#include "apue.h"#include <fcntl.h>intmain(void){	int i, n;	int fd[2];	if (pipe(fd) < 0)		err_sys("pipe error");	set_fl(fd[1], O_NONBLOCK);	/*	 * Write 1 byte at a time until pipe is full.	 */	for (n = 0; ; n++) {		if ((i = write(fd[1], "a", 1)) != 1) {			printf("write ret %d, ", i);			break;		}	}	printf("pipe capacity = %d\n", n);	exit(0);}