isatty(3) [osf1 man page]

ttyname(3)						     Library Functions Manual							ttyname(3)

NAME

       ttyname, isatty, ttyname_r -  Get the name of a terminal

LIBRARY

       Standard C Library (libc.so, libc.a)

SYNOPSIS

       #include <unistd.h>

       char *ttyname(
	       int file-descriptor);

       int isatty(
	       int file-descriptor);

       int ttyname_r(
	       int file-descriptor,
	       char *buffer,
	       int len);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       ttyname_r(): POSIX.1c

       isatty(), ttyname():  XSH4.2

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

PARAMETERS

       Specifies an open file descriptor.  Points to a buffer in which the terminal name is stored.  Specifies the length of the buffer pointed to
       by the buffer parameter.

DESCRIPTION

       The ttyname() function gets the name of a terminal.  It returns a pointer to a string containing the null-terminated pathname of the termi-
       nal device associated with the file-descriptor parameter.

       The isatty() function determines if the device associated with the file-descriptor parameter is a terminal.

NOTES

       The  ttyname()  function  returns a pointer to thread-specific data.  Subsequent calls to this function from the same thread overwrite this
       data.

RETURN VALUES

       Upon successful completion, the ttyname() function returns a pointer to a string identifying a terminal device.	A NULL pointer is returned
       if the file-descriptor parameter does not describe a terminal device in the /dev directory.

       Upon successful completion, the isatty() function returns a value of 1 if the specified file-descriptor parameter is associated with a ter-
       minal.  Otherwise, it returns a value of zero (0).

       [POSIX]	Upon successful completion, the ttyname_r() function stores the terminal name as a null-terminated string in the buffer pointed to
       by the buffer parameter and returns a value of 0 (zero).  Otherwise, it returns an error number.

       [Tru64  UNIX]  The  obsolete  version  of ttyname_r() functions the same way as the POSIX version, except it returns a -1 upon unsuccessful
       completion.

ERRORS

       If the isatty() function fails, errno may be set to the following value: The file associated with file-descriptor is not a terminal.

       If the ttyname_r() function fails, errno may be set to the following value: The buffer parameter is a null pointer or the len parameter was
       too short to store the string.

RELATED INFORMATION

       Functions: ttyslot(3)

       Standards: standards(5) delim off

																	ttyname(3)

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 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 func-
       tion 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 pathname.

       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
       ttyname_r() on the file descriptor in the new mount namespace will cause these functions to return NULL and set errno to ENODEV.

SEE ALSO

       tty(1), fstat(2), ctermid(3), isatty(3), pts(4)

COLOPHON

       This  page is part of release 4.15 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)