Qextserual can't detect virtual com-port

Hey everybody,

just got a question if anyone noticed similar problem to mine..

im using qt 4.5 with qexserialport 1.2 alpha

got a device connected to USB Serial Port (FTDI)

I noticed that it actually cant detect it...

Code:

---

QextSerialEnumerator enumer;
QList<QextPortInfo>ports = enumer.getPorts();
QStringList strlist;
strlist.clear();
for( int i = 0; i < ports.count(); ++i) strlist << ports.at(i).portName;
ui.comboBox_Comm->addItems(strlist);

---

In fact i have got the info from real comm-port, but can't get the info from virtual comm-port:confused:

thanks!
Jim

I don't use this alpha version of Qextserialport.

You can scan a list of QString("COM%1").arg(i) and try to open the port: if you can open it, there is an available port. On Linux you can query the list of /dev/ttyS* and /dev/ttyUSB*.

Quote:

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Originally Posted by PaceyIV

I don't use this alpha version of Qextserialport.

You can scan a list of QString("COM%1").arg(i) and try to open the port: if you can open it, there is an available port. On Linux you can query the list of /dev/ttyS* and /dev/ttyUSB*.

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thanks, but i have got the list of com port information, but except for the vitual com port..

I don't understand. What's the difference between a virtual-com and a real-com port?
If I connect my Arduino with the USB cable on my PC (a microcontroller with the FTDI chip), Windows, same as Linux, shows me a COM3 or a /dev/ttyUSB0. This is a virtual com port, but the system operator is the only subject that knows this. Any programs see that port as a real serial port.

indeed, i can see the virtual-com port under device management (windows), und i can use other software to open the port, but, only my Qt code, as i described, can't detect die virtual-com port.
so i don't understand, if the QextSerialEnumerator support the virtual-device or not..

Quote:

---

Originally Posted by PaceyIV

I don't use this alpha version of Qextserialport.

You can scan a list of QString("COM%1").arg(i) and try to open the port: if you can open it, there is an available port. On Linux you can query the list of /dev/ttyS* and /dev/ttyUSB*.

---

however, i notice that you can scan the port with a normal version of Qextserialport?
I used the alpha version of Qextserialport because it can easy detect the port information.

Here my code.

Code:

---

// Query available SerialPort name
 
QStringList MySerialPort::availablePortsName()
 
{
 
    QextSerialPort testPort;
    testPort.setBaudRate(BAUD115200);
    testPort.setFlowControl(FLOW_OFF);
    testPort.setParity(PAR_NONE);
    testPort.setDataBits(DATA_8);
    testPort.setStopBits(STOP_1);
 
    QStringList portsName;
    QString testPortName;
 
#ifdef _WIN
    for (int i=1; i<MAX_COM_PORT; i++)
    {
        testPortName = QString("COM%1").arg(i);
        testPort.setPortName(testPortName);
        if (testPort.open(QIODevice::ReadWrite))
        {
            portsName.append(testPortName);
            testPort.close();
        }
    }
 
#else // _UNIX
    QDir dir("/dev");
    QStringList filters;
 
    filters << "ttyS*" << "ttyUSB*";
    dir.setNameFilters(filters);
    dir.setFilter(QDir::Files | QDir::System);
    QFileInfoList list = dir.entryInfoList();
 
    for (int i=0; i< list.size(); i++)
    {
        portsName.append(list.at(i).canonicalFilePath ());
    }
#endif
 
    return portsName;
}

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thanks a lot, i will try it later!

Hi,

I use code very similiar to the one PaceyIV posted.
The problem is that my system gets blocked whenever a COM Port is not existing but Qt tries to open it anyways. My whole application freezes for about 5 seconds
I have two ideas for a solution.
Let the open methods run in the background. How? I dont know.
Set a timeout for the open method. How? I dont know.

Another option would be a different code that avoids opening ports that dont exist, is there a solution for that?

Any help is highly appreciated.

hi i want to get the corresponding port name when we choose a printer name in a combobox.....i stuck with it for few days,,,kindly help me'