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Date: Fri, 16 Jan 2009 19:38:06 +0100
From: Stefan Farfeleder <stefan@fafoe.narf.at>
To: Nate Eldredge <neldredge@math.ucsd.edu>
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Cc: Thierry Herbelot <thierry.herbelot@free.fr>,
	Garrett Cooper <yanefbsd@gmail.com>,
	Christoph Mallon <christoph.mallon@gmx.de>, freebsd-hackers@freebsd.org
Subject: Re: Confused by segfault with legitimate call to strerror(3) on
	amd64 / sysctl (3) setting `odd' errno's
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On Fri, Jan 16, 2009 at 10:33:15AM -0800, Nate Eldredge wrote:
> Pop quiz: which of the following statements is correct?
> 
> #include <stdlib.h>
> #include <unistd.h>
> 
> execl("/bin/sh", "/bin/sh", 0);
> execl("/bin/sh", "/bin/sh", NULL);

None, as NULL is allowed to expand to 0.  You have to write

execl("/bin/sh", "/bin/sh", (char *)0);