AcxEventCreate function (acxevents.h)

Article
02/22/2024

The AcxEventCreate function creates an ACX event.

Syntax

NTSTATUS AcxEventCreate(
  ACXOBJECT              Object,
  PWDF_OBJECT_ATTRIBUTES Attributes,
  PACX_EVENT_CONFIG      Config,
  ACXEVENT               *Event
);

Parameters

Object

An ACXOBJECT that is described in Summary of ACX Objects.

Attributes

Additional Attributes defined using a WDF_OBJECT_ATTRIBUTES that are used to set the various object's values: cleanup and destroy callbacks, context type, and to specify its parent object.

Config

An ACX_EVENT_CONFIG structure that defines the ACX event configuration.

Event

The newly created ACXEVENT object (described in Summary of ACX Objects).

Return value

Returns STATUS_SUCCESS if the call was successful. Otherwise, it returns an appropriate error code. For more information, see Using NTSTATUS Values.

Remarks

An ACXEVENT represents an asynchronous notification available at the driver level. Events can be added to ACXCIRCUITs, ACXSTREAMs, ACXELEMENTs and ACXPINs. Internally they are exposed as KS Events to upper layers. For more information about KS Events, see KS Events.

Example

This example code snip, shows how ACX uses AcxEventCreate to create an audio jack change event.

    NTSTATUS status = STATUS_SUCCESS;
    
    PAGED_CODE();

    ACX_EVENT_CALLBACKS         eventCallbacks;
    ACX_EVENT_CONFIG            eventCfg;
    AFX_PIN_EVENT_CONTEXT       *eventCtx;
    ACXEVENT                    jackEvent;
    WDF_OBJECT_ATTRIBUTES       attributes;

    //
    // Add jack info change event to this jack object
    //
    ACX_EVENT_CALLBACKS_INIT(&eventCallbacks);
    eventCallbacks.EvtAcxEventEnable = &AfxPin::EvtJackEventEnableCallback;
    eventCallbacks.EvtAcxEventDisable = &AfxPin::EvtJackEventDisableCallback;

    ACX_EVENT_CONFIG_INIT(&eventCfg);
    eventCfg.Set = &KSEVENTSETID_PinCapsChange;
    eventCfg.Id = KSEVENT_PINCAPS_JACKINFOCHANGE;
    eventCfg.Callbacks = &eventCallbacks;

    WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE(&attributes, AFX_PIN_EVENT_CONTEXT);
    attributes.ParentObject = GetObjectHandle();
    status = AcxEventCreate(GetObjectHandle(), &attributes, &eventCfg, &jackEvent);

ACX requirements

Minimum ACX version: 1.0

For more information about ACX versions, see ACX version overview.

Requirements

Requirement	Value
Header	acxevents.h
IRQL	PASSIVE_LEVEL

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