Maybe you don't need another thread, just maybe an event loop (QEventLoop)?
> Sent: Thursday, April 04, 2019 at 10:43 AM
> From: "Jérôme Godbout" <godbo...@amotus.ca>
> To: "Paolo Angelelli" <paolo.angele...@qt.io>, "interest@qt-project.org"
> <interest@qt-project.org>
> Subject: Re: [Interest] Parsing data from serialport
>
> It relief the main thread from read data all the time and keep a good
> reactivity. The dedicated thread try to read and can wait until something
> come along and once it found something that can be parsed, it emit his own
> signal that the main thread only have to handle into normal slot (will be
> queued, since it's not the same thread).
>
> But yeah, you can have the main thread do it and process the readyRead(), you
> main thread will perform the read and parsing. if you have any CRC and other
> things, this might be bad for application reactivity, depending on the amount
> of data flowing.
>
> -----Original Message-----
> From: Interest <interest-boun...@qt-project.org> On Behalf Of Paolo Angelelli
> Sent: April 4, 2019 10:19 AM
> To: interest@qt-project.org
> Subject: Re: [Interest] Parsing data from serialport
>
> What is the advantage of having such a continuous reading loop in a separate
> thread?
>
> I mean it as opposed to reacting to the readyRead() signal, and having a
> while(canReadLine()) { ... } in the reacting slot.
>
>
> On Tue, 2 Apr 2019 22:01:49 +0000
> Jérôme Godbout <godbo...@amotus.ca> wrote:
>
> > Make sure your reading loop and processing data are separated. Call you
> > read device when needed or into a loop that can take some pause to avoid
> > 100% CPU usage for nothing.
> >
> > QByteArray buffer;
> >
> > void ReadDeviceHaveData()
> > {
> >
> > while(serial_port->bytesAvailable()) // This can be dangerous is
> > data keep coming and might be removed {
> > // You can read bytes per bytes or smaller chunk over here for
> > better reactivity and less memory consumption
> > buffer.append(serial_port->readAll());
> > processData();
> > serial_port->waitForReadyRead(5);
> > }
> > }
> >
> > void ProcessData()
> > {
> > int pos = buffer.indexOf(‘\n’);
> >
> > while(pos >= 0)
> > {
> > QByteArray line = buffer.left(pos);
> > // Strip trailing \r for windows here
> > // Do whatever you need with your line, check data integrity
> >
> > // Remove the processed data but leave the unprocessed data alone
> > buffer.remove(0, pos + 1); // Remove \n too
> > pos = buffer.indexOf(‘\n’);
> > }
> > }
> >
> > From: Interest <interest-boun...@qt-project.org> On Behalf Of Martin
> > Marmsoler
> > Sent: April 2, 2019 3:58 PM
> > To: Thiago Macieira <thiago.macie...@intel.com>
> > Cc: interest@qt-project.org
> > Subject: Re: [Interest] Parsing data from serialport
> >
> > > To be able to roll back, in case your reading from the device
> > didn't result in what you wanted or you got an error. See QDataStream.
> > Ah ok I understand.
> >
> > So this minimal example
> > QSerialPort sPort;
> > sPort.open(QIODevice::ReadOnly);
> >
> > if(sPort.waitForReadyRead(2000)){
> >
> > while (!device.atEnd()) {
> >
> > if (device.canReadLine()) {
> >
> > newData.push_back(device.readLine());
> >
> > linesToRead++;
> >
> > } else {
> >
> > return;
> >
> > }
> >
> > }
> >
> > ...
> >
> > }
> >
> > works fine, if I go trough it step by step (maybe, because enouth data come
> > in). But if I'm to fast it does not work.
> >
> > If I'm using the signal readyRead I will have the same problem,
> > because new data come everytime. So I check that in the
> >
> > readyRead function if a complete line come in, and if no complete line
> > I return without doing something otherwise I do
> >
> > something with the data? Is this the right way?
> >
> >
> >
> > Martin
> >
> >
> >
> >
> > Thiago Macieira
> > <thiago.macie...@intel.com<mailto:thiago.macie...@intel.com>> schrieb am
> > Di., 2. Apr. 2019, 18:02:
> > On Tuesday, 2 April 2019 07:04:03 PDT Martin Marmsoler wrote:
> > > Thank you Thiago for your response. But what is transactionstart for?
> >
> > To be able to roll back, in case your reading from the device didn't
> > result in what you wanted or you got an error. See QDataStream.
> >
> > --
> > Thiago Macieira - thiago.macieira (AT) intel.com<http://intel.com>
> > Software Architect - Intel System Software Products
> >
> >
> >
> > _______________________________________________
> > Interest mailing list
> > Interest@qt-project.org<mailto:Interest@qt-project.org>
> > https://lists.qt-project.org/listinfo/interest
>
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