What is RIL_MQTT_QMTUNS

Dear Experts,
i am working with MC60 module and mqtt example, there is one function wriiten, but i don’t know what is the use of that
s32 RIL_MQTT_QMTUNS(u8 connectID, u8 msgId,u8* topic,u8* others)
{
s32 ret = RIL_AT_SUCCESS;
char strAT[200];

Ql_memset(strAT, 0, sizeof(strAT));
mqtt_param.prefix="+QMTUNS:";
mqtt_param.index = 2;
mqtt_param.data = 255;

if(NULL == others)
{
  Ql_sprintf(strAT, "AT+QMTUNS=%d,%d,\"%s\"\n", connectID,msgId,topic);
}
else
{
	
}
ret = Ql_RIL_SendATCmd(strAT,Ql_strlen(strAT),ATResponse_mqtt_handler,(void* )&mqtt_param,0);
SerialPrint("<-- Send AT:%s, ret = %d -->\r\n",strAT, ret);
if(RIL_AT_SUCCESS != ret)
{
    SerialPrint("\r\n<-- send AT command failure -->\r\n");
    return ret;
}
else if(0 != mqtt_param.data) 
{
    SerialPrint("\r\n<--MQTT subscribe failure, =%d -->\r\n", mqtt_param.data);
    return QL_RET_ERR_RIL_MQTT_FAIL;
}

return ret;

}

Hi Kan,

This fucntion is used to unsubscribe a topic to MQTT server by initiate AT command AT+QMTUNS.

Best Regards,