MQTTc_Subscribe

Owned by Former user (Deleted)
Last updated: Jan 26, 2021 by WES Admin
1 min read

Send a 'Subscribe' message to MQTT server.

Files

mqtt-c.h/mqtt-c.c

Prototype

void  MQTTc_Subscribe (       MQTTc_CONN  *p_conn,
                              MQTTc_MSG   *p_msg,
                       const  CPU_CHAR    *topic_str,
                              CPU_INT08U   req_qos,
                              MQTTc_ERR   *p_err);

Arguments

p_conn

Pointer to MQTTc Connection to use.

p_msg

Pointer to MQTTc Message object to use.

topic_str

String containing the topic at which to subscribe. Must stay valid until the message has been completely sent.

req_qos

Requested level of QoS for this subscription.

payload_str

String containing the payload to publish. Must stay valid until the message has been completely sent.

p_err

Pointer to variable that will receive the return error code from this function:

MQTTc_ERR_NONE

MQTTc_ERR_NOT_INIT

MQTTc_ERR_NULL_PTR

MQTTc_ERR_INVALID_ARG

MQTTc_ERR_INVALID_BUF_SIZE

MQTTc_ERR_FAIL

Returned Values

None.

Required Configuration

None.

Notes / Warnings

  • This function MUST be called after the µC/MQTT-client initialization has been completed.
  • Both the MQTTc_CONN object and the MQTTc_MSG object used MUST stay valid until the message has completed (callback has been called).