#include "apue.h" int main(void) { char *name; if (isatty(0)) { name = ttyname(0); if (name == NULL) name = "undefined"; } else { name = "not a tty"; } printf("fd 0: %s\n", name); if (isatty(1)) { name = ttyname(1); if (name == NULL) name = "undefined"; } else { name = "not a tty"; } printf("fd 1: %s\n", name); if (isatty(2)) { name = ttyname(2); if (name == NULL) name = "undefined"; } else { name = "not a tty"; } printf("fd 2: %s\n", name); exit(0); }