#include "apue.h"intmain(void){	printf("fd 0: %s\n", isatty(0) ? "tty" : "not a tty");	printf("fd 1: %s\n", isatty(1) ? "tty" : "not a tty");	printf("fd 2: %s\n", isatty(2) ? "tty" : "not a tty");	exit(0);}