TTYNAME(3P)

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.

NAME
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 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.

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 fildes argument does not refer to a terminal.

The ttyname_r() function may fail if:

EBADF
    The fildes argument is not a valid file descriptor.

ENOTTY
    The fildes argument does not refer to 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.

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>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .