ttyname man page

Prolog

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

ttyname, ttyname_r — find the pathname of a terminal

Synopsis

#include <unistd.h>

char *ttyname(int fildes);
int ttyname_r(int fildes, char *name, size_t namesize);

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 application shall not modify the string returned. The returned pointer might be invalidated or the string content might be overwritten by a subsequent call to ttyname().

The ttyname() function need not be thread-safe.

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}.

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.

If successful, the ttyname_r() function shall return zero. Otherwise, an error number shall be returned to indicate the error.

Errors

The ttyname() function may fail if:

EBADF
The fildes argument is not a valid file descriptor.
ENOTTY
The file associated with the fildes argument is not a terminal.

The ttyname_r() function may fail if:

EBADF
The fildes argument is not a valid file descriptor.
ENOTTY
The file associated with the fildes argument is not a terminal.
ERANGE
The value of namesize is smaller than the length of the string to be returned including the terminating null character.

The following sections are informative.

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.

See Also

The Base Definitions volume of POSIX.1‐2008, <unistd.h>

Info

2013 IEEE/The Open Group POSIX Programmer's Manual