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).
InterfaceAttributeValue
isatty() Thread safetyMT-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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO
SEE ALSO
COLOPHON