From owner-freebsd-current  Tue Jul  3 22:54:52 2001
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Date: Wed, 4 Jul 2001 01:54:18 -0400
From: David Hill <djhill@novagate.net>
To: Gregory Neil Shapiro <gshapiro@FreeBSD.ORG>
Cc: freebsd-current@FreeBSD.ORG
Subject: Re: system and (v)fork
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On Tue, 3 Jul 2001 22:50:18 -0700
Gregory Neil Shapiro <gshapiro@FreeBSD.ORG> wrote:

> 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().
> 

Ahh, understood.

Thanks for the quick response
- David

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