IDirectDrawSurface5::Lock (Windows CE 5.0)
This method obtains a pointer to the surface memory.
HRESULT Lock(LPRECT lpDestRect, LPDDSURFACEDESC2 lpDDSurfaceDesc, DWORD dwFlags, HANDLE hEvent);
Parameters
- lpDestRect
Address of a RECT structure that identifies the region of surface that is being locked. If NULL, the entire surface will be locked. - lpDDSurfaceDesc
Address of a DDSURFACEDESC2 structure that will be filled with the relevant details about the surface. - dwFlags
The following table shows the possible flags.Flag Description DDLOCK_EVENT This flag is not implemented. Triggers the event when IDirectDrawSurface5::Lock can return the surface memory pointer requested.
This flag is set if an event handle is being passed to IDirectDrawSurface5::Lock.
If multiple locks of this type are placed on a surface, events are triggered in FIFO order.
DDLOCK_READONLY Indicates that the surface being locked will only be read. DDLOCK_SURFACEMEMORYPTR Indicates that a valid memory pointer to the top of the specified rectangle should be returned. If no rectangle is specified, a pointer to the top of the surface is returned. This is the default.
DDLOCK_WAIT If a lock cannot be obtained because a blit operation is in progress, the method retries until a lock is obtained or another error occurs, such as DDERR_SURFACEBUSY. DDLOCK_WRITEONLY Indicates that the surface being locked will be write-enabled. DDLOCK_NOSYSLOCK This flag is not supported in Windows CE. - hEvent
This parameter is not used and must be set to NULL.
Return Values
If the method succeeds, the return value is DD_OK.
If the method fails, the return value may be one of the following error values:
| DDERR_INVALIDOBJECT |
| DDERR_INVALIDPARAMS |
| DDERR_OUTOFMEMORY |
| DDERR_SURFACEBUSY |
| DDERR_SURFACELOST |
| DDERR_WASSTILLDRAWING |
Remarks
For more information on using this method, see Accessing Surface Memory Directly.
After retrieving a surface memory pointer, you can access the surface memory until a corresponding IDirectDrawSurface5::Unlock method is called. When the surface is unlocked, the pointer to the surface memory is invalid.
Do not call DirectDraw blit functions to blit from a locked region of a surface. If you do, the blit returns either DDERR_SURFACEBUSY or DDERR_LOCKEDSURFACES. Additionally, GDI blit functions will silently fail when used on a locked video memory surface.
Requirements
OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.
Header: Ddraw.h.
Link Library: Ddraw.lib.
See Also
IDirectDrawSurface5::Unlock | IDirectDrawSurface5::GetDC | IDirectDrawSurface5::ReleaseDC
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