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

pthread_mutex_t the_mutex;
pthread_mutex_t another_mutex;

void *a_run(void* p){
	pthread_mutex_lock(&the_mutex);
	printf("a:  In critical section\n");
	sleep(8);
	pthread_mutex_unlock(&another_mutex);
	pthread_mutex_lock(&another_mutex);
	sleep(2);
	pthread_mutex_unlock(&the_mutex);
	printf("a:  Done with lock\n");
}

void *b_run(void* p){
	pthread_mutex_lock(&another_mutex);
	sleep(1);
	printf("b:  Ready to enter critical section\n");
	pthread_mutex_lock(&the_mutex);
	printf("b:  In critical section\n");
	sleep(5);
	pthread_mutex_unlock(&another_mutex);
	pthread_mutex_unlock(&the_mutex);
	printf("b:  Done now\n");

}

int main(){
	pthread_t a, b;
	pthread_mutex_init(&the_mutex, 0);
	pthread_mutex_init(&another_mutex, 0);
	pthread_create(&a, 0, a_run, 0);
	pthread_create(&b, 0, b_run, 0);
	pthread_join(a, 0);
	printf("a has joined\n");
	pthread_join(b, 0);
	printf("Both threads joined\n");
	return 0;
}