#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <fcntl.h>
#include <pthread.h>

struct iter {
	int in, out;
};

static long counter;

static void * inc(void *arg)
{
	struct iter *iter = (struct iter *)arg;
	int buf;

	while (read(iter->in, &buf, sizeof(buf)) > 0) {
		buf++;
		counter = buf;
		write(iter->out, &buf, sizeof(buf));
	}

	close(iter->in);
	close(iter->out);
	return NULL;
}

int main(int argc, char *argv[])
{
	pthread_t t1, t2;
	int fds[4];

	pipe(fds);
	pipe(fds+2);

	struct iter iter1 = {
		.in = fds[0],
		.out = fds[3],
	};
	struct iter iter2 = {
		.in = fds[2],
		.out = fds[1],
	};

	pthread_create(&t1, NULL, inc, &iter1);
	pthread_create(&t2, NULL, inc, &iter2);

	write(iter1.out, &counter, sizeof(counter));
	sleep(1);
	pthread_cancel(t1);
	pthread_cancel(t2);

	printf("messages/sec: %lu\n", counter);
	printf("time for message: %luns\n", 1000000000 / counter);

	return 0;
}