#include <pthread.h>
#include <errno.h>

int main()
{
	pthread_rwlock_t lk;
	pthread_rwlockattr_t lkattr;
	pthread_rwlockattr_t * attrs[2];
	int i = 0, j = 0;

	attrs[0] = NULL;
	attrs[1] = &lkattr;
	
	if (0 != pthread_rwlockattr_init(&lkattr)) 
	{
		printf("Failed to create lock attribute!\n");
		return 1;
	}	

	if (0 != pthread_rwlockattr_setpshared(&lkattr, PTHREAD_PROCESS_SHARED))
	{
		printf("Failed to set lock attribute property!\n");
	}
	else
		printf("Lock attribute property set successfully!\n");


	for (j=0;j<2;j++)
	{
		if (0 != pthread_rwlock_init(&lk,attrs[j])) 
		{
			printf("Failed to create lock!\n");
			return 1;
		}
		
		if (0 == pthread_rwlock_unlock(&lk)) // This should fail
		{
			printf("Unlocking of an unlocked lock succeeded when it should not have.\n");
		}
		if (j==0)
			printf("\nTrying 10 recursive RO locks with NULL (default) attributes ...\n",i);
		else
			printf("\nTrying 10 recursive RO locks with permissive custom attributes ...\n",i);
		
		for (i = 0; i < 10; i++)
		{
			if (0 != pthread_rwlock_rdlock(&lk))
			{
				printf("Lock recursion iteration %d failed!\n",i);
			}
			else
				printf("Lock recursion iteration %d succeeded!\n",i);
		}
		
		for (i = 0; i < 10; i++)
		{
			if (0 != pthread_rwlock_unlock(&lk))
			{
				printf("Unlock recursion iteration %d failed!\n",i);
			}
			else
				printf("Unlock recursion iteration %d succeeded!\n",i);
		}
		if (0 == pthread_rwlock_unlock(&lk)) // This should fail
		{
			printf("Unlocking of an unlocked lock succeeded when it should not have.\n");
		}
		
		pthread_rwlock_destroy(&lk);
	}
	return 0;
}