The SCM supports handle types to allow access to the following objects.
An SCManager object represents the database of installed services. It is a container object that holds service objects. The OpenSCManager function returns a handle to an SCManager object on a specified computer. This handle is used when installing, deleting, opening, and enumerating services and when locking the services database.
A service object represents an installed service. The CreateService and OpenService functions return handles to installed services.
The OpenSCManager, CreateService, and OpenService functions can request different types of access to SCManager and service objects. The requested access is granted or denied depending on the access token of the calling process and the security descriptor associated with the SCManager or service object.
The CloseServiceHandle function closes handles to SCManager and service objects. When you no longer need these handles, be sure to close them.
A lock object is created during SCM initialization to serialize access to the database of installed services. The SCM acquires the lock before starting a service or driver service. Service configuration programs use the LockServiceDatabase function to acquire the lock before reconfiguring a service and use the UnlockServiceDatabase function to release the lock.