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

/******************************************************************************
 * pthread_sleep takes an integer number of seconds to pause the current thread
 * We provide this function because one does not exist in the standard pthreads
 * library. We simply use a function that has a timeout.
 *
 *****************************************************************************/
int pthread_sleep (int seconds)
{
	pthread_mutex_t mutex;
	pthread_cond_t conditionvar;
	struct timespec timetoexpire;

	if(pthread_mutex_init(&mutex,NULL))
	{
		return -1;
	}
	if(pthread_cond_init(&conditionvar,NULL))
	{
		return -1;
	}

	//When to expire is an absolute time, so get the current time and add it
	//to our delay time
	timetoexpire.tv_sec = (unsigned int)time(NULL) + seconds;
	timetoexpire.tv_nsec = 0;

	return pthread_cond_timedwait(&conditionvar, &mutex, &timetoexpire);
}

/******************************************************************************
 * This is an example function that becomes a thread. It takes a pointer 
 * parameter so we could pass in an array or structure.
 *
 *****************************************************************************/
int *worker(void *arg)
{
	while(1)
	{
		printf("Thread Running\n");
		fflush(stdout);
		pthread_sleep(1);
	}
}

/******************************************************************************
 * The main function is just an infinite loop that spawns off a second thread
 * that also is an infinite loop. We should see two messages from the worker
 * for every one from main.
 *
 *****************************************************************************/
int main()
{
	pthread_t t_id;

	if ( -1 == pthread_create(&t_id, NULL, worker, NULL) )
	{
		perror("pthread_create");
		return -1;
	}

	while(1)
	{
		printf("Main Running\n");
		fflush(stdout);
		pthread_sleep(2);
	}

	return 0;
}