I have this problem with Qt whenever I try to set up a connection it never actually takes my data (e.g port name and baud rate) from the combo boxes and apparently it is because I do not link them very well. This is how I did it so far and, well, it doesn't work...
Any suggestions?
Secondary question: Am I adding the items to the combo box correctly?
Returns the serial number string of the serial port, if available; otherwise returns an empty string. Note: The serial number may include letters. This function was introduced in.
1 Answer
QComboBox::currentData() return the QVariant which you provided when adding the currently selected item into the widget. To get the user data from your combobox selection as your serial port baud rate, use
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/**************************************************************************** |
** |
** Copyright (C) 2011-2012 Denis Shienkov <denis.shienkov@gmail.com> |
** Copyright (C) 2011 Sergey Belyashov <Sergey.Belyashov@gmail.com> |
** Copyright (C) 2012 Laszlo Papp <lpapp@kde.org> |
** Copyright (C) 2012 Andre Hartmann <aha_1980@gmx.de> |
** Contact: https://www.qt.io/licensing/ |
** |
** This file is part of the QtSerialPort module of the Qt Toolkit. |
** |
** $QT_BEGIN_LICENSE:LGPL$ |
** Commercial License Usage |
** Licensees holding valid commercial Qt licenses may use this file in |
** accordance with the commercial license agreement provided with the |
** Software or, alternatively, in accordance with the terms contained in |
** a written agreement between you and The Qt Company. For licensing terms |
** and conditions see https://www.qt.io/terms-conditions. For further |
** information use the contact form at https://www.qt.io/contact-us. |
** |
** GNU Lesser General Public License Usage |
** Alternatively, this file may be used under the terms of the GNU Lesser |
** General Public License version 3 as published by the Free Software |
** Foundation and appearing in the file LICENSE.LGPL3 included in the |
** packaging of this file. Please review the following information to |
** ensure the GNU Lesser General Public License version 3 requirements |
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. |
** |
** GNU General Public License Usage |
** Alternatively, this file may be used under the terms of the GNU |
** General Public License version 2.0 or (at your option) the GNU General |
** Public license version 3 or any later version approved by the KDE Free |
** Qt Foundation. The licenses are as published by the Free Software |
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 |
** included in the packaging of this file. Please review the following |
** information to ensure the GNU General Public License requirements will |
** be met: https://www.gnu.org/licenses/gpl-2.0.html and |
** https://www.gnu.org/licenses/gpl-3.0.html. |
** |
** $QT_END_LICENSE$ |
** |
****************************************************************************/ |
#include'qserialport.h' |
#include'qserialportinfo.h' |
#include'qserialportinfo_p.h' |
#include'qserialport_p.h' |
#include<QtCore/qdebug.h> |
QT_BEGIN_NAMESPACE |
QSerialPortErrorInfo::QSerialPortErrorInfo(QSerialPort::SerialPortError newErrorCode, |
const QString &newErrorString) |
: errorCode(newErrorCode) |
, errorString(newErrorString) |
{ |
if (errorString.isNull()) { |
switch (errorCode) { |
case QSerialPort::NoError: |
errorString = QSerialPort::tr('No error'); |
break; |
case QSerialPort::OpenError: |
errorString = QSerialPort::tr('Device is already open'); |
break; |
case QSerialPort::NotOpenError: |
errorString = QSerialPort::tr('Device is not open'); |
break; |
case QSerialPort::TimeoutError: |
errorString = QSerialPort::tr('Operation timed out'); |
break; |
case QSerialPort::ReadError: |
errorString = QSerialPort::tr('Error reading from device'); |
break; |
case QSerialPort::WriteError: |
errorString = QSerialPort::tr('Error writing to device'); |
break; |
case QSerialPort::ResourceError: |
errorString = QSerialPort::tr('Device disappeared from the system'); |
break; |
default: |
// an empty string will be interpreted as 'Unknown error' |
// from the QIODevice::errorString() |
break; |
} |
} |
} |
QSerialPortPrivate::QSerialPortPrivate() |
#if defined(Q_OS_WIN32) |
: readChunkBuffer(QSERIALPORT_BUFFERSIZE, 0) |
#endif |
{ |
writeBufferChunkSize = QSERIALPORT_BUFFERSIZE; |
readBufferChunkSize = QSERIALPORT_BUFFERSIZE; |
} |
voidQSerialPortPrivate::setError(const QSerialPortErrorInfo &errorInfo) |
{ |
Q_Q(QSerialPort); |
error = errorInfo.errorCode; |
q->setErrorString(errorInfo.errorString); |
emit q->errorOccurred(error); |
emit q->error(error); |
} |
/*! |
class QSerialPort |
brief Provides functions to access serial ports. |
reentrant |
ingroup serialport-main |
inmodule QtSerialPort |
since 5.1 |
You can get information about the available serial ports using the |
QSerialPortInfo helper class, which allows an enumeration of all the serial |
ports in the system. This is useful to obtain the correct name of the |
serial port you want to use. You can pass an object |
of the helper class as an argument to the setPort() or setPortName() |
methods to assign the desired serial device. |
