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isatty

Section: C Library Functions (3)
Updated: 202-0-17
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NAME

isatty - test whether a file descriptor refers to a terminal  

LIBRARY

Standard C library (libc,~-lc)  

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 safetyM-Safe
 

STANDARDS

POSIX.-2008.  

HISTORY

POSIX.-2001, SVr4, 4.3BSD.  

SEE ALSO

fstat(2), ttyname(3)

 

Index

NAME
LIBRARY
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
STANDARDS
HISTORY
SEE ALSO