Question

Here’s my situation:

I have .NET wrapper-objects in a C++/CLI layer that hold pointers to unmanaged C++ objects. I’ve implemented the finalizer so that it deletes the unmanaged memory pointed to by the wrapper-object on garbage-collection and sets the pointer to null.

Here’s the problem:

I’m watching the finalizer for the .NET wrapper-object and it gets called twice and tries to delete the same memory twice, indicating that I have somehow created 2 .NET wrapper objects that go out-of-scope, and are garbage collected while I’m still expecting the wrapper object to be in scope (these wrapper objects are getting passed to a VB.NET application).

Here’s my question:

Is there anyway for me to check the handle value so that I can confirm where the wrapper objects are getting created (copied or whatever)? Currently I’m looking at the handle values (EG – 0x0014fe80), but I see 3 different values for when the object is created, added to a collection, and deleted. So I’m not sure if the GC is just moving stuff around and this is the same object, or if I’m actually seeing 3 different objects that reference the same unmanaged memory. I would like to resolve the duplicate object copies if possible, but I understand that I will probably want to implement some sort of smart pointer so that this doesn’t happen.

Thanks,
Ian

Answer 1

Take a look at this question
Here is an implementation of a scoped_ptr that is noncopyable and has an auto-release mechanism for unmanaged objects, by @Ben Voigt