main.c

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

pthread_t tid[2];
int counter;
pthread_mutex_t lock;

void* trythis(void* arg)
{
	pthread_mutex_lock(&lock);

	unsigned long i = 0;
	counter += 1;
	printf("\n Job %d has started\n", counter);

	for (i = 0; i < (0xFFFFFFFF); i++)
		;

	printf("\n Job %d has finished\n", counter);

	pthread_mutex_unlock(&lock);

	return NULL;
}

int main(void)
{
	int i = 0;
	int error;

	if (pthread_mutex_init(&lock, NULL) != 0) {
		printf("\n mutex init has failed\n");
		return 1;
	}

	while (i < 2) {
		error = pthread_create(&(tid[i]),
							NULL,
							&trythis, NULL);
		if (error != 0)
			printf("\nThread can't be created :[%s]",
				strerror(error));
		i++;
	}

	pthread_join(tid[0], NULL);
	pthread_join(tid[1], NULL);
	pthread_mutex_destroy(&lock);

	return 0;
}