MSDN documentation seems silent on whether RegCreateKeyEx ever updates the value of the handle referred to by its second-last parameter when it fails. My tests have only shown it not to update this - i.e., I set h = 0 before the call, pass &h to a call to RegCreateKeyEx to open a non-existent key, and see h = 0 after the call. Does anyone know of any situation in which the handle would be changed?