QOpcUaHistoryReadResponse Class

This class is used for requesting historical data and storing the results. More...

Header: #include <QOpcUaHistoryReadResponse>
CMake: find_package(Qt6 REQUIRED COMPONENTS OpcUa)
target_link_libraries(mytarget PRIVATE Qt6::OpcUa)
qmake: QT += opcua
Since: Qt 6.3
Inherits: QObject

Public Types

enum class State { Unknown, Reading, Finished, MoreDataAvailable, Error }

Public Functions

virtual ~QOpcUaHistoryReadResponse()
QList<QOpcUaHistoryData> data() const
(since 6.7) QList<QOpcUaHistoryEvent> events() const
bool hasMoreData() const
bool readMoreData()
bool releaseContinuationPoints()
QOpcUa::UaStatusCode serviceResult() const
QOpcUaHistoryReadResponse::State state() const


void readHistoryDataFinished(const QList<QOpcUaHistoryData> &results, QOpcUa::UaStatusCode serviceResult)
(since 6.7) void readHistoryEventsFinished(const QList<QOpcUaHistoryEvent> &results, QOpcUa::UaStatusCode serviceResult)
void stateChanged(QOpcUaHistoryReadResponse::State state)

Detailed Description

A historical data request to an OPC UA server can be specified by a QOpcUaHistoryReadRawRequest or QOpcUaHistoryReadEventRequest.

Objects of this class and the statuscode of the request are returned in the QOpcUaHistoryReadResponse::readHistoryDataFinished(const QList<QOpcUaHistoryData> &results, QOpcUa::UaStatusCode serviceResult) or QOpcUaHistoryReadResponse::readHistoryEventsFinished(const QList<QOpcUaHistoryEvent> &results, QOpcUa::UaStatusCode serviceResult) signal depending on the request type and contain the result of a request.

Member Type Documentation

enum class QOpcUaHistoryReadResponse::State

This enum specifies the state the response is in.


Member Function Documentation

[virtual noexcept] QOpcUaHistoryReadResponse::~QOpcUaHistoryReadResponse()

The destructor for QOpcUaHistoryReadResponse

QList<QOpcUaHistoryData> QOpcUaHistoryReadResponse::data() const

Returns a list which contains the requested historic data.

[since 6.7] QList<QOpcUaHistoryEvent> QOpcUaHistoryReadResponse::events() const

Returns a list of QOpcUaHistoryEvent containing a list of events for every node to read in the request.

This function was introduced in Qt 6.7.

bool QOpcUaHistoryReadResponse::hasMoreData() const

Returns true if there are more values available from the historic data request.

[signal] void QOpcUaHistoryReadResponse::readHistoryDataFinished(const QList<QOpcUaHistoryData> &results, QOpcUa::UaStatusCode serviceResult)

This signal is emitted when a historical data request is finished. It adds to results and sets serviceResult to indicate the state of the result.

See also data() and serviceResult().

[signal, since 6.7] void QOpcUaHistoryReadResponse::readHistoryEventsFinished(const QList<QOpcUaHistoryEvent> &results, QOpcUa::UaStatusCode serviceResult)

This signal is emitted when a historical event request is finished. The new history data and any previous data is returned in results and serviceResult indicates the state of the result.

This function was introduced in Qt 6.7.

See also events() and serviceResult().

bool QOpcUaHistoryReadResponse::readMoreData()

Returns true if a read request for more historic values is successfully dispatched.

bool QOpcUaHistoryReadResponse::releaseContinuationPoints()

Releases the continuation points and sets the request as finished. Returns true if the pending request has been successfully finished; otherwise returns false.

QOpcUa::UaStatusCode QOpcUaHistoryReadResponse::serviceResult() const

Returns the serviceresult of the historic data request.

QOpcUaHistoryReadResponse::State QOpcUaHistoryReadResponse::state() const

Returns the current state of historic data request.

[signal] void QOpcUaHistoryReadResponse::stateChanged(QOpcUaHistoryReadResponse::State state)

This signal is emitted when the of a historical data request is changed. It sets state to indicate the state of the change.

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