Struct paho_mqtt_sys::MQTTAsync_message

#[repr(C)]pub struct MQTTAsync_message {
    pub struct_id: [c_char; 4],
    pub struct_version: c_int,
    pub payloadlen: c_int,
    pub payload: *mut c_void,
    pub qos: c_int,
    pub retained: c_int,
    pub dup: c_int,
    pub msgid: c_int,
    pub properties: MQTTProperties,
}

A structure representing the payload and attributes of an MQTT message. The message topic is not part of this structure (see MQTTAsync_publishMessage(), MQTTAsync_publish(), MQTTAsync_receive(), MQTTAsync_freeMessage() and MQTTAsync_messageArrived()).

Fields

struct_id: [c_char; 4]

The eyecatcher for this structure. must be MQTM.

struct_version: c_int

The version number of this structure. Must be 0 or 1. 0 indicates no message properties

payloadlen: c_int

The length of the MQTT message payload in bytes.

payload: *mut c_void

A pointer to the payload of the MQTT message.

qos: c_int

The quality of service (QoS) assigned to the message. There are three levels of QoS:

QoS0

Fire and forget - the message may not be delivered

QoS1

At least once - the message will be delivered, but may be delivered more than once in some circumstances.

QoS2

Once and one only - the message will be delivered exactly once.

retained: c_int

The retained flag serves two purposes depending on whether the message it is associated with is being published or received.

retained = true
For messages being published, a true setting indicates that the MQTT server should retain a copy of the message. The message will then be transmitted to new subscribers to a topic that matches the message topic. For subscribers registering a new subscription, the flag being true indicates that the received message is not a new one, but one that has been retained by the MQTT server.

retained = false
For publishers, this indicates that this message should not be retained by the MQTT server. For subscribers, a false setting indicates this is a normal message, received as a result of it being published to the server.

dup: c_int

The dup flag indicates whether or not this message is a duplicate. It is only meaningful when receiving QoS1 messages. When true, the client application should take appropriate action to deal with the duplicate message.

msgid: c_int

The message identifier is normally reserved for internal use by the MQTT client and server.

properties: MQTTProperties

The MQTT V5 properties associated with the message.

Trait Implementations

impl Clone for MQTTAsync_message

pub fn clone(&self) -> MQTTAsync_message

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for MQTTAsync_message

impl Debug for MQTTAsync_message

pub fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for MQTTAsync_message

pub fn default() -> MQTTAsync_message

Returns the "default value" for a type.