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
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.
SEE ALSO
fstat(2), ttyname(3)
COLOPHON
This page is part of release 4.09 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/.
Free and Open Source Software