#include <stdio.h>
#include <time.h>
#include <sys/types.h>
#include <unistd.h>

int main () {
	
	struct timespec ts1, ts2;
	pid_t newpid;
	int fd1[2], fd2[2];
	char m0[] = "\nabout to fork....\n";
	char m1[] = "message from parent to child\n";
	char m2[] = "message from child to parent\n";
	char m3[] = "\ndone....\n";
	char rbuf1[256];
	char rbuf2[256];
	int cn1, cn2;
	ts1.tv_sec = (time_t)1;
	ts1.tv_nsec = (long)1;
	ts2.tv_sec = (time_t)1;
	ts2.tv_nsec = (long)1;
	
	if ((pipe(fd1) == -1)) printf("error\n");
	if ((pipe(fd2) == -1)) printf("error\n");

	printf("fd1 %d %d fd2 %d %d\n", fd1[0], fd1[1], fd2[0], fd2[1]);
	if ((newpid = fork()) == -1) {
		printf("failed to fork\n\n");
		return 0;
	}
	if (newpid > 0) {			//parent ***************
		close(fd1[1]);	close(fd2[0]);	//closing 4 and 5
		dup(fd2[1]);	close(fd2[1]);	//taking 4 in place of 6

		write(4, m1, sizeof(m1));	//parent_to_child messg
		usleep(10000);
		cn1 = read(3, rbuf1, 256);
		write(1, rbuf1, cn1);
	} else {
		close(fd1[0]);	close(fd2[1]);	//closing 3 and 6
		dup(fd2[0]);	close(fd2[0]);	//taking 3 in place of 5

		write(4, m2, sizeof(m2));	//child_to_parent messg	
		usleep(10000);
		cn2 = read(3, rbuf2, 256);
		write(1, rbuf2, cn2);
	}

	write(2, m3, sizeof(m3));
	return 0;
}