Re: [boost] [Boost.DLL] Formal Review request

Subject: Re: [boost] [Boost.DLL] Formal Review request
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2014-10-04 07:56:22

On Saturday 04 October 2014 12:24:23 Niall Douglas wrote:
> On 4 Oct 2014 at 12:41, Andrey Semashev wrote:
> > 
> > We had a similar discussion already. IMO, the library in its core should
> > not rely on compiler specific features and should be implementable in
> > pure C++ and standard APIs. This ensures its portability. It doesn't
> > matter how many compilers implement the extension because there will
> > always be the one that doesn't.
> 
> Andrey, please list here three C++ compilers which had at least one
> version release in the past five years which doesn't provide a magic
> macro expanding out to the mangling of the enclosing function.

I don't have such a survey, but I suspect you can't guarantee that every 
compiler out there supports it either.

> > In any case, I don't think that mangled names are useful for other reasons
> > I mentioned.
> 
> With such support, the following:
> 
>     plugin = dll::import_variable_alias<my_plugin_api>(
>         lib_path / "my_plugin_sum",
>         "plugin",
>         dll::load_mode::append_decorations
>     );
> 
> can become:
> 
>     BOOST_DLL_IMPORT(
>         lib_path / "my_plugin_sum",
>         BOOST_DLL_AUTO_ALIAS(my_namespace::plugin),  // import a
> variable
>         BOOST_DLL_AUTO_ALIAS(my_namespace::function), // import a
> function
>         BOOST_DLL_AUTO_ALIAS(my_namespace::object), // import a class
> implementation
>         ...
>     )

I'm not sure how is that an improvement. Maybe I just missed the point of your 
example.

> For those very few compilers without sufficient support, I am sure a
> BOOST_DLL_EXPLICIT_ALIAS macro could let you manually specify the
> mangling for some imported symbol. This would be useful in any case
> for MSVC to inspect Mingw binaries or vice versa.

I don't mind if the library offers an optional functionality to obtain a 
mangled name of a symbol. But it should be exactly that - an optional feature, 
which is only supported on select compilers and works on certain platforms. In 
its core the library should still provide a platform-neutral user interface.