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 pathname
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.
- ENODEV
- File descriptor refers to a slave pseudoterminal device but the
corresponding pathname could not be found (see NOTES).
- ENOTTY
- File descriptor does not refer to a terminal device.
- ERANGE
- (ttyname_r()) buflen was too small to allow storing the
pathname.
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 |
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 ttyname_r()
on the file descriptor in the new mount namespace will cause these functions
to return NULL and set errno to ENODEV.
COLOPHON¶
This page is part of release 5.04 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/.