After setting the port, you can open it in read-only (r/o), write-only |
(w/o), or read-write (r/w) mode using the open() method. |
note The serial port is always opened with exclusive access |
(that is, no other process or thread can access an already opened serial port). |
Use the close() method to close the port and cancel the I/O operations. |
Having successfully opened, QSerialPort tries to determine the current |
configuration of the port and initializes itself. You can reconfigure the |
port to the desired setting using the setBaudRate(), setDataBits(), |
setParity(), setStopBits(), and setFlowControl() methods. |
There are a couple of properties to work with the pinout signals namely: |
QSerialPort::dataTerminalReady, QSerialPort::requestToSend. It is also |
possible to use the pinoutSignals() method to query the current pinout |
signals set. |
Once you know that the ports are ready to read or write, you can |
use the read() or write() methods. Alternatively the |
readLine() and readAll() convenience methods can also be invoked. |
If not all the data is read at once, the remaining data will |
be available for later as new incoming data is appended to the |
QSerialPort's internal read buffer. You can limit the size of the read |
buffer using setReadBufferSize(). |
QSerialPort provides a set of functions that suspend the |
calling thread until certain signals are emitted. These functions |
can be used to implement blocking serial ports: |
list |
li waitForReadyRead() blocks calls until new data is available for |
reading. |
li waitForBytesWritten() blocks calls until one payload of data has |
been written to the serial port. |
endlist |
See the following example: |
code |
int numRead = 0, numReadTotal = 0; |
char buffer[50]; |
for (;;) { |
numRead = serial.read(buffer, 50); |
// Do whatever with the array |
numReadTotal += numRead; |
if (numRead 0 && !serial.waitForReadyRead()) |
break; |
} |
endcode |
If l{QIODevice::}{waitForReadyRead()} returns c false, the |
connection has been closed or an error has occurred. |
If an error occurs at any point in time, QSerialPort will emit the |
errorOccurred() signal. You can also call error() to find the type of |
error that occurred last. |
Programming with a blocking serial port is radically different from |
programming with a non-blocking serial port. A blocking serial port |
does not require an event loop and typically leads to simpler code. |
However, in a GUI application, blocking serial port should only be |
used in non-GUI threads, to avoid freezing the user interface. |
For more details about these approaches, refer to the |
l {Qt Serial Port Examples}{example} applications. |
The QSerialPort class can also be used with QTextStream and QDataStream's |
stream operators (operator<<() and operator>>()). There is one issue to be |
aware of, though: make sure that enough data is available before attempting |
to read by using the operator>>() overloaded operator. |
sa QSerialPortInfo |
*/ |
/*! |
enum QSerialPort::Direction |
This enum describes the possible directions of the data transmission. |
note This enumeration is used for setting the baud rate of the device |
separately for each direction on some operating systems (for example, |
POSIX-like). |
value Input Input direction. |
value Output Output direction. |
value AllDirections Simultaneously in two directions. |
*/ |
/*! |
enum QSerialPort::BaudRate |
This enum describes the baud rate which the communication device operates |
with. |
note Only the most common standard baud rates are listed in this enum. |
value Baud1200 1200 baud. |
value Baud2400 2400 baud. |
value Baud4800 4800 baud. |
value Baud9600 9600 baud. |
value Baud19200 19200 baud. |
value Baud38400 38400 baud. |
value Baud57600 57600 baud. |
value Baud115200 115200 baud. |
value UnknownBaud Unknown baud. This value is obsolete. It is provided to |
keep old source code working. We strongly advise against |
using it in new code. |
sa QSerialPort::baudRate |
*/ |
/*! |
enum QSerialPort::DataBits |
This enum describes the number of data bits used. |
value Data5 The number of data bits in each character is 5. It |
is used for Baudot code. It generally only makes |
sense with older equipment such as teleprinters. |
value Data6 The number of data bits in each character is 6. It |
is rarely used. |
value Data7 The number of data bits in each character is 7. It |
is used for true ASCII. It generally only makes |
sense with older equipment such as teleprinters. |
value Data8 The number of data bits in each character is 8. It |
is used for most kinds of data, as this size matches |
the size of a byte. It is almost universally used in |
newer applications. |
value UnknownDataBits Unknown number of bits. This value is obsolete. It |
is provided to keep old source code working. We |
strongly advise against using it in new code. |
sa QSerialPort::dataBits |
*/ |
/*! |
enum QSerialPort::Parity |
This enum describes the parity scheme used. |
value NoParity No parity bit it sent. This is the most common |
parity setting. Error detection is handled by the |
communication protocol. |
value EvenParity The number of 1 bits in each character, including |
the parity bit, is always even. |
value OddParity The number of 1 bits in each character, including |
