Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: ttyname() - question
Message-ID: <10893@smoke.BRL.MIL>
Date: 31 Aug 89 22:37:51 GMT
References: <99@lkbpyr.UUCP> <2613@incas.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 6

In article <2613@incas.UUCP> tbecker@incas.UUCP (Thomas Becker) writes:
>So I tried to call ttyname(NULL) within test(), and it worked!

Only by accident.  You should use NULL only as a null pointer constant.
For a file descriptor that's associated with the terminal, try 2 (in a
UNIX environment), or, more portably, fileno(stderr).