TTYNAME(3)                     Library Routines                     TTYNAME(3)

NAME

       ttyname,  isatty,  ttyslot - get name of associated terminal (tty) from
       file descriptor

SYNOPSIS

       #include <unistd.h>

       char * ttyname (int fd);
       int isatty (int fd);
       int ttyslot (void);

DESCRIPTION

       These functions operate on the system  file  descriptors  for  terminal
       type  devices.  These  descriptors  are not related to the standard I/O
       FILE typedef, but refer to the special  device  named  .ttyxx  and  for
       which  an  entry  exists  in  the  initialization file /etc/ttys.  (See
       ttys(5).)

       The isatty function determines if the file descriptor fd  refers  to  a
       valid terminal type device.

       The  ttyname function gets the related device name of a file descriptor
       for which isatty is true

       The ttyslot function fetches the current process' control terminal num‐
       ber from the ttys(5) file entry.

RETURN VALUES

       The  ttyname function returns the null terminated name if the device is
       found and isatty is true; otherwise a NULL pointer is returned.

       The ttyslot function returns the unit number  of  the  device  file  if
       found; otherwise the value zero is returned.

FILES

SEE ALSO

       ioctl(2), ttys(5)

HISTORY

       A  isatty,  ttyname,  and  ttyslot  function appeared in Version 7 AT&T
       UNIX.

BUGS

       The ttyname function leaves its result in an internal static object and
       returns a pointer to that object. Subsequent calls to ttyname will mod‐
       ify the same object.



GNO                             29 January 1997                     TTYNAME(3)