the parity bit, is always odd. It ensures that at |
least one state transition occurs in each character. |
value SpaceParity Space parity. The parity bit is sent in the space |
signal condition. It does not provide error |
detection information. |
value MarkParity Mark parity. The parity bit is always set to the |
mark signal condition (logical 1). It does not |
provide error detection information. |
value UnknownParity Unknown parity. This value is obsolete. It is |
provided to keep old source code working. We |
strongly advise against using it in new code. |
sa QSerialPort::parity |
*/ |
/*! |
enum QSerialPort::StopBits |
This enum describes the number of stop bits used. |
value OneStop 1 stop bit. |
value OneAndHalfStop 1.5 stop bits. This is only for the Windows platform. |
value TwoStop 2 stop bits. |
value UnknownStopBits Unknown number of stop bits. This value is obsolete. |
It is provided to keep old source code working. We |
strongly advise against using it in new code. |
sa QSerialPort::stopBits |
*/ |
/*! |
enum QSerialPort::FlowControl |
This enum describes the flow control used. |
value NoFlowControl No flow control. |
value HardwareControl Hardware flow control (RTS/CTS). |
value SoftwareControl Software flow control (XON/XOFF). |
value UnknownFlowControl Unknown flow control. This value is obsolete. It |
is provided to keep old source code working. We |
strongly advise against using it in new code. |
sa QSerialPort::flowControl |
*/ |
/*! |
enum QSerialPort::PinoutSignal |
This enum describes the possible RS-232 pinout signals. |
value NoSignal No line active |
value TransmittedDataSignal TxD (Transmitted Data). This value is |
obsolete. It is provided to keep old |
source code working. We strongly |
advise against using it in new code. |
value ReceivedDataSignal RxD (Received Data). This value is |
obsolete. It is provided to keep old |
source code working. We strongly |
advise against using it in new code. |
value DataTerminalReadySignal DTR (Data Terminal Ready). |
value DataCarrierDetectSignal DCD (Data Carrier Detect). |
value DataSetReadySignal DSR (Data Set Ready). |
value RingIndicatorSignal RNG (Ring Indicator). |
value RequestToSendSignal RTS (Request To Send). |
value ClearToSendSignal CTS (Clear To Send). |
value SecondaryTransmittedDataSignal STD (Secondary Transmitted Data). |
value SecondaryReceivedDataSignal SRD (Secondary Received Data). |
sa pinoutSignals(), QSerialPort::dataTerminalReady, |
QSerialPort::requestToSend |
*/ |
/*! |
enum QSerialPort::DataErrorPolicy |
obsolete |
This enum describes the policies for the received symbols |
while parity errors were detected. |
value SkipPolicy Skips the bad character. |
value PassZeroPolicy Replaces bad character with zero. |
value IgnorePolicy Ignores the error for a bad character. |
value StopReceivingPolicy Stops data reception on error. |
value UnknownPolicy Unknown policy. |
sa QSerialPort::dataErrorPolicy |
*/ |
/*! |
enum QSerialPort::SerialPortError |
This enum describes the errors that may be contained by the |
QSerialPort::error property. |
value NoError No error occurred. |
value DeviceNotFoundError An error occurred while attempting to |
open an non-existing device. |
value PermissionError An error occurred while attempting to |
open an already opened device by another |
process or a user not having enough permission |
and credentials to open. |
value OpenError An error occurred while attempting to open an |
already opened device in this object. |
value NotOpenError This error occurs when an operation is executed |
that can only be successfully performed if the |
device is open. This value was introduced in |
QtSerialPort 5.2. |
value ParityError Parity error detected by the hardware while |
reading data. This value is obsolete. We strongly |
advise against using it in new code. |
value FramingError Framing error detected by the hardware while |
reading data. This value is obsolete. We strongly |
advise against using it in new code. |
value BreakConditionError Break condition detected by the hardware on |
the input line. This value is obsolete. We strongly |
advise against using it in new code. |
value WriteError An I/O error occurred while writing the data. |
value ReadError An I/O error occurred while reading the data. |
value ResourceError An I/O error occurred when a resource becomes |
unavailable, e.g. when the device is |
unexpectedly removed from the system. |
value UnsupportedOperationError The requested device operation is not |
supported or prohibited by the running operating |
system. |
value TimeoutError A timeout error occurred. This value was |
introduced in QtSerialPort 5.2. |
value UnknownError An unidentified error occurred. |
sa QSerialPort::error |
*/ |
/*! |
Constructs a new serial port object with the given a parent. |
*/ |
QSerialPort::QSerialPort(QObject *parent) |
: QIODevice(*new QSerialPortPrivate, parent) |
, d_dummy(0) |
{ |
} |
/*! |
Constructs a new serial port object with the given a parent |
to represent the serial port with the specified a name. |
The name should have a specific format; see the setPort() method. |
*/ |
QSerialPort::QSerialPort(const QString &name, QObject *parent) |
: QIODevice(*new QSerialPortPrivate, parent) |
