Re: [Boost-users] [Parameter] abstract base class

Subject: Re: [Boost-users] [Parameter] abstract base class
From: Noah Roberts (roberts.noah_at_[hidden])
Date: 2010-09-15 16:16:29

In article <4C911E60.70405_at_[hidden]>, 
watanabesj_at_[hidden] says...
> 
> AMDG
> 
> Noah Roberts wrote:
> > I don't really understand why this is going on.  Instead of just 
calling 
> > the base's constructor directly, the BOOST_PARAMETER_CONSTRUCTOR macro 
> > creates a type resolution instantiation with this:
> >
> > boost::parameter::aux::unaryfunptr_arg_type< void(*)(B) >::type
> >
> > 'B' being the base class.
> >
> > This explodes if B is an abstract class.  Both g++ 3.4.5 (mingw) and 
> > VS2010 hate this line.
> >
> > Before I go about attempting to devise a workaround, what is the purpose 
> > of this strange bit of code?  Why not just use 'B' directly??  The type 
> > resolution metafunction simply returns the 'B' place argument as its 
> > type anyway...
> >   
> 
> This bit of code exists to strip the parentheses off (B).

Of course.  OK.  And the parens are needed for templated base classes.

Thanks.

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