Re: Throwing constructor for wrong type of objects

From:

Victor Bazarov <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Tue, 29 Sep 2009 11:32:31 -0400

Message-ID:

<h9t9af$hq$3@news.datemas.de>

Vladimir Jovic wrote:

Template example update:
/////////////////////////////
template< typename T >
class B
{
    public:
        virtual ~B()
        {
        }
};
template< typename T >
class C : public B< T >
{
    public:
        virtual ~C()
        {
        }
};
class A
{
    public:
        A(const B< int > &)
        {
        }
        template< typename T >
        A(T)
        {
            throw 111;
        }
        ~A()
        {
        }
};
int main()
{
    A a( C<int>() ); // doesn't throw

    B<int> *b = new C<int>;
    A e(*b); // doesn't throw

    C< int > c;
    A d(c); // throws
}
////////////////

This example really demonstrates a problem I am facing.

Which is what?

So, is there a way to create such a constructor that is going a take a
reference to a specific base type, and to throw for all other types?

You made three examples, all of different classes. Some have a
templated c-tor, others don't... Do you expect us to read your mind?
If you want help, write down (and post) the requirements. Don't make
use guess. Please.

V
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