From: Mitchell Blank Jr <mitch@sfgoth.com>
Date: Sat, 19 Aug 2006 17:15:34 GMT
Subject: Re: [PATCH] Added support for dropping privileges to git-daemon.
Message-ID: <20060819171534.GA64962@gaz.sfgoth.com>
In-Reply-To: <e5bfff550608190819i3cade548g28b2c95fab172a49@mail.gmail.com>

Marco Costalba wrote:
> >> >+       if (!user ^ !group)
> >> >+               die("either set both user and group or none of them");
> 
> BTW the following (very ugly) works.
> 
>         if ((int)user ^ (int)group)

No it doesn't.  Besides being a dangerous cast (no guarantee that a pointer
will fit in an "int") your code is basically just a fancy way of saying

	if (user != group)

Which is definitely NOT what is intended.  "user" and "group" are pointers --
unless they're both NULL we expect them to have different values.  The
original code is equivalent to:

	if ((user == NULL) != (group == NULL))

which is what is actually intended.

-Mitch