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From: jimmy@rlvd.UUCP (Jimmy Aitken)
Newsgroups: net.lang.c,net.unix
Subject: Test for background process
Message-ID: <233@rlvd.UUCP>
Date: Mon, 14-Jan-85 04:59:16 EST
Article-I.D.: rlvd.233
Posted: Mon Jan 14 04:59:16 1985
Date-Received: Fri, 18-Jan-85 03:23:56 EST
Reply-To: jimmy@rlvd.UUCP (Jimmy Aitken)
Organization: Atlas Lab, SERC, UK (+44 235 21900)
Lines: 11
Xref: watmath net.lang.c:3915 net.unix:3344

I am trying to detect uniquely when one of the following situations occurs
in a C program.  I have tried isatty(3) but cannot distinguish between a),
b), and c) below.  Any helpful pointers would be appreciated.


	a) The standard input has been re-directed in a foreground process
	b) The standard input has been re-directed in a background process
	c) No re-direction of standard input in a background process
	d) No re-direction of standard input in a foreground process