, d_dummy(0) |
{ |
setPortName(name); |
} |
/*! |
Constructs a new serial port object with the given a parent |
to represent the serial port with the specified helper class |
a serialPortInfo. |
*/ |
QSerialPort::QSerialPort(const QSerialPortInfo &serialPortInfo, QObject *parent) |
: QIODevice(*new QSerialPortPrivate, parent) |
, d_dummy(0) |
{ |
setPort(serialPortInfo); |
} |
/*! |
Closes the serial port, if necessary, and then destroys object. |
*/ |
QSerialPort::~QSerialPort() |
{ |
/**/ |
if (isOpen()) |
close(); |
} |
/*! |
Sets the a name of the serial port. |
The name of the serial port can be passed as either a short name or |
the long system location if necessary. |
sa portName(), QSerialPortInfo |
*/ |
voidQSerialPort::setPortName(const QString &name) |
{ |
Q_D(QSerialPort); |
d->systemLocation = QSerialPortInfoPrivate::portNameToSystemLocation(name); |
} |
/*! |
Sets the port stored in the serial port info instance a serialPortInfo. |
sa portName(), QSerialPortInfo |
*/ |
voidQSerialPort::setPort(const QSerialPortInfo &serialPortInfo) |
{ |
Q_D(QSerialPort); |
d->systemLocation = serialPortInfo.systemLocation(); |
} |
/*! |
Returns the name set by setPort() or passed to the QSerialPort constructor. |
This name is short, i.e. it is extracted and converted from the internal |
variable system location of the device. The conversion algorithm is |
platform specific: |
table |
header |
li Platform |
li Brief Description |
row |
li Windows |
li Removes the prefix '.' or '//./' from the system location |
and returns the remainder of the string. |
row |
li Unix, BSD |
li Removes the prefix '/dev/' from the system location |
and returns the remainder of the string. |
endtable |
sa setPort(), QSerialPortInfo::portName() |
*/ |
QString QSerialPort::portName() const |
{ |
Q_D(const QSerialPort); |
returnQSerialPortInfoPrivate::portNameFromSystemLocation(d->systemLocation); |
} |
/*! |
reimp |
Opens the serial port using OpenMode a mode, and then returns c true if |
successful; otherwise returns c false and sets an error code which can be |
obtained by calling the error() method. |
note The method returns c false if opening the port is successful, but could |
not set any of the port settings successfully. In that case, the port is |
closed automatically not to leave the port around with incorrect settings. |
warning The a mode has to be QIODevice::ReadOnly, QIODevice::WriteOnly, |
or QIODevice::ReadWrite. Other modes are unsupported. |
sa QIODevice::OpenMode, setPort() |
*/ |
boolQSerialPort::open(OpenMode mode) |
{ |
Q_D(QSerialPort); |
if (isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::OpenError)); |
returnfalse; |
} |
// Define while not supported modes. |
staticconst OpenMode unsupportedModes = Append Truncate Text Unbuffered; |
if ((mode & unsupportedModes) mode NotOpen) { |
d->setError(QSerialPortErrorInfo(QSerialPort::UnsupportedOperationError, tr('Unsupported open mode'))); |
returnfalse; |
} |
clearError(); |
if (!d->open(mode)) |
returnfalse; |
QIODevice::open(mode); |
returntrue; |
} |
/*! |
reimp |
note The serial port has to be open before trying to close it; otherwise |
sets the NotOpenError error code. |
sa QIODevice::close() |
*/ |
voidQSerialPort::close() |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
return; |
} |
d->close(); |
d->isBreakEnabled = false; |
QIODevice::close(); |
} |
QT_WARNING_PUSH |
QT_WARNING_DISABLE_DEPRECATED |
#if QT_DEPRECATED_SINCE(5, 3) |
/*! |
property QSerialPort::settingsRestoredOnClose |
brief the flag which specifies to restore the previous settings when closing |
the serial port. |
obsolete |
If this flag is c true, the settings will be restored; otherwise not. |
The default state of the QSerialPort class is to restore the |
settings. |
*/ |
voidQSerialPort::setSettingsRestoredOnClose(bool restore) |
{ |
Q_D(QSerialPort); |
if (d->settingsRestoredOnClose != restore) { |
d->settingsRestoredOnClose = restore; |
emit settingsRestoredOnCloseChanged(d->settingsRestoredOnClose); |
} |
} |
QT_WARNING_POP |
boolQSerialPort::settingsRestoredOnClose() const |
{ |
Q_D(const QSerialPort); |
return d->settingsRestoredOnClose; |
} |
#endif// QT_DEPRECATED_SINCE(5,3) |
#if QT_DEPRECATED_SINCE(5, 5) |
/*! |
fn void QSerialPort::settingsRestoredOnCloseChanged(bool restore) |
obsolete |
This signal is emitted after the flag which specifies to restore the |
previous settings while closing the serial port has been changed. The new |
flag which specifies to restore the previous settings while closing the serial |
port is passed as a restore. |
sa QSerialPort::settingsRestoredOnClose |
*/ |
#endif// QT_DEPRECATED_SINCE(5, 5) |
/*! |
property QSerialPort::baudRate |
brief the data baud rate for the desired direction |
If the setting is successful or set before opening the port, returns c true; |
otherwise returns c false and sets an error code which can be obtained by |
accessing the value of the QSerialPort::error property. To set the baud |
rate, use the enumeration QSerialPort::BaudRate or any positive qint32 |
value. |
note If the setting is set before opening the port, the actual serial port |
setting is done automatically in the l{QSerialPort::open()} method right |
after that the opening of the port succeeds. |
