Automatically converting an A* into a B*
Posted
by Xavier Nodet
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Published on 2010-04-26T17:08:18Z
Indexed on
2010/04/26
17:23 UTC
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Hi,
Suppose I'm given a class A
. I would like to wrap pointers to it into a small class B
, some kind of smart pointer, with the constraint that a B*
is automatically converted to an A*
so that I don't need to rewrite the code that already uses A*
.
I would therefore want to modify B
so that the following compiles...
struct A {
void foo() {}
};
template <class K>
struct B {
B(K* k) : _k(k) {}
//operator K*() {return _k;}
//K* operator->() {return _k;}
private:
K* _k;
};
void doSomething(A*) {}
void test() {
A a;
A* pointer_to_a (&a);
B<A> b (pointer_to_a);
//b->foo(); // I don't need those two...
//doSomething(b);
B<A>* pointer_to_b (&b);
pointer_to_b->foo(); // 'foo' : is not a member of 'B<K>'
doSomething(pointer_to_b); // 'doSomething' : cannot convert parameter 1 from 'B<K> *' to 'A *'
}
Note that B
inheriting from A
is not an option (instances of A
are created in factories out of my control)...
Is it possible?
Thanks.
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