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Date: Tue, 3 Jul 2001 22:50:18 -0700
From: Gregory Neil Shapiro <gshapiro@FreeBSD.ORG>
To: David Hill <djhill@novagate.net>
Cc: freebsd-current@FreeBSD.ORG
Subject: Re: system and (v)fork
In-Reply-To: <20010704014703.4ec62b5f.djhill@novagate.net>
References: <20010704014703.4ec62b5f.djhill@novagate.net>
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djhill> Reading Advanced Programming in the UNIX Environment by Richard
djhill> W. Stevens, I see that he says that vfork() should be used instead
djhill> of fork() when you just need to use one of the exec() functions,
djhill> since it doesn't need to fully copy the address space.

djhill> Later in the book, he has an example system() which uses fork() to
djhill> run /bin/sh -c via the execl() function.

djhill> Why wouldn't he use vfork() instead of fork()?

If there is anything that modifies memory or file descripts between the
fork() and exec*() call, you can't use vfork().

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