warning Setting the AllDirections flag is supported on all platforms. |
Windows supports only this mode. |
warning Returns equal baud rate in any direction on Windows. |
The default value is Baud9600, i.e. 9600 bits per second. |
*/ |
boolQSerialPort::setBaudRate(qint32 baudRate, Directions directions) |
{ |
Q_D(QSerialPort); |
if (!isOpen() d->setBaudRate(baudRate, directions)) { |
if (directions & QSerialPort::Input) { |
if (d->inputBaudRate != baudRate) |
d->inputBaudRate = baudRate; |
else |
directions &= ~QSerialPort::Input; |
} |
if (directions & QSerialPort::Output) { |
if (d->outputBaudRate != baudRate) |
d->outputBaudRate = baudRate; |
else |
directions &= ~QSerialPort::Output; |
} |
if (directions) |
emit baudRateChanged(baudRate, directions); |
returntrue; |
} |
returnfalse; |
} |
qint32 QSerialPort::baudRate(Directions directions) const |
{ |
Q_D(const QSerialPort); |
if (directions QSerialPort::AllDirections) |
return d->inputBaudRate d->outputBaudRate ? |
d->inputBaudRate : -1; |
return directions & QSerialPort::Input ? d->inputBaudRate : d->outputBaudRate; |
} |
/*! |
fn void QSerialPort::baudRateChanged(qint32 baudRate, Directions directions) |
This signal is emitted after the baud rate has been changed. The new baud |
rate is passed as a baudRate and directions as a directions. |
sa QSerialPort::baudRate |
*/ |
/*! |
property QSerialPort::dataBits |
brief the data bits in a frame |
If the setting is successful or set before opening the port, returns |
c true; otherwise returns c false and sets an error code which can be obtained |
by accessing the value of the QSerialPort::error property. |
note If the setting is set before opening the port, the actual serial port |
setting is done automatically in the l{QSerialPort::open()} method right |
after that the opening of the port succeeds. |
The default value is Data8, i.e. 8 data bits. |
*/ |
boolQSerialPort::setDataBits(DataBits dataBits) |
{ |
Q_D(QSerialPort); |
if (!isOpen() d->setDataBits(dataBits)) { |
if (d->dataBits != dataBits) { |
d->dataBits = dataBits; |
emit dataBitsChanged(d->dataBits); |
} |
returntrue; |
} |
returnfalse; |
} |
QSerialPort::DataBits QSerialPort::dataBits() const |
{ |
Q_D(const QSerialPort); |
return d->dataBits; |
} |
/*! |
fn void QSerialPort::dataBitsChanged(DataBits dataBits) |
This signal is emitted after the data bits in a frame has been changed. The |
new data bits in a frame is passed as a dataBits. |
sa QSerialPort::dataBits |
*/ |
/*! |
property QSerialPort::parity |
brief the parity checking mode |
If the setting is successful or set before opening the port, returns c true; |
otherwise returns c false and sets an error code which can be obtained by |
accessing the value of the QSerialPort::error property. |
note If the setting is set before opening the port, the actual serial port |
setting is done automatically in the l{QSerialPort::open()} method right |
after that the opening of the port succeeds. |
The default value is NoParity, i.e. no parity. |
*/ |
boolQSerialPort::setParity(Parity parity) |
{ |
Q_D(QSerialPort); |
if (!isOpen() d->setParity(parity)) { |
if (d->parity != parity) { |
d->parity = parity; |
emit parityChanged(d->parity); |
} |
returntrue; |
} |
returnfalse; |
} |
QSerialPort::Parity QSerialPort::parity() const |
{ |
Q_D(const QSerialPort); |
return d->parity; |
} |
/*! |
fn void QSerialPort::parityChanged(Parity parity) |
This signal is emitted after the parity checking mode has been changed. The |
new parity checking mode is passed as a parity. |
sa QSerialPort::parity |
*/ |
/*! |
property QSerialPort::stopBits |
brief the number of stop bits in a frame |
If the setting is successful or set before opening the port, returns c true; |
otherwise returns c false and sets an error code which can be obtained by |
accessing the value of the QSerialPort::error property. |
note If the setting is set before opening the port, the actual serial port |
setting is done automatically in the l{QSerialPort::open()} method right |
after that the opening of the port succeeds. |
The default value is OneStop, i.e. 1 stop bit. |
*/ |
boolQSerialPort::setStopBits(StopBits stopBits) |
{ |
Q_D(QSerialPort); |
if (!isOpen() d->setStopBits(stopBits)) { |
if (d->stopBits != stopBits) { |
d->stopBits = stopBits; |
emit stopBitsChanged(d->stopBits); |
} |
returntrue; |
} |
returnfalse; |
} |
QSerialPort::StopBits QSerialPort::stopBits() const |
{ |
Q_D(const QSerialPort); |
return d->stopBits; |
} |
/*! |
fn void QSerialPort::stopBitsChanged(StopBits stopBits) |
This signal is emitted after the number of stop bits in a frame has been |
changed. The new number of stop bits in a frame is passed as a stopBits. |
sa QSerialPort::stopBits |
*/ |
/*! |
property QSerialPort::flowControl |
brief the desired flow control mode |
If the setting is successful or set before opening the port, returns c true; |
otherwise returns c false and sets an error code which can be obtained by |
accessing the value of the QSerialPort::error property. |
note If the setting is set before opening the port, the actual serial port |
setting is done automatically in the l{QSerialPort::open()} method right |
after that the opening of the port succeeds. |
