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From: "Carey Evans" <carey DOT evans AT gmail DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: ctype<char> custom table lookup in C++
Date: 20 May 2005 14:11:40 -0700
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Hans-Bernhard Broeker wrote:
[...]
> I find it hard to believe the C++ would actually predefine the
> implemention of a given feature.  That's none of their business.

Here's the bit of the spec I quoted:

  http://www.cantrip.org/lib-locales.html#lib.facet.ctype.char.members

As far as I can tell, it's defined that way so that the table may be
customised in a subclass.  There's nothing that says that the table()
method has to return __dj_ctype_flags or the equivalent table by
default, though; it just has to return some variation that works when
the character is cast to unsigned char as an index.  In DJGPP's case,
this is __dj_ctype_flags + 1.

[...]
> Only if you misunderstand how that table is supposed to be
> constructed, in the case of DJGPP.  The C++ standard seems to have
> forgotten about the C specialty of passing EOF into a <ctype.h>
> library macro/function.

The C++ ctype classes don't support passing EOF; valid input values are
CHAR_MIN to CHAR_MAX, inclusive.

-- 
Carey Evans