QMqtt Namespace

Contains miscellaneous identifiers used throughout the Qt MQTT module. More...

Header:	#include <QMqtt>
qmake:	QT += mqtt
Since:	Qt 5.12

Types

enum class	MessageStatus { Unknown, Published, Acknowledged, Received, Released, Completed }
enum class	PayloadFormatIndicator { Unspecified, UTF8Encoded }
enum class	ReasonCode { Success, SubscriptionQoSLevel0, SubscriptionQoSLevel1, SubscriptionQoSLevel2, NoMatchingSubscriber, …, WildCardSubscriptionsNotSupported }

Detailed Description

Type Documentation

[since 5.12] enum class QMqtt::MessageStatus

This enum type specifies the available states of a message. Depending on the QoS and role of the client, different message statuses are expected.

Constant	Value	Description
QMqtt::MessageStatus::Unknown	0	The message status is unknown.
QMqtt::MessageStatus::Published	1	The client received a message for one of its subscriptions. This applies to QoS levels 1 and 2.
QMqtt::MessageStatus::Acknowledged	2	A message has been acknowledged. This applies to QoS 1 and states that the message handling has been finished from the client side.
QMqtt::MessageStatus::Received	3	A message has been received. This applies to QoS 2.
QMqtt::MessageStatus::Released	4	A message has been released. This applies to QoS 2. For a publisher the message handling has been finished.
QMqtt::MessageStatus::Completed	5	A message has been completed. This applies to QoS 2 and states that the message handling has been finished from the client side.

This enum was introduced or modified in Qt 5.12.

[since 5.12] enum class QMqtt::PayloadFormatIndicator

The payload format provides information on the content of a message. This can help other clients to handle the message faster.

Constant	Value	Description
QMqtt::PayloadFormatIndicator::Unspecified	0	The format is not specified.
QMqtt::PayloadFormatIndicator::UTF8Encoded	1	The payload of the message is formatted as UTF-8 Encoded Character Data.

This enum was introduced or modified in Qt 5.12.

[since 5.12] enum class QMqtt::ReasonCode

This enum type specifies the available error codes.

