bsd man page for isatty

TTYNAM(3F)																TTYNAM(3F)

NAME
       ttynam, isatty - find name of a terminal port

SYNOPSIS
       character*(*) function ttynam (lunit)

       logical function isatty (lunit)

DESCRIPTION
       Ttynam returns a blank padded path name of the terminal device associated with logical unit lunit.

       Isatty returns .true.  if lunit is associated with a terminal device, .false.  otherwise.

FILES
       /dev/*
       /usr/lib/libU77.a

DIAGNOSTICS
       Ttynam returns an empty string (all blanks) if lunit is not associated with a terminal device in directory `/dev'.

4.2 Berkeley Distribution					   May 15, 1985 							TTYNAM(3F)