Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.unix.questions
Subject: Re: isatty(stdin) usage
Keywords: isatty stdin terminal
Message-ID: <9686@smoke.BRL.MIL>
Date: 22 Feb 89 22:37:20 GMT
References: <314@wubios.wustl.edu>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 6

In article <314@wubios.wustl.edu> david@wubios.wustl.edu (David J. Camp) writes:
>          if (isatty (stdin))
>explain why it does not work?

Because you didn't RTFM.  Try
	if ( isatty( fileno( stdin ) ) )