Constants

Defined constants of the MQTT library.

Libraries may #define constants in their headers with special meanings. This page describes the meanings and uses of any constants defined by the MQTT library. Related constants are shown in a single section on this page.

MQTT Initializers

Provides default values for the data types of the MQTT library.

#define IOT_MQTT_NETWORK_INFO_INITIALIZER     { .createNetworkConnection = true }

#define IOT_MQTT_SERIALIZER_INITIALIZER       { 0 }

#define IOT_MQTT_CONNECT_INFO_INITIALIZER     { .cleanSession = true }

#define IOT_MQTT_PUBLISH_INFO_INITIALIZER     { .qos = IOT_MQTT_QOS_0 }

#define IOT_MQTT_SUBSCRIPTION_INITIALIZER     { .qos = IOT_MQTT_QOS_0 }

#define IOT_MQTT_CALLBACK_INFO_INITIALIZER    { 0 }

#define IOT_MQTT_CONNECTION_INITIALIZER       NULL

#define IOT_MQTT_OPERATION_INITIALIZER        NULL

#define IOT_MQTT_PACKET_INFO_INITIALIZER      { .pRemainingData = NULL, remainingLength = 0, packetIdentifier = 0, .type = 0 }

All user-facing data types of the MQTT library should be initialized using one of the following.

Warning

Failing to initialize an MQTT data type with the appropriate initializer may result in undefined behavior!

Note

The initializers may change at any time in future versions, but their names will remain the same.

Example

IotMqttNetworkInfo_t networkInfo = IOT_MQTT_NETWORK_INFO_INITIALIZER;
IotMqttSerializer_t serializer = IOT_MQTT_SERIALIZER_INITIALIZER;
IotMqttConnectInfo_t connectInfo = IOT_MQTT_CONNECT_INFO_INITIALIZER;
IotMqttPublishInfo_t publishInfo = IOT_MQTT_PUBLISH_INFO_INITIALIZER;
IotMqttSubscription_t subscription = IOT_MQTT_SUBSCRIPTION_INITIALIZER;
IotMqttCallbackInfo_t callbackInfo = IOT_MQTT_CALLBACK_INFO_INITIALIZER;
IotMqttConnection_t connection = IOT_MQTT_CONNECTION_INITIALIZER;
IotMqttOperation_t operation = IOT_MQTT_OPERATION_INITIALIZER;

MQTT Function Flags

Flags that modify the behavior of MQTT library functions.

• IOT_MQTT_FLAG_WAITABLE
  Allows the use of IotMqtt_Wait for blocking until completion.
• IOT_MQTT_FLAG_CLEANUP_ONLY
  Causes IotMqtt_Disconnect to only free memory and not send an MQTT DISCONNECT packet.

Flags should be bitwise-ORed with each other to change the behavior of IotMqtt_SubscribeAsync, IotMqtt_UnsubscribeAsync, IotMqtt_PublishAsync, their blocking versions; or IotMqtt_Disconnect.

Note

The values of the flags may change at any time in future versions, but their names will remain the same. Additionally, flags that may be used together will be bitwise-exclusive of each other.