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
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