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

QOpcUaHistoryReadResponse(QOpcUaHistoryReadResponseImpl *impl)
virtual ~QOpcUaHistoryReadResponse()
QList<QOpcUaHistoryData> data() const
bool hasMoreData() const
bool readMoreData()
bool releaseContinuationPoints()
QOpcUa::UaStatusCode serviceResult() const
QOpcUaHistoryReadResponse::State state() const

Signals

void readHistoryDataFinished(const QList<QOpcUaHistoryData> &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.

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

Member Type Documentation

enum class QOpcUaHistoryReadResponse::State

This enum specifies the state the response is in.

ConstantValue
QOpcUaHistoryReadResponse::State::Unknown0
QOpcUaHistoryReadResponse::State::Reading1
QOpcUaHistoryReadResponse::State::Finished2
QOpcUaHistoryReadResponse::State::MoreDataAvailable3
QOpcUaHistoryReadResponse::State::Error4

Member Function Documentation

QOpcUaHistoryReadResponse::QOpcUaHistoryReadResponse(QOpcUaHistoryReadResponseImpl *impl)

Default constructs an instance of QOpcUaHistoryReadResponse.

[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] 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.

[virtual] QOpcUaHistoryReadResponse::~QOpcUaHistoryReadResponse()

The destructor for QOpcUaHistoryReadResponse

QList<QOpcUaHistoryData> QOpcUaHistoryReadResponse::data() const

Returns a list which contains the requested historic data.

bool QOpcUaHistoryReadResponse::hasMoreData() const

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

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.

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