Send command to change guest screen lock state
PRL_RESULT PrlVm_SSOSendEventLockState( PRL_HANDLE hVm, PRL_BOOL bLocked );
PrlApiDeprecated.h
PRL_RESULT . Possible values:
PRL_ERR_INVALID_ARG - invalid handle of VM
PRL_ERR_UNINITIALIZED - when Desktop object is not accessible
PRL_ERR_OUT_OF_MEMORY - when failed to allocate memory
PRL_ERR_SUCCESS - function completed successfully.