The IDirect3DExecuteBuffer::Unlock method releases the direct pointer to the commands in the execute buffer. This must be done prior to calling the IDirect3DDevice::Execute method for the buffer.
HRESULT Unlock();
 None.
If the method succeeds, the return value is D3D_OK.
If the method fails, the return value may be one of the following values:
| D3DERR_EXECUTE_NOT_LOCKED | 
| DDERR_INVALIDOBJECT | 
  Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in ddraw.h.
  Import Library: Use ddraw.lib.