TTYNAME(3) Linux Programmer's Manual TTYNAME(3)NAME
ttyname, ttyname_r - return name of a terminal
SYNOPSIS
#include <unistd.h>
char *ttyname(int fd);
int ttyname_r(int fd, char *buf, size_t buflen);
DESCRIPTION
The function ttyname() returns a pointer to the null-terminated path‐
name of the terminal device that is open on the file descriptor fd, or
NULL on error (for example, if fd is not connected to a terminal). The
return value may point to static data, possibly overwritten by the next
call. The function ttyname_r() stores this pathname in the buffer buf
of length buflen.
RETURN VALUE
The function ttyname() returns a pointer to a pathname on success. On
error, NULL is returned, and errno is set appropriately. The function
ttyname_r() returns 0 on success, and an error number upon error.
ERRORS
EBADF Bad file descriptor.
ENOTTY File descriptor does not refer to a terminal device.
ERANGE (ttyname_r()) buflen was too small to allow storing the path‐
name.
ENODEV File descriptor refers to a slave pseudoterminal device but the
corresponding pathname could not be found (see NOTES).
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
┌────────────┬───────────────┬────────────────────────┐
│Interface │ Attribute │ Value │
├────────────┼───────────────┼────────────────────────┤
│ttyname() │ Thread safety │ MT-Unsafe race:ttyname │
├────────────┼───────────────┼────────────────────────┤
│ttyname_r() │ Thread safety │ MT-Safe │
└────────────┴───────────────┴────────────────────────┘
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, 4.2BSD.
NOTES
A process that keeps a file descriptor that refers to a pts(4) device
open when switching to another mount namespace that uses a different
/dev/ptmx instance may still accidentally find that a device path of
the same name for that file descriptor exists. However, this device
path refers to a different device and thus can't be used to access the
device that the file descriptor refers to. Calling ttyname() or tty‐
name_r() on the file descriptor in the new mount namespace will cause
these functions to return NULL and set errno to ENODEV.
SEE ALSOtty(1), fstat(2), ctermid(3), isatty(3), pts(4)COLOPHON
This page is part of release 4.14 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/.
Linux 2017-05-03 TTYNAME(3)