Constant	Value	Description
QMqtt::ReasonCode::Success	0	The specified action has succeeded.
QMqtt::ReasonCode::SubscriptionQoSLevel0	0	A subscription with QoS level 0 has been created.
QMqtt::ReasonCode::SubscriptionQoSLevel1	0x01	A subscription with QoS level 1 has been created.
QMqtt::ReasonCode::SubscriptionQoSLevel2	0x02	A subscription with QoS level 2 has been created.
QMqtt::ReasonCode::NoMatchingSubscriber	0x10	The message has been accepted by the server, but there are no subscribers to receive this message. A broker may send this reason code instead of Success.
QMqtt::ReasonCode::NoSubscriptionExisted (since Qt 5.15)	0x11	No matching Topic Filter is being used by the Client.
QMqtt::ReasonCode::ContinueAuthentication (since Qt 5.15)	0x18	Continue the authentication with another step.
QMqtt::ReasonCode::ReAuthenticate (since Qt 5.15)	0x19	Initiate a re-authentication.
QMqtt::ReasonCode::UnspecifiedError	0x80	An unspecified error occurred.
QMqtt::ReasonCode::MalformedPacket	0x81	The packet sent to the server is invalid.
QMqtt::ReasonCode::ProtocolError	0x82	A protocol error has occurred. In most cases, this will cause the server to disconnect the client.
QMqtt::ReasonCode::ImplementationSpecificError	0x83	The packet is valid, but the recipient rejects it.
QMqtt::ReasonCode::UnsupportedProtocolVersion	0x84	The requested protocol version is not supported by the server.
QMqtt::ReasonCode::InvalidClientId	0x85	The client ID is invalid.
QMqtt::ReasonCode::InvalidUserNameOrPassword	0x86	The username or password specified is invalid.
QMqtt::ReasonCode::NotAuthorized	0x87	The client is not authorized for the specified action.
QMqtt::ReasonCode::ServerNotAvailable	0x88	The server to connect to is not available.
QMqtt::ReasonCode::ServerBusy	0x89	The server to connect to is not available. The client is asked to try at a later time.
QMqtt::ReasonCode::ClientBanned	0x8A	The client has been banned from the server.
QMqtt::ReasonCode::InvalidAuthenticationMethod	0x8C	The authentication method specified is invalid.
QMqtt::ReasonCode::InvalidTopicFilter	0x8F	The topic filter specified is invalid.
QMqtt::ReasonCode::InvalidTopicName	0x90	The topic name specified is invalid.
QMqtt::ReasonCode::MessageIdInUse	0x91	The message ID used in the previous packet is already in use.
QMqtt::ReasonCode::MessageIdNotFound	0x92	The message ID used in the previous packet has not been found.
QMqtt::ReasonCode::PacketTooLarge	0x95	The packet received is too large. See also QMqttServerConnectionProperties::maximumPacketSize().
QMqtt::ReasonCode::QuotaExceeded	0x97	An administratively imposed limit has been exceeded.
QMqtt::ReasonCode::InvalidPayloadFormat	0x99	The payload format is invalid. See also QMqttPublishProperties::payloadFormatIndicator().
QMqtt::ReasonCode::RetainNotSupported	0x9A	The server does not support retained messages. See also QMqttServerConnectionProperties::retainAvailable().
QMqtt::ReasonCode::QoSNotSupported	0x9B	The QoS level requested is not supported. See also QMqttServerConnectionProperties::maximumQoS().
QMqtt::ReasonCode::UseAnotherServer	0x9C	The server the client tries to connect to is not available. See also QMqttServerConnectionProperties::serverReference().
QMqtt::ReasonCode::ServerMoved	0x9D	The server the client tries to connect to has moved to a new address. See also QMqttServerConnectionProperties::serverReference().
QMqtt::ReasonCode::SharedSubscriptionsNotSupported	0x9E	Shared subscriptions are not supported. See also QMqttServerConnectionProperties::sharedSubscriptionSupported().
QMqtt::ReasonCode::ExceededConnectionRate	0x9F	The connection rate limit has been exceeded.
QMqtt::ReasonCode::SubscriptionIdsNotSupported	0xA1	Subscription IDs are not supported. See also QMqttServerConnectionProperties::subscriptionIdentifierSupported().
QMqtt::ReasonCode::WildCardSubscriptionsNotSupported	0xA2	Subscriptions using wildcards are not supported by the server. See also QMqttServerConnectionProperties::wildcardSupported().

Not all values are available in every use case. Especially, some servers will reject a reason code not suited for a specific command. See below table to highlight expected reason codes for specific actions.

Reason Code	Connect Properties	Subscription Properties	Message Properties
Success	X	X	X
SubscriptionQoSLevel0		X
SubscriptionQoSLevel1		X
SubscriptionQoSLevel2		X
NoMatchingSubscriber			X
UnspecifiedError	X	X	X
MalformedPacket	X
ProtocolError	X
ImplementationSpecificError	X	X	X
UnsupportedProtocolVersion	X
InvalidClientId	X
InvalidUserNameOrPassword	X
NotAuthorized	X	X	X
ServerNotAvailable	X
ServerBusy	X
ClientBanned	X
InvalidAuthenticationMethod	X
InvalidTopicFilter		X
InvalidTopicName	X		X
MessageIdInUse		X	X
MessageIdNotFound			X
PacketTooLarge	X
QuotaExceeded	X	X	X
InvalidPayloadFormat	X		X
RetainNotSupported	X
QoSNotSupported	X
UseAnotherServer	X
ServerMoved	X
SharedSubscriptionsNotSupported		X
ExceededConnectionRate	X
SubscriptionIdsNotSupported		X
WildCardSubscriptionsNotSupported		X

This enum was introduced or modified in Qt 5.12.