Re: CVS commit: src/common/lib/libc/stdlib

[David Laight <david%l8s.co.uk@localhost>]

On Tue, Apr 16, 2013 at 07:34:58PM +0000, Joerg Sonnenberger wrote:
> Module Name:  src
> Committed By: joerg
> Date:         Tue Apr 16 19:34:58 UTC 2013
> 
> Modified Files:
>       src/common/lib/libc/stdlib: _strtol.h _strtoul.h
> 
> Log Message:
> Do not use isalpha here, since we explicitly only support the Portable
> Character Set as base and in theory a locale could define a ASCII
> control character as letter, resulting in negations. Also avoid isdigit
> here to give the compiler a better chance of deciding whether an
> unsigned compare or a jump table is a better option, both are very
> likely better choices than the memory indirection.

There really ought to be a way of requesting the straight ASCII
versions of the isxxxx functions even after a local has been set.
A lot of code will use isalpha() to check for valid variable names (etc)
and really doesn't want locale-specific alpha characters be valid.
(Otherwise scripts become non-portable.)

OTOH (unsigned)(ch - '0') <= 9 is probably the fastest isdigit()
on any modern cpu.

        David

-- 
David Laight: david%l8s.co.uk@localhost