This function will remove a subscription from a MQTT server.
Input:
handle : INT
The handle to the MQTT connection.
topic : STRING
The topic of the subscription.
Returns: INT
0
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- Subscription is removed.
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1
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- Invalid handle.
|
2
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- Not connected to the MQTT server.
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3
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- Invalid parameter.
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Declaration:
FUNCTION mqttUnsubscribe : INT;
VAR_INPUT
handle : INT;
topic : STRING;
END_VAR;
Example:
INCLUDE rtcu.inc
VAR
mqtt : INT;
rc : INT;
END_VAR;
PROGRAM example;
BEGIN
...
rc := mqttUnsubscribe(handle := mqtt, topic := "RTCU/+/temperature");
DebugFmt(message := "Unsubscribed= \1", v1 := rc);
...
END;
END_PROGRAM;
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