Create virtual serial port in Qt/C++

Question

I would like to create a linux app which appears as a serial port (eg /dev/ttyTEST). This app will listen for commands sent to the port, and respond back.

Is this possible using Qt/C++ ? I haven't done kernel programming so I'm hoping this is possible in user space.

Answer 1

Everything depends on what the application using such device expects.

If /dev/ttyTEST is to behave like a real serial device and respond properly to all ioctl's that set its speed etc., then this can't be done from userspace. It wouldn't be too hard to implement in the kernel space, though.

If /dev/ttyTEST only needs to be a tty, then provide a pseudo tty.

If /dev/ttyTEST is merely to be something another application can write to and read from then socketpair() does it.

If you have control over the application's code, then you can have it check whether the device is a socket pair or a real character device, and ignore the failures of the serial-port-specific APIs on a socket.