Porting Managed C# code to Unmanaged C++ code - Threads, Registry classes

Question

I am porting managed code to unmanaged code. I have APIs in managed code from these below namespaces

using namespaces System::Threading::Tasks;
using namespaces System::Registry;

I have converted Registry APIs. I am facing problem in converting

// Managed Code
Task::Factory->StartNew(gcnew Action(this, &MymanagedClass::ManagedFn));

Please let me know how to proceed with the porting.