This is used to when saving values to the Registry. It will create the specified subkey if it doesn't exist, or if the subkey already exists, it will open it.
xcall MIAMEX,MX'REGISTRY,2,hkey,subkey,rights,hkeynew,status
The parameters are nearly the same as for Open. The main difference is that the status parameter can return either of the following:
STATUS=1 (Key was created)
STATUS=2 (Key already existed and was opened)
