IotMqttCallbackInfo_t Struct Reference

Information on a user-provided MQTT callback function. More...

#include <iot_mqtt_types.h>

Data Fields
void *	pCallbackContext
	The first parameter to pass to the callback function to provide context.
void(*	function )(void *, IotMqttCallbackParam_t *)
	User-provided callback function signature. More...

Detailed Description

Information on a user-provided MQTT callback function.

Parameter for: IotMqtt_Subscribe, IotMqtt_Unsubscribe, and IotMqtt_Publish. Cannot be used with IOT_MQTT_FLAG_WAITABLE.

Provides a function to be invoked when an operation completes or when a server-to-client PUBLISH is received.

All instances of IotMqttCallbackInfo_t should be initialized with IOT_MQTT_CALLBACK_INFO_INITIALIZER.

Below is an example for receiving an asynchronous notification on operation completion. See IotMqtt_Subscribe for an example of using this struct with for incoming PUBLISH messages.

// Operation completion callback.
void operationComplete( void * pArgument, IotMqttCallbackParam_t * pOperation );

// Callback information.
IotMqttCallbackInfo_t callbackInfo = IOT_MQTT_CALLBACK_INFO_INITIALIZER;
callbackInfo.function = operationComplete;

// Operation to wait for.
IotMqttError_t result = IotMqtt_Publish( &mqttConnection,
                                         &publishInfo,
                                         0,
                                         &callbackInfo,
                                         &reference );

// Publish should have returned IOT_MQTT_STATUS_PENDING. Once a response
// is received, operationComplete is executed with the actual status passed
// in pOperation.

Field Documentation

function

void( * IotMqttCallbackInfo_t::function) (void *, IotMqttCallbackParam_t *)

User-provided callback function signature.

Parameters

[in]	void	* IotMqttCallbackInfo_t.pCallbackContext
[in]	IotMqttCallbackParam_t	* Details on the outcome of the MQTT operation or an incoming MQTT PUBLISH.

See also

IotMqttCallbackParam_t for more information on the second parameter.

---

The documentation for this struct was generated from the following file:

• iot_mqtt_types.h