async-await - 如何使用 C++/COM 等待 IAsyncOperation

Question

我正在使用 C++ 和 COM 访问 WinRT API。

下面的代码给了我results == unspecified

ComPtr<IGeolocatorStatics> statics;
RoGetActivationFactory(HString::MakeReference(RuntimeClass_Windows_Devices_Geolocation_Geolocator).Get(), IID_PPV_ARGS(&statics));

ComPtr<IAsyncOperation<GeolocationAccessStatus>> op;
statics->RequestAccessAsync(&op);

GeolocationAccessStatus results;
op->GetResults(&results);

而我results == allowed是从添加Sleep电话中获得的。

ComPtr<IGeolocatorStatics> statics;
RoGetActivationFactory(HString::MakeReference(RuntimeClass_Windows_Devices_Geolocation_Geolocator).Get(), IID_PPV_ARGS(&statics));

ComPtr<IAsyncOperation<GeolocationAccessStatus>> op;
statics->RequestAccessAsync(&op);

Sleep(100);

GeolocationAccessStatus results;
op->GetResults(&results);

显然，我需要等待 AsyncOperation 以在完成时接收回调。我宁愿做前者。如何使用 COM 等待来自 C++ 的 WinRT IAsyncOperation？