Unsubscribes from the given array of topic filters and optionally receive an asynchronous notification when the unsubscribe completes.

IotMqttError_t IotMqtt_UnsubscribeAsync( IotMqttConnection_t mqttConnection,
                                         const IotMqttSubscription_t * pSubscriptionList,
                                         size_t subscriptionCount,
                                         uint32_t flags,
                                         const IotMqttCallbackInfo_t * pCallbackInfo,
                                         IotMqttOperation_t * const pUnsubscribeOperation );

This function sends an MQTT UNSUBSCRIBE packet to the server. An UNSUBSCRIBE packet removes registered topic filters from the server. After unsubscribing, the server will no longer send messages on these topic filters to the client.

Corresponding subscription callback functions are also removed from the MQTT connection. These subscription callback functions will be removed even if the MQTT UNSUBSCRIBE packet fails to send.

Parameters

[in]	mqttConnection	The MQTT connection used for the subscription.
[in]	pSubscriptionList	Pointer to the first element in the array of subscriptions.
[in]	subscriptionCount	The number of elements in pSubscriptionList.
[in]	flags	Flags which modify the behavior of this function. See MQTT Function Flags.
[in]	pCallbackInfo	Asynchronous notification of this function's completion (`NULL` to disable).
[out]	pUnsubscribeOperation	Set to a handle by which this operation may be referenced after this function returns. This reference is invalidated once the unsubscribe operation completes.

Returns

This function will return IOT_MQTT_STATUS_PENDING upon success.

Upon completion of the unsubscribe (either through an IotMqttCallbackInfo_t or IotMqtt_Wait), the status will be one of:

If this function fails before queuing an unsubscribe operation, it will return one of:

See also: IotMqtt_UnsubscribeSync for a blocking variant of this function.; IotMqtt_SubscribeAsync for the function that adds subscriptions.