ISATTY(3) Linux Programmer's Manual ISATTY(3)NAMEisatty - 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 VALUEisatty() 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 ALSOfstat(2), ttyname(3)COLOPHON
This page is part of release 3.15 of the Linux man-pages project. A
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be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-12-03 ISATTY(3)