GDI Event Services in Windows 2000

GDI Event Services describes a group of GDI event-related functions that a display driver can use for synchronization. While these event-related functions are documented as only available in Microsoft Windows XP and later, most of them are also available in Microsoft Windows 2000. Although most of these event-related functions are available in Windows 2000, using them in a driver implemented for Windows 2000 is discouraged because such a driver could make Windows 2000 unreliable.

The event-related functions that are available in Windows 2000 behave similarly in Windows 2000 as they do in Windows XP except for the EngWaitForSingleObject function. The EngWaitForSingleObject implementation in Windows 2000 returns a DWORD value rather than the BOOL value that the Windows XP implementation returns. This DWORD value can be one of the following values:

Zero
Indicates that one of the following operations occurred:

• The wait succeeded. That is, the specified event object was set to the signaled state. The thread that called EngWaitForSingleObject can resume processing.

• The calling thread passed an invalid event-object pointer to the pEvent parameter of EngWaitForSingleObject.

Any nonzero value
This value is an NTSTATUS status value that indicates the specific error condition. For example, STATUS_TIMEOUT indicates that a time-out occurred.

Note   The EngClearEvent and EngReadStateEvent functions are not available in Windows 2000.