
}

main(){
pthread_t thre1, thre2;

	pthread_setconcurrency( 2 );
	pthread_mutex_init( &mutex1, NULL );
	pthread_create(&thre1, NULL, sakana, NULL);
	pthread_create(&thre2, NULL, tako, NULL);

	pthread_join(thre1, NULL);
	pthread_join(thre2, NULL);

	printf("val %d\n", val);

}