ISATTY(3) Linux Programmer's Manual ISATTY(3)
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 ter-
minal; 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.1-2001 speci-
fies the error ENOTTY for this case.
CONFORMING TO
SVr4, 4.3BSD, POSIX.1-2001.
SEE ALSO
fstat(2), ttyname(3)
COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-12-03 ISATTY(3)