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

#define PIPES	1
#define BUFLEN	65536

struct pp {
	int		pfd[2];
};

int main(int argc, char *argv[]) {
	unsigned int	i;
	unsigned int	len;
	int		wlen;
	struct pp	*pvet = calloc(PIPES, sizeof(struct pp));
	char		*buf = malloc(BUFLEN);

	if (argc != 2)
		exit(1);

	wlen = atoi(argv[1]);
	if (wlen <= 0 || wlen > BUFLEN)
		exit(2);

	for (i = 0; i < BUFLEN; i++)
		buf[i] = 'o';

	// Create.
	for (i = 0; i < PIPES; i++) {
		if (pipe(pvet[i].pfd) != 0) {
			perror("pipe");
			abort();
		}
	}

	// Fill pipes.
	for (i = 0; i < PIPES; i++) {
		fprintf(stderr, "Pipe: %05u/%d\n", i, PIPES);
		for (len = 0; len < BUFLEN; len += wlen) {
			fprintf(stderr, "\r  write: %05u..%u/%d", len,
					len+(unsigned)wlen, BUFLEN);
			if (write(pvet[i].pfd[1], &buf[len], wlen) <= 0) {
				perror("write");
				abort();
			}
		}
		fprintf(stderr, "\n");
	}

	// Consume data from pipes.
	for (i = 0; i < PIPES; i++) {
		fprintf(stderr, "Pipe: %05u/%d\n", i, PIPES);
		if (read(pvet[i].pfd[0], buf, BUFLEN) != BUFLEN) {
			perror("read");
			abort();
		}
	}

	exit(0);
}