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).

Interface	Attribute	Value
isatty()	Thread safety	M-Safe

 

STANDARDS

POSIX.-2008.  

HISTORY

POSIX.-2001, SVr4, 4.3BSD.  

SEE ALSO

fstat(2), ttyname(3)

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Index

NAME

LIBRARY

SYNOPSIS

DESCRIPTION

RETURN VALUE

ERRORS

ATTRIBUTES

STANDARDS

HISTORY

SEE ALSO