RE: [boost] Re: DLL library (Was: Re: additional boost libraries?)

From: Reece Dunn (msclrhd_at_[hidden])
Date: 2004-07-26 09:12:29

Vladimir Prus wrote:
>Reece Dunn wrote:
> > Would it be possible to have a mangle function, then you could do
> > something like:
> >
> >    static imported_function<void()>   apiFunc( mangle::mwcw( "ApiFunc" 
>),
> > "OSLib" );
> >
> > This would mean that imported_function need only know how to get the
> > function (e.g. using GetProcAddress in Win32) and not worry about the 
>name
> > mangling scheme used.
>
>I though more about a policy function/class. Something like:
>
>    boost::dll my_dll("foo", cpp_mangler);
>    boost::dll my_dll2("foo", c_mangler);

The problem with this is if you need different mangling schemes for the same 
library then you will have several instances of the same library loaded (not 
sure how Windows handles this). A possibility is to have the mangler 
specified in the constructor (defaulting to extern "C" functions) be the 
default mangler and have another function where you can explicitly state 
which mangler you need:

   boost::dll mylib( "mylib", gcc3_mangler );
   mylib.import< ... >( "get_id" ); // use GCC3 mangling
   mylib.import< ... >( "factorial", c_mangler ); // use extern "C" mangling

> > The name mangling could then be handled by a
> > mangler/demangler library that would be useful in diagnostics, e.g.:
> >
> >    template< typename T >
> >    inline void print_type( const T & t )
> >    {
> >       std::cout << demangle::gcc3( typeid(t).name());
> >    }
>
>That's for sure. And in other contexts too.

True. If you go for an external policy-based mangler like above then you 
don't need to worry about name mangler support (e.g. does the library have 
VC or GCC3 mangling?) immediately. You can provide a base set and add to 
that set later.

>I also wonder if it makes sense to sumbit just "dll" library, or some
>additional plugin support need to be developed first.

What sort of plugin support are you looking for? Do you mean something like 
COM/CORBA support or wrapper, e.g. something that can target both (and 
others like them) in one implementation?

Regards,
Reece

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