The default value is NoFlowControl, i.e. no flow control. |
*/ |
boolQSerialPort::setFlowControl(FlowControl flowControl) |
{ |
Q_D(QSerialPort); |
if (!isOpen() d->setFlowControl(flowControl)) { |
if (d->flowControl != flowControl) { |
d->flowControl = flowControl; |
emit flowControlChanged(d->flowControl); |
} |
returntrue; |
} |
returnfalse; |
} |
QSerialPort::FlowControl QSerialPort::flowControl() const |
{ |
Q_D(const QSerialPort); |
return d->flowControl; |
} |
/*! |
fn void QSerialPort::flowControlChanged(FlowControl flow) |
This signal is emitted after the flow control mode has been changed. The |
new flow control mode is passed as a flow. |
sa QSerialPort::flowControl |
*/ |
/*! |
property QSerialPort::dataTerminalReady |
brief the state (high or low) of the line signal DTR |
Returns c true on success, c false otherwise. |
If the flag is c true then the DTR signal is set to high; otherwise low. |
note The serial port has to be open before trying to set or get this |
property; otherwise c false is returned and the error code is set to |
NotOpenError. |
sa pinoutSignals() |
*/ |
boolQSerialPort::setDataTerminalReady(bool set) |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
returnfalse; |
} |
constbool dataTerminalReady = isDataTerminalReady(); |
constbool retval = d->setDataTerminalReady(set); |
if (retval && (dataTerminalReady != set)) |
emit dataTerminalReadyChanged(set); |
return retval; |
} |
boolQSerialPort::isDataTerminalReady() |
{ |
Q_D(QSerialPort); |
return d->pinoutSignals() & QSerialPort::DataTerminalReadySignal; |
} |
/*! |
fn void QSerialPort::dataTerminalReadyChanged(bool set) |
This signal is emitted after the state (high or low) of the line signal DTR |
has been changed. The new the state (high or low) of the line signal DTR is |
passed as a set. |
sa QSerialPort::dataTerminalReady |
*/ |
/*! |
property QSerialPort::requestToSend |
brief the state (high or low) of the line signal RTS |
Returns c true on success, c false otherwise. |
If the flag is c true then the RTS signal is set to high; otherwise low. |
note The serial port has to be open before trying to set or get this |
property; otherwise c false is returned and the error code is set to |
NotOpenError. |
note An attempt to control the RTS signal in the HardwareControl mode |
will fail with error code set to UnsupportedOperationError, because |
the signal is automatically controlled by the driver. |
sa pinoutSignals() |
*/ |
boolQSerialPort::setRequestToSend(bool set) |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
returnfalse; |
} |
if (d->flowControl QSerialPort::HardwareControl) { |
d->setError(QSerialPortErrorInfo(QSerialPort::UnsupportedOperationError)); |
returnfalse; |
} |
constbool requestToSend = isRequestToSend(); |
constbool retval = d->setRequestToSend(set); |
if (retval && (requestToSend != set)) |
emit requestToSendChanged(set); |
return retval; |
} |
boolQSerialPort::isRequestToSend() |
{ |
Q_D(QSerialPort); |
return d->pinoutSignals() & QSerialPort::RequestToSendSignal; |
} |
/*! |
fn void QSerialPort::requestToSendChanged(bool set) |
This signal is emitted after the state (high or low) of the line signal RTS |
has been changed. The new the state (high or low) of the line signal RTS is |
passed as a set. |
sa QSerialPort::requestToSend |
*/ |
/*! |
Returns the state of the line signals in a bitmap format. |
From this result, it is possible to allocate the state of the |
desired signal by applying a mask 'AND', where the mask is |
the desired enumeration value from QSerialPort::PinoutSignals. |
note This method performs a system call, thus ensuring that the line signal |
states are returned properly. This is necessary when the underlying |
operating systems cannot provide proper notifications about the changes. |
note The serial port has to be open before trying to get the pinout |
signals; otherwise returns NoSignal and sets the NotOpenError error code. |
sa QSerialPort::dataTerminalReady, QSerialPort::requestToSend |
*/ |
QSerialPort::PinoutSignals QSerialPort::pinoutSignals() |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
return QSerialPort::NoSignal; |
} |
return d->pinoutSignals(); |
} |
/*! |
This function writes as much as possible from the internal write |
buffer to the underlying serial port without blocking. If any data |
was written, this function returns c true; otherwise returns c false. |
Call this function for sending the buffered data immediately to the serial |
port. The number of bytes successfully written depends on the operating |
system. In most cases, this function does not need to be called, because the |
QSerialPort class will start sending data automatically once control is |
returned to the event loop. In the absence of an event loop, call |
waitForBytesWritten() instead. |
note The serial port has to be open before trying to flush any buffered |
data; otherwise returns c false and sets the NotOpenError error code. |
sa write(), waitForBytesWritten() |
*/ |
boolQSerialPort::flush() |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
returnfalse; |
} |
return d->flush(); |
} |
/*! |
Discards all characters from the output or input buffer, depending on |
given directions a directions. This includes clearing the internal class buffers and |
