gistfile1.c

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

void *worker(void *data);

struct worker_data_t
{
	pthread_t thread_id;
	pthread_mutex_t mutex;
	pthread_cond_t cond;
	long id, data;
	int ready;
};

struct worker_data_t *workers_data;

int main(int argc, char **argv)
{
	int cpus = sysconf(_SC_NPROCESSORS_ONLN);
	if (cpus < 1)
		cpus = 1;
	
	workers_data = malloc(cpus * sizeof(struct worker_data_t));
	int ret_val[cpus];
	
	for (int i = 0; i < cpus; i++)
	{
		pthread_mutex_init(&workers_data[i].mutex, NULL);
		pthread_cond_init(&workers_data[i].cond, NULL);
		workers_data[i].id = i;
		workers_data[i].ready = 0;
	}
	
	for (int i = 0; i < cpus; i++)
		ret_val[i] = pthread_create(&workers_data[i].thread_id, NULL, worker, &workers_data[i]);

	pthread_mutex_lock(&workers_data[0].mutex);
	workers_data[0].ready = 1;
	pthread_cond_signal(&workers_data[0].cond);
	pthread_mutex_unlock(&workers_data[0].mutex);

	pthread_mutex_lock(&workers_data[0].mutex);
	while (&workers_data[0].ready != 0)
		pthread_cond_wait(&workers_data[0].cond, &workers_data[0].mutex);
	pthread_mutex_unlock(&workers_data[0].mutex);
	
	
	pthread_mutex_lock(&workers_data[0].mutex);
	workers_data[0].ready = 1;
	pthread_cond_signal(&workers_data[0].cond);
	pthread_mutex_unlock(&workers_data[0].mutex);

	pthread_mutex_lock(&workers_data[0].mutex);
	while (&workers_data[0].ready != 0)
		pthread_cond_wait(&workers_data[0].cond, &workers_data[0].mutex);
	pthread_mutex_unlock(&workers_data[0].mutex);	

	/*pthread_mutex_lock(&workers_data[0].mutex);
	pthread_cond_signal(&workers_data[0].cond);
	pthread_mutex_unlock(&workers_data[0].mutex);

	pthread_mutex_lock(&workers_data[0].mutex);
	pthread_cond_signal(&workers_data[0].cond);
	pthread_mutex_unlock(&workers_data[0].mutex);*/
	
	for (int i = 0; i < cpus; i++)
		pthread_join(workers_data[i].thread_id, NULL);
	
	return 0;
}

void *worker(void *data)
{
	struct worker_data_t d = *((struct worker_data_t*)(data));
	printf("Thread %d started\n", d.id);
	for (;;)
	{
		pthread_mutex_lock(&workers_data[d.id].mutex);
		while (workers_data[d.id].ready == 0)
			pthread_cond_wait(&workers_data[d.id].cond, &workers_data[d.id].mutex);
		printf("catch!\n");
		workers_data[d.id].ready = 0;
		pthread_mutex_unlock(&workers_data[d.id].mutex);

		pthread_mutex_lock(&workers_data[d.id].mutex);
		pthread_cond_signal(&workers_data[d.id].cond);
		pthread_mutex_unlock(&workers_data[d.id].mutex);
		/*pthread_mutex_lock(&workers_data[d.id].mutex);
		pthread_cond_wait(&workers_data[d.id].cond, &workers_data[d.id].mutex);
		printf("catch!\n");
		pthread_mutex_unlock(&workers_data[d.id].mutex);*/
	}
}