The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.

NAME

ttyname, ttyname_r - find the pathname of a terminal

SYNOPSIS

#include <unistd.h>

char *ttyname(int
fildes);

[TSF] [Option Start] int ttyname_r(int fildes, char *name, size_t namesize); [Option End]

DESCRIPTION

The ttyname() function shall return a pointer to a string containing a null-terminated pathname of the terminal associated with file descriptor fildes. The return value may point to static data whose content is overwritten by each call.

The ttyname() function need not be reentrant. A function that is not required to be reentrant is not required to be thread-safe.

[TSF] [Option Start] The ttyname_r() function shall store the null-terminated pathname of the terminal associated with the file descriptor fildes in the character array referenced by name. The array is namesize characters long and should have space for the name and the terminating null character. The maximum length of the terminal name shall be {TTY_NAME_MAX}. [Option End]

RETURN VALUE

Upon successful completion, ttyname() shall return a pointer to a string. Otherwise, a null pointer shall be returned and errno set to indicate the error.

[TSF] [Option Start] If successful, the ttyname_r() function shall return zero. Otherwise, an error number shall be returned to indicate the error. [Option End]

ERRORS

The ttyname() function may fail if:

[EBADF]
The fildes argument is not a valid file descriptor.
[ENOTTY]
The fildes argument does not refer to a terminal.

The ttyname_r() function may fail if:

[EBADF]
[TSF] [Option Start] The fildes argument is not a valid file descriptor. [Option End]
[ENOTTY]
[TSF] [Option Start] The fildes argument does not refer to a terminal. [Option End]
[ERANGE]
[TSF] [Option Start] The value of namesize is smaller than the length of the string to be returned including the terminating null character. [Option End]

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

The term ``terminal'' is used instead of the historical term ``terminal device'' in order to avoid a reference to an undefined term.

The thread-safe version places the terminal name in a user-supplied buffer and returns a non-zero value if it fails. The non-thread-safe version may return the name in a static data area that may be overwritten by each call.

FUTURE DIRECTIONS

None.

SEE ALSO

The Base Definitions volume of IEEE Std 1003.1-2001, <unistd.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 5

The ttyname_r() function is included for alignment with the POSIX Threads Extension.

A note indicating that the ttyname() function need not be reentrant is added to the DESCRIPTION.

Issue 6

The ttyname_r() function is marked as part of the Thread-Safe Functions option.

The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:

End of informative text.

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