Re: using and ambiguous call

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Wed, 9 Jan 2008 10:03:18 -0500

Message-ID:

<fm2nnm$i6l$1@news.datemas.de>

valoh@krautgames.de wrote:

is this legal c++ code?

template <typename BaseT> struct A

'BaseT' is a bad name. I would probably call it 'WrappedT'.

{
BaseT& this_() { return *static_cast<BaseT*>(this); }

This can have undefined behaviour if 'BaseT' isn't related to
'A<BaseT>', you realise that of course...

template <typename T> void Foo() { this_().Bar<T>(); }

It seems that you're missing the keyword 'template' here:

... { this_(). template Bar<T>(); }
.. ^^^^^^^^

but I can be wrong.

  template <typename T> void Bar() { }
  template <typename T> void Bar(i32) { }
};

struct B : public A<B>
{
  using A<B>::Bar;

  template <typename T> void Bar() { }
};
//..

B test; test.Foo<int>();

when using such a construction I got mixed results on various
compiler. Often I get an ambiguous call to overloaded function error
(A<B>::Bar() vs B::Bar()). Sometime it seem to make a difference when
using template member function or non-template member function.

If it is not legal, why not? Any ideas for good workarounds? I have
template member functions for which i want default implementations and
helpers/wrappers in the base class. Several directly from this base
class derived classes only implementing a subset of the default
implementation. Any ideas?

Try it with all those compilers after adding the keyword 'template',
although I am not sure how it should affect the outcome. It's just
a hunch.

V
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