Re: [Boost-users] Conversions between shared_ptr<Base> and shared_ptr<Derived>

Joshua Little wrote: [...]

So I have something like this:

std::vector BaseVector;

void add(boost::shared_ptr<Base>& newOne) { BaseVector.push_back(newOne); }

and I call it like this usually : boost::shared_ptr<Derived> p(new Derived); add(p);

I thought that it would work just like using raw pointers (which was working) but I get a compile time error that : no matching function call to add(boost::shared_ptr<Derived>&) canadites are add(boost::shared_ptr<Base>&).. ect.

It should fail with raw pointers, too, unless your compiler is too permissive. The problem is that void add(boost::shared_ptr<Base>& newOne) takes a non-const reference to shared_ptr<Base>, so you need a shared_ptr<Base> to call it. Change it to void add(boost::shared_ptr<Base> const & newOne) and it should work. And, as a general rule, always use a reference to const when you don't intend to modify the argument.