.\" Copyright (c) 1995 Jim Van Zandt <jrv@vanzandt.mv.com>
.\"
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.\" Modified 2001-12-13, Martin Schulze <joey@infodrom.org>
.\" Added ttyname_r, aeb, 2002-07-20
.\"
.TH TTYNAME 3 2016-12-12 "Linux" "Linux Programmer's Manual"
.SH NAME
ttyname, ttyname_r \- return name of a terminal
.SH SYNOPSIS
.nf
.B #include <unistd.h>
.sp
.BI "char *ttyname(int " fd );

.BI "int ttyname_r(int " fd ", char *" buf ", size_t " buflen );
.fi
.SH DESCRIPTION
The function
.BR ttyname ()
returns a pointer to the null-terminated pathname of the terminal device
that is open on the file descriptor \fIfd\fP, or NULL on error
(for example, if \fIfd\fP is not connected to a terminal).
The return value may point to static data, possibly overwritten by the
next call.
The function
.BR ttyname_r ()
stores this pathname in the buffer
.I buf
of length
.IR buflen .
.SH RETURN VALUE
The function
.BR ttyname ()
returns a pointer to a pathname on success.
On error, NULL is returned, and
.I errno
is set appropriately.
The function
.BR ttyname_r ()
returns 0 on success, and an error number upon error.
.SH ERRORS
.TP
.B EBADF
Bad file descriptor.
.TP
.B ENOTTY
File descriptor does not refer to a terminal device.
.TP
.B ERANGE
.RB ( ttyname_r ())
.I buflen
was too small to allow storing the pathname.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR ttyname ()
T}	Thread safety	MT-Unsafe race:ttyname
T{
.BR ttyname_r ()
T}	Thread safety	MT-Safe
.TE
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008, 4.2BSD.
.SH SEE ALSO
.BR tty (1),
.BR fstat (2),
.BR ctermid (3),
.BR isatty (3)
.SH COLOPHON
This page is part of release 4.10 of the Linux
.I 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/.