Re: [OT] Re: 0xdeadbeef vs 0xdeadbeefL

[Gabriel Paubert]

On Thu, Jul 08, 2004 at 12:15:21PM +0100, viro@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx wrote:
> On Thu, Jul 08, 2004 at 11:32:50AM +0200, Gabriel Paubert wrote:
> 
> > Yes, I know and I use BK. But given the fact that you insult me for 
> > better knowing C rules than you, I'm seriously considering switch 
> > to subversion or arch instead.
> > 
> > Argh, I've mentioned BK. There should be a Goldwin's law equivalent
> > for BitKeeper on lkml ;-)
> 
> Godwin, surely?

Right, should have looked the name up.

> 
> Anyway, if you think that suckversion authors knew C...  Try to read their
> decoder/parser/whatever you call the code handling the data stream obtained
> from other end of connection.  _Especially_ when it comes to signedness
> (of integers, mostly).

I did not read it, neither did I read BitKeeper's code for 
obvious reasons.

> 
> > - the aforementioned fgetc/getc/getchar issues.
> 
> ... have nothing to do with char; getc() has more legitimate return values
> than char can represent.  

Only one more, unless I missed something.

> No matter whether it's signed or unsigned, if
> you have
> 	... char c;
> 	...
> 	c = getc();
> you have a bug - Dirichlet Principle bites you anyway.

Indeed, but unfortunately you don't hit the problem with 
pure ASCII on x86. That's one of the reasons for which 
a lot of code ported to archs where char is unsigned by
default is simply compiled with -fsigned-char instead of 
correcting the bugs. 

The remaining case (char 0xff) is infrequent, at least 
for Latin-[19] encodings in the languages I know, and 
never happens with UTF-8 AFAICT. 

Heck, even the 2.4 ppc kernel is compiled with 
-fsigned-char, for $DEITY's sake. 

	Regards,
	Gabriel

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