the UART (driver) buffers. Also terminate pending read or write operations. |
If successful, returns c true; otherwise returns c false. |
note The serial port has to be open before trying to clear any buffered |
data; otherwise returns c false and sets the NotOpenError error code. |
*/ |
boolQSerialPort::clear(Directions directions) |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
returnfalse; |
} |
if (directions & Input) |
d->buffer.clear(); |
if (directions & Output) |
d->writeBuffer.clear(); |
return d->clear(directions); |
} |
/*! |
reimp |
Returns c true if no more data is currently available for reading; otherwise |
returns c false. |
This function is most commonly used when reading data from the |
serial port in a loop. For example: |
code |
// This slot is connected to QSerialPort::readyRead() |
void QSerialPortClass::readyReadSlot() |
{ |
while (!port.atEnd()) { |
QByteArray data = port.read(100); |
.... |
} |
} |
endcode |
sa bytesAvailable(), readyRead() |
*/ |
boolQSerialPort::atEnd() const |
{ |
returnQIODevice::atEnd(); |
} |
#if QT_DEPRECATED_SINCE(5, 2) |
/*! |
property QSerialPort::dataErrorPolicy |
brief the error policy for how the process receives characters in the case where |
a parity error is detected. |
obsolete |
If the setting is successful, returns c true; otherwise returns c false. The |
default policy set is IgnorePolicy. |
note The serial port has to be open before trying to set this property; |
otherwise returns c false and sets the NotOpenError error code. This is a bit |
unusual as opposed to the regular Qt property settings of a class. However, |
this is a special use case since the property is set through the interaction |
with the kernel and hardware. Hence, the two scenarios cannot be completely |
compared to each other. |
*/ |
boolQSerialPort::setDataErrorPolicy(DataErrorPolicy policy) |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
returnfalse; |
} |
if (policy != QSerialPort::IgnorePolicy) { |
d->setError(QSerialPortErrorInfo(QSerialPort::UnsupportedOperationError, |
tr('The device supports only the ignoring policy'))); |
returnfalse; |
} |
returntrue; |
} |
QSerialPort::DataErrorPolicy QSerialPort::dataErrorPolicy() const |
{ |
return QSerialPort::IgnorePolicy; |
} |
#endif// QT_DEPRECATED_SINCE(5, 2) |
#if QT_DEPRECATED_SINCE(5, 5) |
/*! |
fn void QSerialPort::dataErrorPolicyChanged(DataErrorPolicy policy) |
obsolete |
This signal is emitted after the error policy for how the process receives |
characters in case of parity error detection has been changed. The new error |
policy for how the process receives the character in case of parity error |
detection is passed as a policy. |
sa QSerialPort::dataErrorPolicy |
*/ |
#endif// QT_DEPRECATED_SINCE(5, 5) |
/*! |
property QSerialPort::error |
brief the error status of the serial port |
The I/O device status returns an error code. For example, if open() |
returns c false, or a read/write operation returns c -1, this property can |
be used to figure out the reason why the operation failed. |
The error code is set to the default QSerialPort::NoError after a call to |
clearError() |
*/ |
QSerialPort::SerialPortError QSerialPort::error() const |
{ |
Q_D(const QSerialPort); |
return d->error; |
} |
voidQSerialPort::clearError() |
{ |
Q_D(QSerialPort); |
d->setError(QSerialPortErrorInfo(QSerialPort::NoError)); |
} |
/*! |
fn void QSerialPort::error(SerialPortError error) |
obsolete |
Use errorOccurred() instead. |
*/ |
/*! |
fn void QSerialPort::errorOccurred(SerialPortError error) |
since 5.8 |
This signal is emitted when an error occurs in the serial port. |
The specified a error describes the type of error that occurred. |
sa QSerialPort::error |
*/ |
/*! |
Returns the size of the internal read buffer. This limits the |
amount of data that the client can receive before calling the read() |
or readAll() methods. |
A read buffer size of c 0 (the default) means that the buffer has |
no size limit, ensuring that no data is lost. |
sa setReadBufferSize(), read() |
*/ |
qint64 QSerialPort::readBufferSize() const |
{ |
Q_D(const QSerialPort); |
return d->readBufferMaxSize; |
} |
/*! |
Sets the size of QSerialPort's internal read buffer to be a |
size bytes. |
If the buffer size is limited to a certain size, QSerialPort |
will not buffer more than this size of data. The special case of a buffer |
size of c 0 means that the read buffer is unlimited and all |
incoming data is buffered. This is the default. |
This option is useful if the data is only read at certain points |
in time (for instance in a real-time streaming application) or if the serial |
port should be protected against receiving too much data, which may |
eventually cause the application to run out of memory. |
sa readBufferSize(), read() |
*/ |
voidQSerialPort::setReadBufferSize(qint64 size) |
{ |
Q_D(QSerialPort); |
d->readBufferMaxSize = size; |
if (isReadable()) |
d->startAsyncRead(); |
} |
/*! |
reimp |
Always returns c true. The serial port is a sequential device. |
*/ |
boolQSerialPort::isSequential() const |
{ |
returntrue; |
} |
/*! |
reimp |
Returns the number of incoming bytes that are waiting to be read. |
sa bytesToWrite(), read() |
*/ |
qint64 QSerialPort::bytesAvailable() const |
{ |
