Hi Michael, Thanks for the response. Your solution will indeed work, but the side effect is that spB and spC only have access to methods available in the base class. Imagine that B & C have unique methods that I want to access in main like. main() { A base; shPtrB spB(new B()); shPtrC spC(new C()); spB.PrintBrad(); // unique to B spC.PrintMichael(); // unique to C // this will fail obviously, but how else can I get access to unique methods in B & C base.AddChild(spB); base.AddChild(spC); } Thanks for your help Brad On 9/7/07, Michael Fawcett wrote:

On 9/7/07, Brad Ryder wrote:

...

main() { A base; shPtrB spB(new B()); shPtrC spC(new C());

// I dont want to typecast spB or spC

A.AddChild( (shPtrA) spB); A.AddChild( (shPtrA) spC); }

Simply stop using shPtrB and shPtrC, and just use shPtrA. e.g.,

main() { A base; shPtrA spB(new B()); shPtrA spC(new C());

// works fine A.AddChild(spB); A.AddChild(spC); }

HTH,

--Michael Fawcett _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

On 9/7/07, Michael Fawcett wrote:

On 9/7/07, Brad Ryder wrote:

...

Hi Michael,

Thanks for the response. Your solution will indeed work, but the side effect is that spB and spC only have access to methods available in the base class. Imagine that B & C have unique methods that I want to access in main like.

main() {

A base; shPtrB spB(new B()); shPtrC spC(new C());

spB.PrintBrad(); // unique to B spC.PrintMichael(); // unique to C

// this will fail obviously, but how else can I get access to unique methods in B & C base.AddChild(spB); base.AddChild(spC); }

Thanks for your help

Try to remember not to top-post.

Generally you should not need to know if the instances are indeed A, B, or C. If you did, why would you be storing them in a container of base class pointers?

If you find you really need to perform the cast, look at boost::static_pointer_cast.

--Michael Fawcett _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

Micheal, Sorry about the top post and thank you again for the response. I guess I really need to know how and if it's possible to make the base class A method void AddChild( shPtrA& child); accept shPtrA , shPtrB and shPtrC . You mentioned boost::static_pointer_cast. I will investigate. Thanks again. Brad

On 9/7/07, Peter Dimov wrote:

Brad Ryder:

...

...

typedef boost::shared_ptr<A> shPtrA; typedef boost::shared_ptr<B> shPtrB; typedef boost::shared_ptr<C> shPtrC;

class A {

void AddChild(shPtrA& child);

How about

void AddChild(shPtrA const& child);

? _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

Peter, Thanks for helping me out here. You can see in my previous post, I am still having difficulty. Brad