Intercepting input from a barcode scanner (in keyboard emulation mode) or how to take input from a specific device?

Question

Keyboard

In general, there is a barcode scanner - mercury 1000 and the like.
They work in keyboard emulation mode.
I am writing a program, it is necessary to receive the value of the barcode in it, but in order to receive them, the form of the program must be constantly active, otherwise another application receives the input.
Option: activating the form before scanning is not suitable, because takes time and inconvenience of use.
Option: install special. the driver is not suitable, because it is not available for Linux (the rs232 emulator would be simple, but...).
The option with a separate computer is also not possible.
I know the device ID (according to the output of lsusb), I want to hang the program in the background and somehow determine what exactly the input is coming from this device.
Tell me, please, in c ++ where to look at least, what to take only from this particular device?

Answer 1

/dev/input/eventX
With RS232 emulation it is not clear, there are usually CP2103 or FT232, in a word - a classic for which there are drivers.