returnQIODevice::bytesAvailable(); |
} |
/*! |
reimp |
Returns the number of bytes that are waiting to be written. The |
bytes are written when control goes back to the event loop or |
when flush() is called. |
sa bytesAvailable(), flush() |
*/ |
qint64 QSerialPort::bytesToWrite() const |
{ |
qint64 pendingBytes = QIODevice::bytesToWrite(); |
#if defined(Q_OS_WIN32) |
pendingBytes += d_func()->writeChunkBuffer.size(); |
#endif |
return pendingBytes; |
} |
/*! |
reimp |
Returns c true if a line of data can be read from the serial port; |
otherwise returns c false. |
sa readLine() |
*/ |
boolQSerialPort::canReadLine() const |
{ |
returnQIODevice::canReadLine(); |
} |
/*! |
reimp |
This function blocks until new data is available for reading and the |
l{QIODevice::}{readyRead()} signal has been emitted. The function |
will timeout after a msecs milliseconds; the default timeout is |
30000 milliseconds. If a msecs is -1, this function will not time out. |
The function returns c true if the readyRead() signal is emitted and |
there is new data available for reading; otherwise it returns c false |
(if an error occurred or the operation timed out). |
sa waitForBytesWritten() |
*/ |
boolQSerialPort::waitForReadyRead(int msecs) |
{ |
Q_D(QSerialPort); |
return d->waitForReadyRead(msecs); |
} |
/*! |
fn Handle QSerialPort::handle() const |
since 5.2 |
If the platform is supported and the serial port is open, returns the native |
serial port handle; otherwise returns c -1. |
warning This function is for expert use only; use it at your own risk. |
Furthermore, this function carries no compatibility promise between minor |
Qt releases. |
*/ |
/*! |
reimp |
This function blocks until at least one byte has been written to the serial |
port and the l{QIODevice::}{bytesWritten()} signal has been emitted. The |
function will timeout after a msecs milliseconds; the default timeout is |
30000 milliseconds. If a msecs is -1, this function will not time out. |
The function returns c true if the bytesWritten() signal is emitted; otherwise |
it returns c false (if an error occurred or the operation timed out). |
*/ |
boolQSerialPort::waitForBytesWritten(int msecs) |
{ |
Q_D(QSerialPort); |
return d->waitForBytesWritten(msecs); |
} |
#if QT_DEPRECATED_SINCE(5, 5) |
/*! |
Sends a continuous stream of zero bits during a specified period |
of time a duration in msec if the terminal is using asynchronous |
serial data. If successful, returns c true; otherwise returns c false. |
If the duration is zero then zero bits are transmitted by at least |
c 0.25 seconds, but no more than c 0.5 seconds. |
If the duration is non zero then zero bits are transmitted within a certain |
period of time depending on the implementation. |
note The serial port has to be open before trying to send a break |
duration; otherwise returns c false and sets the NotOpenError error code. |
sa setBreakEnabled() |
*/ |
boolQSerialPort::sendBreak(int duration) |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
returnfalse; |
} |
return d->sendBreak(duration); |
} |
#endif// QT_DEPRECATED_SINCE(5, 5) |
/*! |
property QSerialPort::breakEnabled |
since 5.5 |
brief the state of the transmission line in break |
Returns c true on success, c false otherwise. |
If the flag is c true then the transmission line is in break state; |
otherwise is in non-break state. |
note The serial port has to be open before trying to set or get this |
property; otherwise returns c false and sets the NotOpenError error code. |
This is a bit unusual as opposed to the regular Qt property settings of |
a class. However, this is a special use case since the property is set |
through the interaction with the kernel and hardware. Hence, the two |
scenarios cannot be completely compared to each other. |
*/ |
boolQSerialPort::setBreakEnabled(bool set) |
{ |
Q_D(QSerialPort); |
if (!isOpen()) { |
d->setError(QSerialPortErrorInfo(QSerialPort::NotOpenError)); |
qWarning('%s: device not open', Q_FUNC_INFO); |
returnfalse; |
} |
if (d->setBreakEnabled(set)) { |
if (d->isBreakEnabled != set) { |
d->isBreakEnabled = set; |
emit breakEnabledChanged(d->isBreakEnabled); |
} |
returntrue; |
} |
returnfalse; |
} |
boolQSerialPort::isBreakEnabled() const |
{ |
Q_D(const QSerialPort); |
return d->isBreakEnabled; |
} |
/*! |
reimp |
*/ |
// This function does not really read anything, as we use QIODevicePrivate's |
// buffer. The buffer will be read inside of QIODevice before this |
// method will be called. |
qint64 QSerialPort::readData(char *data, qint64 maxSize) |
{ |
Q_UNUSED(data); |
Q_UNUSED(maxSize); |
// In any case we need to start the notifications if they were |
// disabled by the read handler. If enabled, next call does nothing. |
d_func()->startAsyncRead(); |
// return 0 indicating there may be more data in the future |
returnqint64(0); |
} |
/*! |
reimp |
*/ |
qint64 QSerialPort::readLineData(char *data, qint64 maxSize) |
{ |
returnQIODevice::readLineData(data, maxSize); |
} |
/*! |
reimp |
*/ |
qint64 QSerialPort::writeData(constchar *data, qint64 maxSize) |
{ |
Q_D(QSerialPort); |
return d->writeData(data, maxSize); |
} |
#include'moc_qserialport.cpp' |
QT_END_NAMESPACE |
Common Serial Baud Rates
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