| Microsoft DirectX 9.0 |
The WaitForVerticalBlank method is used to help the caller synchronize itself with the vertical blank interval. Depending on the option set with dwFlags, WaitForVerticalBlank will 1) block until blank begins, 2) block until blank ends, or 3) trigger an event when the blank interval begins.
Syntax
HRESULT WaitForVerticalBlank(
DWORD dwFlags,
HANDLE hEvent
);
Parameters
dwFlags
Determines how to wait for the vertical blank. May be one of the following values.
| Value | Description |
| DDWAITVB_BLOCKBEGIN | Return when the vertical blank interval begins. |
| DDWAITVB_BLOCKBEGINEVENT | Set up an event to trigger when the vertical blank begins. Not currently supported. |
| DDWAITVB_BLOCKEND | Return when the vertical blank interval ends and display begins. |
hEvent
Handle for the event that should be triggered when the vertical blank begins.
Return Values
| Value | Description |
| DD_OK | The method succeeded. |
| DDERR_INVALIDOBJECT | DirectDraw received a pointer that was an invalid DirectDraw object. |
| DDERR_INVALIDPARAMS | One or more of the input parameters is invalid. |
| DDERR_WASSTILLDRAWING | Informs DirectDraw that the previous Blt which is transfering information to or from this Surface is incomplete. |
| DDERR_UNSUPPORTED | Action not supported. |
See Also