ISATTY
Section: Linux Programmer's Manual (3)
Updated: 2019-03-06
Page Index
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.
- ENOTTY
-
fd
refers to a file other than a terminal.
On some older kernels, some types of files
resulted in the error
EINVAL
in this case (which is a violation of POSIX, which specifies the error
ENOTTY).
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.
SEE ALSO
fstat(2),
ttyname(3)
COLOPHON
This page is part of release 5.10 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
https://www.kernel.org/doc/man-pages/.