Re: [boost] [nowide] request for clarification

Subject: Re: [boost] [nowide] request for clarification
From: Peter Dimov (lists_at_[hidden])
Date: 2017-06-16 22:06:55

Niall Douglas wrote:
> > 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)
>
> This is incorrect. You have been able to set the Windows console to UTF-8 
> for many years. Just issue `chcp 65001`, your console is now in UTF-8 and 
> UTF-8 strings will present to argv.

You can set the console to UTF-8 and it will display UTF-8 correctly, but 
will UTF-8 strings come in (the narrow) argv? I think not.

#include <iostream>

int main( int argc, char const* argv[] )
{
    std::cout << argv[1] << std::endl;
}

C:\Users\Peter Dimov>chcp 65001
Active code page: 65001

C:\Projects\testbed2017>debug\testbed2017.exe проба
?????

Whereas:

#include <boost/nowide/args.hpp>
#include <iostream>

int main( int argc, char const* argv[] )
{
    boost::nowide::args args( argc, argv );
    std::cout << argv[1] << std::endl;
}

Oops, a compile error, Nowide doesn't take char const*. All right,

#include <boost/nowide/args.hpp>
#include <iostream>

int main( int argc, char * argv[] )
{
    boost::nowide::args args( argc, argv );
    std::cout << argv[1] << std::endl;
}

And now:

C:\Projects\testbed2017>debug\testbed2017.exe проба
����������

See? Much better. :-) Although there's still room for improvement:

#include <boost/nowide/args.hpp>
#include <boost/nowide/iostream.hpp>

int main( int argc, char* argv[] )
{
    boost::nowide::args args( argc, argv );
    boost::nowide::cout << argv[1] << std::endl;
}

C:\Projects\testbed2017>debug\testbed2017.exe проба
проба

Or alternatively,

#include <boost/nowide/args.hpp>
#include <cstdio>

int main( int argc, char* argv[] )
{
    boost::nowide::args args( argc, argv );
    std::puts( argv[1] );
}

with the same result.