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Subject: Re: [boost] Unicode and codecvt facets
From: Bo Persson (bop_at_[hidden])
Date: 2010-07-06 13:09:19

Mathias Gaunard wrote:
> Le 05/07/2010 18:48, Bo Persson wrote:
>> You can, but you should specialize on the third parameter, if you
>> want to treat chars differently than default.
>> A codecvt<char, char, my_state_t> could easily do any kind of
>> conversions you need.
> I don't particularly need state, what I would like is to be able to
> use the right character types rather than wide characters, which are
> implementation-specific.

You mean the implementation doesn't provide the right character types?

The third parameter is there so you can specialize the use of chars,
other that the default implementation's. The codecvt<char, char,
mbstate_t> does what is "standard" on the platform. If you want
something else, you need a codecvt<char, char, non_std_state_t>, even
if you don't use the state variable passed to your codecvt<>. The
standard codecvt<> doesn't use it either.

> Also it doesn't seem states other than mbstate_t can be used by
> filebufs.

It should work, but perhaps not the most tested part on a standard

The filebuf (basic_filebuf, that is) is templated on char and
std::char_traits<char>. Again, if you want something other that
default, you need basic_filebuf<char, non_std_char_traits<char>>.

With the current standard you only have char and wchar_t. You could
perhaps use some other int types as characters, but will then run into
problems like having no string literals available.

Bo Persson

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