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From: donn@hp-dcd.UUCP
Newsgroups: net.unix-wizards
Subject: Re: What is the dup2() command ? - (nf)
Message-ID: <2532@hp-pcd.UUCP>
Date: Wed, 23-Nov-83 03:32:49 EST
Article-I.D.: hp-pcd.2532
Posted: Wed Nov 23 03:32:49 1983
Date-Received: Sat, 26-Nov-83 04:35:06 EST
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Organization: Hewlett-Packard, Fort Collins, CO
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#R:bpa:-19200:hp-dcd:3200004:000:408
hp-dcd!donn    Nov 16 09:42:00 1983

On dup2().

A emulation using fcntl and F_DUPFD was suggested, but it doesn't always
work.  If you read dup2() documentation carefully it does a dup to
*exactly* its argument, doing a close if necessary.  Fcntl does it to
the first available slot >= its argument.  Thus the suggested emulation
doesn't always work.  The emulation is:

	close(arg);
	fcntl(fd, F_DUPFD, arg);

Donn Terry
...hplabs!hp-dcd!donn