Checks to see if unsigned integers < 0

[Volker Lendecke]

On Mon, Jul 15, 2013 at 08:47:12AM -0400, simo wrote:
> On Mon, 2013-07-15 at 11:28 +0200, Volker Lendecke wrote:
> > On Fri, Jul 12, 2013 at 08:36:13PM +0200, Herwin Weststrate wrote:
> > > (Issues were found compiling with clang, so it's a kind of static
> > > code analysis)
> > > 
> > > A number of times some checks are run to see if an unsigned integer
> > > is smaller than zero. Of course this cannot be true, this patch
> > > removes these checks.
> > 
> > Question -- is it guaranteed by Posix that uid_t is unsigned?
> > 
> > Volker
> > 
> 
> All I can find about uids in Posix:
> 
>         3.430 User ID
>         A non-negative integer that is used to identify a system user.
>         When the identity of a user is associated with a process, a user
>         ID value is referred to as a real user ID, an effective user ID,
>         or a saved set-user-ID.
> 
> It says the id must be a non-negative integer. Granted it could be
> represented by a signed integer with the prohibition to use its negative
> values, but that is highly unlikely. It is more likely that all
> platforms simply typedef a unsigned int to uid_t

With this vague statement I am a bit reluctant to remove the
uid<0 checks just because the most popular platform has that
as an unsigned. Maybe we should #ifdef that somehow if it is
a real problem?

Volker

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