Re: [Boost-users] lexical_cast<unsigned char>: Compiler error

Subject: Re: [Boost-users] lexical_cast<unsigned char>: Compiler error
From: Ovanes Markarian (om_boost_at_[hidden])
Date: 2009-03-06 10:32:20

Hi!

strange code... You are trying to convert a 2 byte character string into a
single byte unsigned character value? Std C++ does not definitely provide
possibility for it. But if you know how to do the conversion, overload the
operator >>, which accepsts the istream and unsigned char, smth. similar to:

namespace your_namespace //define it in your namespace, but so that ADL
finds it
{
    std::istream& operator>>(std::istream& is, unsigned char& ch)
    {
       // read needed ammount of bytes from is (actually 1)
       ch=// convert it and assign to ch...
       return is;
    }
}

Try using wchar_t instead of unsigned char.

Regards,
Ovanes

On Fri, Mar 6, 2009 at 4:04 PM, Hansi <hansipet_at_[hidden]> wrote:

> Hello,
>
> I have a question. I need a lexical_cast for a BYTE. Now I get allways a
> compile error with VS2005 and VS2008:
>
> e.g.
>
>        unsigned char test = 2;
>
>        test = boost::lexical_cast<unsigned char>(L"2");
>
> Error   2       error C2679: binary '>>' : no operator found which takes a
> right-hand operand of type 'unsigned char' (or there is no acceptable
> conversion)     D:\boost\boost_1_38_0\boost\lexical_cast.hpp    771
>
>
> What I do wrong? How I can solve this problem?
>
> Regards
> Hansjörg
>
>