- Qt 6.10
- Qt Serial Bus
- C++ Classes
- QModbusReply
- Qt 6.10.2 Reference Documentation

# QModbusReply Class

The QModbusReply class contains the data for a request sent with a QModbusClient derived class. More...

Header: | `#include <QModbusReply>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS SerialBus)` `target_link_libraries(mytarget PRIVATE Qt6::SerialBus)`
qmake: | `QT += serialbus`

- List of all members, including inherited members

## Public Types

enum | ReplyType { Raw, Common, Broadcast }

## Public Functions

| QModbusReply(QModbusReply::ReplyType type, int serverAddress, QObject *parent = nullptr)
QModbusDevice::Error | error() const
QString | errorString() const
`(since 6.0)` QList<QModbusDevice::IntermediateError> | intermediateErrors() const
bool | isFinished() const
QModbusResponse | rawResult() const
QModbusDataUnit | result() const
int | serverAddress() const
QModbusReply::ReplyType | type() const

## Signals

void | errorOccurred(QModbusDevice::Error error)
void | finished()

## Detailed Description

## Member Type Documentation

### enum QModbusReply::ReplyType

This enum describes the possible reply type.

Constant | Value | Description
--- | --- | ---
`QModbusReply::Raw` | `0` | The reply originates from a raw Modbus request. See QModbusClient::sendRawRequest
`QModbusReply::Common` | `1` | The reply originates from a common read, write or read/write request. See QModbusClient::sendReadRequest, QModbusClient::sendWriteRequest and QModbusClient::sendReadWriteRequest
`QModbusReply::Broadcast` | `2` | The reply originates from a Modbus broadcast request. The serverAddress() will return `0` and the finished() signal will be emitted immediately.

## Member Function Documentation

### QModbusReply::QModbusReply(QModbusReply::ReplyType type, int serverAddress, QObject *parent = nullptr)

Constructs a QModbusReply object with a given type and the specified parent.

The reply will be sent to the Modbus client represented by serverAddress.

### QModbusDevice::Error QModbusReply::error() const

Returns the error state of this reply.

See also errorString() and errorOccurred().

### `[signal]` void QModbusReply::errorOccurred(QModbusDevice::Error error)

This signal is emitted when an error has been detected in the processing of this reply. The finished() signal will probably follow.

The error will be described by the error code error. If errorString is not empty it will contain a textual description of the error. In case of a QModbusDevice::ProtocolError the rawResult() function can be used to obtain the original Modbus exception response to get the exception code.

Note: Do not delete this reply object in the slot connected to this signal. Use deleteLater() instead.

See also error() and errorString().

### QString QModbusReply::errorString() const

Returns the textual representation of the error state of this reply.

If no error has occurred this will return an empty string. It is possible that an error occurred which has no associated textual representation, in which case this will also return an empty string.

See also error() and errorOccurred().

### `[signal]` void QModbusReply::finished()

This signal is emitted when the reply has finished processing. The reply may still have returned with an error.

After this signal is emitted, there will be no more updates to the reply's data.

Note: Do not delete the object in the slot connected to this signal. Use deleteLater().

You can also use isFinished() to check if a QNetworkReply has finished even before you receive the finished() signal.

See also isFinished() and error().

### `[since 6.0]` QList<QModbusDevice::IntermediateError> QModbusReply::intermediateErrors() const

Returns the list of intermediate errors that might have happened during the send-receive cycle of a Modbus request until the QModbusReply reports to be finished.

This function was introduced in Qt 6.0.

### bool QModbusReply::isFinished() const

Returns `true` when the reply has finished or was aborted.

See also finished() and error().

### QModbusResponse QModbusReply::rawResult() const

Returns the raw response of a Modbus request.

If the request has not finished then the returned QModbusResponse instance is invalid.

See also type() and result().

### QModbusDataUnit QModbusReply::result() const

Returns the preprocessed result of a Modbus request.

For read requests as well as combined read/write requests send via QModbusClient::sendReadWriteRequest() it contains the values read from the server instance.

If the request has not finished, has failed with an error or was a write request then the returned QModbusDataUnit instance is invalid.

Note: If the type() of the reply is QModbusReply::Broadcast, the return value will always be invalid. If the type() of the reply is QModbusReply::Raw, the return value might be invalid depending on the implementation of QModbusClient::processPrivateResponse().

See also type(), rawResult(), and QModbusClient::processPrivateResponse().

### int QModbusReply::serverAddress() const

Returns the server address that this reply object targets.

### QModbusReply::ReplyType QModbusReply::type() const

Returns the type of the reply.

Note: If the type of the reply is QModbusReply::Raw, the return value of result() will always be invalid.

See also result() and rawResult().