Microsoft DirectX 9.0


The SetMasterClock method sets the DirectMusic master clock to a clock identified by a GUID obtained by using the IDirectMusic8::EnumMasterClock method. There is only one master clock for all DirectMusic applications.


HRESULT SetMasterClock(
  REFGUID rguidClock



Reference to (C++) or address of (C) the GUID that identifies the clock to set as the master clock for DirectMusic. This parameter must be a GUID returned by the IDirectMusic8::EnumMasterClock method.

Return Values

If the method succeeds, the return value is S_OK.

If it fails, the method can return DMUS_E_PORTS_OPEN.


If another running application is also using DirectMusic, it is not possible to change the master clock until that application is shut down.

Most applications do not need to call SetMasterClock. It should not be called unless there is a need to synchronize tightly with a hardware timer other than the system clock.


  Header: Declared in dmusicc.h.

See Also