Re: [boost] [nowide] request for clarification

Subject: Re: [boost] [nowide] request for clarification
From: Andrzej Krzemienski (akrzemi1_at_[hidden])
Date: 2017-06-16 21:37:11

2017-06-16 22:10 GMT+02:00 Artyom Beilis via Boost <boost_at_[hidden]>:

> On Fri, Jun 16, 2017 at 6:12 PM, Andrzej Krzemienski via Boost
> <boost_at_[hidden]> wrote:
> > Hi Everyone,
> > I admit I am not quite familiar with the problem, but I understand that
> as
> > one of the features, nowide offers a replacement for std::fstream that
> can
> > be constructed with its string types. At the same time we have
> > boost::filesystem that offers its own replacement for std::fstream that
> can
> > be constructed with filesystem::path. Now, if I want to use
> > `filesystem::path`s in my program (to be able to tell just any string
> from
> > a filesystem path), can I still use the benefits of `nowide` library?
> >
>
> Yes of course. There is an integration between nowide and filesystem
> to make sure it considers narrow API to be UTF-8.
>
> Also note the nowide::fstream works on MinGW as well
> as filesystem.fstream calls std::fstream and only MSVC version
> has open(wchar_t const *).
>
>
> > Also, in the docs for nowide::ifstream, we read, "Same as
> > std::basic_ifstream<char> but accepts UTF-8 strings under Windows." What
> > about other systems? What does it accept on Linux? ascii?
> >
>
> Under Linux it accepts "char *" in whatever encoding it is considered.
> See: http://cppcms.com/files/nowide/html/index.html#qna
>
>
> > In documentation for `nowide::args`, we read, "args is a class that fixes
> > standard main() function arguments and changes them to UTF-8 under
> > Microsoft Windows."
> > Does it write to the input strings in-place? is it even legal in C++?
>
> It replaces values of argc and argv and points them to other location
> not modifying the original values.
>

Ok. It makes sense :)

>
> > It "fixes", which implies that otherwise the args are "broken". How are
> > args in function main() broken? (other than not being UTF-8)?
> >
>
> That main(argc,argv) receives parameters converted from native UTF-8
> internal API to current locale's codepage - generally not being able
> to represent the all the required charset (since Windows does not
> support UTF-8 as native locale)
>

But given that what main() receives is already broken (Windos already could
not handle a name containing letters from two code pages), how can you
recover from this loss of information?

Regards,
&rzej;