MQTTAsync_willOptions - Man Page

Synopsis

#include <MQTTAsync.h>

Data Fields

char struct_id [4]
int struct_version
const char * topicName
const char * message
int retained
int qos
struct {
  int len
  const void * data
} payload

Detailed Description

MQTTAsync_willOptions defines the MQTT 'Last Will and Testament' (LWT) settings for the client. In the event that a client unexpectedly loses its connection to the server, the server publishes the LWT message to the LWT topic on behalf of the client. This allows other clients (subscribed to the LWT topic) to be made aware that the client has disconnected. To enable the LWT function for a specific client, a valid pointer to an MQTTAsync_willOptions structure is passed in the MQTTAsync_connectOptions structure used in the MQTTAsync_connect() call that connects the client to the server. The pointer to MQTTAsync_willOptions can be set to NULL if the LWT function is not required.

Field Documentation

char struct_id[4]

The eyecatcher for this structure. must be MQTW.

int struct_version

The version number of this structure. Must be 0 or 1 0 indicates no binary will message support

const char* topicName

The LWT topic to which the LWT message will be published.

const char* message

The LWT payload.

int retained

The retained flag for the LWT message (see MQTTAsync_message.retained).

int qos

The quality of service setting for the LWT message (see MQTTAsync_message.qos and Quality of service).

int len

binary payload length

const void* data

binary payload data

struct  { ... }  payload

The LWT payload in binary form. This is only checked and used if the message option is NULL

Author

Generated automatically by Doxygen for Paho Asynchronous MQTT C Client Library from the source code.

Info

Tue Sep 14 2021 Paho Asynchronous MQTT C Client Library