How do I safely pass a CComPtr<IDirect3DDevice9> to another class via its constructor? Do I pass by reference or by value? Which way does the CComPtr actually add to the reference counter? And do I store it as raw pointer or another CComPtr in the newly created class?

I'm bit overwhelmed by the pointers, references and memory leaks I have to deal with coming from C# :-/

Thanks for your help in advance,

Jordy

In the new class you want to store a CComPtr, not a raw pointer. Using a combination of raw pointers and CComPtrs defeats the purpose of using a CComPtr in the first place. A CComPtr will increment the reference count of the pointed to interface whenever that interface is passed to a CComPtr constructor or assignment operator. You can pass a CComPtr by value or reference, though pass by value is generally inefficient if you're just going to sink that value into another CComPtr.

So if this is my class:

class MyClass
{
private:
	CComPtr<IDirect3DDevice9> d3ddev;

public:
	MyClass(IDirect3DDevice9 * _d3ddev)
	{
		this->d3ddev = _d3ddev;
	} 
};

And I would create an instance of it like this:

CComPtr<IDirect3DDevice9> d3ddev;

InitDevice()
{
    // d3ddev gets inititialized here
}

SomeFunction()
{
    InitDevice();
    MyClass myclass1(d3ddev);
}

Then that would be fine?