Re: [PATCH 1/3] Apply obvious numerical cast for stupid C compilers.

From: Shawn Pearce <spearce@spearce.org>
Date: Nov 5, 2006, 07:18 UTC
Message-ID: <20061105071805.GA4506@spearce.org>
In-Reply-To: <7v3b8ywewj.fsf@assigned-by-dhcp.cox.net>

Junio C Hamano <junkio@cox.net> wrote:

Show 10 quoted lines

> "Shawn O. Pearce" <spearce@spearce.org> writes:
> 
> > At least one (older) version of the Solaris C compiler won't allow
> > 'unsigned long x = -1' without explicitly casting -1 to a type of
> > unsigned long.  As annoying as it may be to explicitly perform the
> > cast the compiler is right; -1 is not an unsigned value.
> 
> Is the compiler really _right_?  The usual integral promotion
> rules should apply if it claims to be a C compiler, I would
> think.

I'm rusty on my C; but I would expect an error if I tried to assign
a clearly negative value into an unsigned value, especially in a
case like this.  It could be compiler is wrong, but as a programmer
I'd want to know I wrote something stupid like that, because maybe
the variable should have been signed.  :-)

> But I think the code actually wants ULONG_MAX there.  Is that
> symbolic constant available at the point of offending
> initialization with the header files we already include, I
> wonder.

Yes, I agree. I almost changed it to ULONG_MAX but didn't since the original author felt -1 was the better choice here. *shrug*

For what its worth ULONG_MAX works on my Mac OS X system.

Tomorrow when I have access to that "broken" platform again I'll try ULONG_MAX and see if it compiles there.