[net.unix] Test for background process

jimmy@rlvd.UUCP (Jimmy Aitken) (01/14/85)

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

Ron Natalie <ron@BRL-TGR> (01/17/85)

Actually, you can't tell any of them.  Isatty only tells you whether
the file descriptor is a terminal or not, which has no correllation
to whether input has been redirected.

-Ron