Re: [Boost-users] [serialization] abstract templatized base class

Ruediger Berlich wrote:

...

From the documentation and the header file "is_abstract.hpp" it appears as if using the macro BOOST_IS_ABSTRACT would not work (indeed it produces lots of error messages) for templatized classes, but that I should instead add the following to the header:

In general, preprocessor macros don't work for templated classes. This is described in the manual.

namespace boost { namespace serialization { template<class T> struct is_abstract { typedef mpl::bool_<true> type; BOOST_STATIC_CONSTANT(bool, value = true); }; }}

Indeed this seems to work.

so one has to avoid the macro and drop down to the underlying source code. - just as you have done.

It appears to me as if another solution might be to use the original macro in those files where the templatized classes are first instantiated (i.e. "filled" with a type). Please note, though, that they are base-classes for some other non-abstract classes, so that I'm not sure this would work. Anyway, the idea would be something along the lines of

// [...] // myClass<myType> is no longer a template BOOST_IS_ABSTRACT(myClass<myType>)

class derived :public myClass<myType> { ...};

I believe that above would also work. Of course you have to do it for every "myType" so some of the convenience of the macro is lost but currently I see no other way. Robert Ramey