KsGenerateEvents function (ks.h)

Article
03/15/2022

The KsGenerateEvents function generates events of an indicated type that are present in Object's event list.

Syntax

void KsGenerateEvents(
  [in]           PVOID                      Object,
  [in, optional] const GUID                 *EventSet,
  [in]           ULONG                      EventId,
  [in]           ULONG                      DataSize,
  [in, optional] PVOID                      Data,
  [in, optional] PFNKSGENERATEEVENTCALLBACK CallBack,
  [in, optional] PVOID                      CallBackContext
);

Parameters

[in] Object

The object on which to generate events. This can be an AVStream filter or pin object.

[in, optional] EventSet

The event set GUID to match to determine which events to generate. If this parameter is NULL, set GUID is not taken into account for determining matching events.

[in] EventId

The event ID to match to determine which events to generate.

[in] DataSize

The size in bytes of the data with which to generate the data event.

[in, optional] Data

A pointer to a data buffer to include in the event notification. If the driver does not need to convey additional information via the notification, set this optional parameter to NULL.

[in, optional] CallBack

A pointer to a caller-specified function that is called to determine whether a given event should be generated. If this is NULL, no callback verification is performed to determine whether an event should be generated (only *EventSet *and EventId are used).

[in, optional] CallBackContext

A pointer to a caller-specified context that is passed to the callback function CallBack.

Return value

None

Remarks

When calling this function, a minidriver must place Data and CallBackContext in a locked, nonpageable data segment. In addition, note that the CallBack is made at DISPATCH_LEVEL. The callback function must be in a locked segment and must be prepared to run at IRQL = DISPATCH_LEVEL. Note that there is an additional issue in DX8 only: EventSet must be in a locked data segment.

Minidrivers typically do not call this function directly and instead use one of the versions that performs appropriate casting: KsFilterGenerateEvents or KsPinGenerateEvents.

An event is generated if it is present in *Object's *event list and *EventId *matches the event's ID, EventSet either matches the event's set GUID or is NULL, and *CallBack *is either NULL or authorizes the match.

CallBack is a caller-specified callback used for additional match determination. It is prototyped as follows:

BOOLEAN CallBack (IN PVOID Context, IN PKSEVENT_ENTRY EventEntry);

AVStream passes the contents of the KsGenerateEvents routine's parameter CallBackContext in this callback's Context parameter. EventEntry is a pointer to a KSEVENT_ENTRY structure that specifies the event that would be generated. The callback function should return TRUE if this event should be generated.

For more information, see Event Handling in AVStream and KS Events.

Requirements

Requirement	Value
Minimum supported client	Available in Microsoft Windows XP and later operating systems and DirectX 8.0 and later DirectX versions.
Target Platform	Universal
Header	ks.h (include Ks.h)
Library	Ks.lib
IRQL	<=DISPATCH_LEVEL