ISATTY

Section: Linux Programmer's Manual (3)
Updated: 2015-08-08
Index Return to Main Contents

NAME

isatty - test whether a file descriptor refers to a terminal

SYNOPSIS

#include <unistd.h>

int isatty(int fd);

DESCRIPTION

The isatty() function tests whether fd is an open file descriptor referring to a terminal.

RETURN VALUE

isatty() returns 1 if fd is an open file descriptor referring to a terminal; otherwise 0 is returned, and errno is set to indicate the error.

ERRORS

EBADF: fd is not a valid file descriptor.
EINVAL: fd refers to a file other than a terminal. POSIX.1 specifies the error ENOTTY for this case.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
isatty()	Thread safety	MT-Safe

CONFORMING TO

POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.

COLOPHON

This page is part of release 4.02 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man-pages/.