How to use C++ standard smart pointers with Windows HANDLEs?

inspired by Alexander Drichel's solution, here is even shorter

std::unique_ptr< HANDLE, decltype(&CloseHandle) > uniqueHandle( nullptr, CloseHandle );

Works in MSVC 2010. Note that you need to specify '&' for the function name in decltype() to deduce a pointer-to-function type.

The question can be extended for COM IUnknown pointers - can CComPtr be replaced by any of the standard smart pointers?

Yes. You don't specialize std::default_deleter, you simply replace the deleter type.

struct COMDeleter {
    template<typename T> void operator()(T* ptr) {
        ptr->Release();
    }
};
unique_ptr<IUnknown, COMDeleter> ptr; // Works fine

The same principle applies to shared_ptr and indeed, to HANDLE.

Create a specific smart pointer class, won't take long. Don't abuse library classes. Handle semantics is quite different from that of a C++ pointer; for one thing, dereferencing a HANDLE makes no sense.

One more reason to use a custom smart handle class - NULL does not always mean an empty handle. Sometimes it's INVALID_HANDLE_VALUE, which is not the same (actually -1).