SubscribeActivityCoordinatorPolicy function (activitycoordinator.h)

Creates a subscription that delivers coordination notifications to the supplied callback based on the policy's configuration. Upon notification, the supplied callback is executed with the supplied context. A notification with the current state will be delivered immediately on a separate thread and may be delivered before this call returns. Changes made to the policy after subscribing do not affect the subscription. A single policy can be used to create many subscriptions with unique policy configurations. Notifications are serialized.

Syntax

HRESULT SubscribeActivityCoordinatorPolicy(
  ACTIVITY_COORDINATOR_POLICY       policy,
  ACTIVITY_COORDINATOR_CALLBACK     callback,
  void                              *callbackContext,
  ACTIVITY_COORDINATOR_SUBSCRIPTION *subscription
);

Parameters

policy

Supplies a handle to the target policy.

callback

Supplies the callback to be executed for all coordination notifications from this subscription.

callbackContext

Supplies the context to be passed to callback routine.

subscription

Supplies a pointer to an ACTIVITY_COORDINATOR_SUBSCRIPTION handle that receives the created subscription handle.

Return value

Returns an HRESULT.

Remarks

Note Do not perform your activity in this callback, since it will block delivery of future policy notifications for this subscription. This callback should be used to coordinate the starting and stopping of your activity in response to RUN/STOP notifications from the API.

Note Do not block this callback for extended periods of time, since it will block UnsubscribeActivityCoordinatorPolicy and may contribute to thread pool exhaustion.

Note Calls to UnsubscribeActivityCoordinatorPolicy from this callback will fail. Unsubscribing must occur outside the callback.

Requirements

See also

UnsubscribeActivityCoordinatorPolicy

ACTIVITY_COORDINATOR_CALLBACK

ACTIVITY_COORDINATOR_NOTIFICATION