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TTYNAME(3P)                POSIX Programmer's Manual               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 descrip-
       tor 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 charac-
       ter 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 overwrit-
       ten 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 .

IEEE/The Open Group                  2003                          TTYNAME(3P)