write
Description
write(
writes the message string mqttClient
,mqttTopic
,mqttMsg
)mqttMsg
to the topic
mqttTopic
from the connected client
mqttClient
.
write(
uses additional options specified by one or more name-value pair arguments.mqttClient
,mqttTopic
,mqttMsg
,Name=Value
)
Examples
Write Messages to an MQTT Topic
Create an MQTT client and write messages to a topic with various options.
Create an MQTT client connected to the Eclipse HiveMQ™ public broker and write a
message to the topic myTopic
.
mqttClient = mqttclient("tcp://broker.hivemq.com"); write(mqttClient,"myTopic","Hello World")
Write to the topic with QualityOfService 2.
write(mqttClient,"myTopic","High Service Message",QualityOfService=2)
Write a message to be retained by the broker.
write(mqttClient,"myTopic","Msg for new subscribers",Retain=true)
Input Arguments
mqttClient
— MQTT client
Client
object
MQTT client specified as an icomm.mqtt.Client
object, created with
the mqttclient
function.
Example: mqttClient = mqttclient()
Data Types: object
mqttTopic
— MQTT topic
string | char
MQTT topic to write message to, specified as a string or character vector.
Example: "trubits/mqTop48"
Data Types: string
| char
mqttMsg
— MQTT message to write to topic
string | char
MQTT message to write to the topic, specified as a string or character vector.
Example: "Hello World"
Data Types: char
| string
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Example: QualityOfService=1
QualityOfService
— Quality of Service (QoS)
0 (default) | 1 | 2
Quality of Service (QoS) for message delivery, specified as an integer value of
0
, 1
, or 2
:
0
— Messages delivered at most once, not more (default).1
— Messages delivered at least once, not less.2
— Messages delivered exactly once, not more or less.
Example: QualityOfService=1
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
Retain
— Specify whether broke retains message
false
(default) | true
Control whether the broker retains the message for any new subscriber to the
topic, specified as a logical false
(default) or
true
.
Example: Retain=true
Data Types: logical
Version History
Introduced in R2022a
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