Hi, I've come with a problem with g++ 4.1.1 and people at gcc-help said
they think it's a bug, so I'll forward my original email to this list.
Regards,
Rodolfo Lima
----- Forwarded message from Rodolfo Schulz de Lima <[EMAIL PROTECTED]> -----
> Date: Fri, 13 Oct 2006 14:05:27 -0300
> From: Rodolfo Schulz de Lima <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
> Subject: pointer to template member function
> User-Agent: Mutt/1.5.11
>
> Hi, I´ve come across the following code, which g++ refuses to compile:
>
> // ---
> struct A
> {
> void a() {}
> };
>
> struct B : A
> {
> template <class T> void b() {}
> };
>
> typedef void (A::* ptr)();
>
> int main()
> {
> ptr x = &A::a, //
> y = static_cast<ptr>(&B::b<int>); // g++ chokes here
> }
> // ---
>
> G++ says that
>
> error: invalid static_cast from type
> '<unresolved overloaded function type>' to type 'void (A::*)()'
>
> But if I make void b() a non-template class and modify the cast to
> static_cast<ptr>(&B::b) it compiles fine. If this is valid, why the
> template case isn't?
>
> I'd really say that either casts shouldn't be valid, because in the
> non-template case, I could do:
>
> A a;
> (a.*x)(); // fine, x points to a member of A, and we are using it with
> // an instance of A.
>
> (a.*y)(); // this will have unpredictable results if B::b relies on
> // a B's attribute, because we're using B::* with an A
> // instance. static_casts should be 'safe', aren't they?
>
> Fortunately, both cases fail when using the default cast without
> static_cast. In the template case, compilation fails with:
>
> error: no matches converting function 'b' to type 'void (struct A::*)()'
> error: candidates are: template<class T> void B::b()
>
> And in the non template case, compilation fails with:
>
> error: cannot convert 'void (B::*)()' to 'void (A::*)()' in
> initialization
>
>
> Thanks,
> Rodolfo Lima.
----- End forwarded message -----
