#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string.h>
#include <errno.h>

#define WARN(...) do { fprintf(stderr, __VA_ARGS__); fputc('\n', stderr); } while(0)
#define ERROR(...) do { WARN(__VA_ARGS__); exit(1); } while(0)

void nonblock(int fd, int nb)
{
	int flags = fcntl(fd, F_GETFL);
	flags &= ~O_NONBLOCK;
	if (nb)
		flags |= O_NONBLOCK;
	if (fcntl(fd, F_SETFL, flags) == -1)
		ERROR("failed: fcntl: %s", strerror(errno));
}

int main(void)
{
	int fd;
	int n;
	char buf[13];
	int i;
	fd = open("fifo", O_RDWR|O_NONBLOCK);
	WARN("opened %d", fd);
	nonblock(fd, 0);
	WARN("made blocking");
	for (i=0; i<20; ++i) {
		n = read(fd, buf, sizeof(buf));
		WARN("%d", n);
		buf[sizeof(buf)-1] = '\0';
		write(STDOUT_FILENO, buf, n);
	}
	WARN("read");
	close(fd);
	WARN("closed");
	return 0;
}