Use pseudo terminals with qt-serial on OSX

AlexanderB · 8 Jan 2019, 06:18

Hi all!

I'm trying to use pseudo terminals in a QT application on OSX, but run into an exception when starting the program.

I am using eg /dev/ptyp0 and /dev/ttyp0. When using those with screen I can open both and see the input of the one echoed in the other.

I am using the QT async serial port example to connect to /dev/ttyp0, but always get the following error:

QSocketNotifier: Invalid socket 7 with type Read, disabling...

What am I doing wrong, and does someone have a working example?

Thanks in advance!

SGaist · wrote on 7 Jan 2019, 22:30

Hi and welcome to devnet,

What are these two devices ?

aha_1980 · wrote on 8 Jan 2019, 06:18

@kuzulis Any idea?

kuzulis · 1 Aug 2019, 10:09

I have not ideas. I just can say that:

Pseudo terminals are not a serial ports.
Try to use socat.
Any errors related to QSocketNotifier - is not a QSerialPort issues (you can address it to QtCore team). :)

AlexanderB · wrote on 8 Jan 2019, 14:29

@kuzulis said in Use pseudo terminals with qt-serial on OSX:

I have not ideas. I just can say that:

Pseudo terminals are not a serial ports.

I know, but they do behave as serial ports. From the first link: "Thus two programs talk to each other via this method and one program on ttyp3 thinks it's talking to a serial port.".

Try to use socat.

Can I use socat to mock a serial device? What I want to do is to mock a serial device, so that it responds to requests from my actual program as if it was an actual device (with a somewhat limited/fixed response).

As long as my actual program connects to a serial port, I am fine with any other solution!

Any errors related to QSocketNotifier - is not a QSerialPort issues (you can address it to QtCore team). :)

Is this the right sub-forum for it, or should I post my question in another one as well?

Thanks in advance!

AlexanderB · wrote on 8 Jan 2019, 14:59

@kuzulis I've had a look at socat, and that looks to work! I now have a small example where I can write/read from a serial port. On the other end I am using screen, and my program picks up data as expected!

Thanks for the pointer to socat! Didn't know about it..