#include "sem.c"


doit(semkey)
key_t semkey;
{
	int semid,pid;

	pid=getpid();
	printf("before semaphore %d\n",pid);
	if((semid = initsem(semkey))==-1)
		perror("semaphore exists");
	else
		{
		printf("calling p(%d) for pid=%d\n",semid,pid);
		p(semid);
		printf("pid=%d in critical section\n",pid);
		printf("going to sleep %d\n",pid);
		sleep(10);
		printf("done sleep %d\n",pid);
		printf("pid=%d leaving critical section\n",pid);
		printf("calling v(%d) for pid=%d\n",semid,pid);
		v(semid);
		printf("after semaphore %d\n",pid);
		exit(0);
		}
}

main()
{
	key_t semkey = 0x200; /* changed key to 0x60 from
				0x200 -> allowed permission
				to semaphore, made semid=1
				instead of semid=0 
				reason in man semctl  */
	if(fork()==0)
		{
		printf("f1 got id %d",getpid());
		doit(semkey);
		}
	if(fork()==0)
		{
		printf("f2 got id %d",getpid());
		doit(semkey);
		}
	if(fork()==0)
		doit(semkey);

}