MQTTAsync_willOptions(3)

NAME
MQTTAsync_willOptions

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

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