Manually release ComPtr

Question

I'm using ComPtr (Microsoft::WRL) to manage some DirectX11 resources. How can I manually release it?

The "ReleaseAndGetAddressOf" method if I understand correctly, only frees the pointer and not the resource itself (which is returned), and I'm not sure about the "Reset" method.

The only alternatives I could think of are manually calling the pointer destructor, or after obtaining the raw pointer from "ReleaseAndGetAddressOf" calling "Release" on that, which I would like to avoid.

Answer 1

The source code for WRL is provided, have a look at include/winrt/wrl/client.h. The embedded COM pointer (ptr_ member) is released by the InternalRelease() function. Making any of the following a way to release the pointer suitable candidates:

• the destructor. The reason to use ComPtr<>
• assigning nullptr
• using ReleaseAndGetAddressOf(), the long way around
• calling Reset()

So assigning nullptr or calling Reset() are a good fit, take your pick. Or don't use it at all if you just want to manage the interface pointer yourself, it certainly isn't required to use ComPtr.

Answer 2

You can assign a null pointer.