what is the USB HID code for the Compose key?

Question

I have a programmable USB keyboard for which I want to have a Compose key, like some keyboards from the Digital Equipment Corporation had. I need to know the USB HID code for this key.

I also have this list of USB HID codes. The only occurrence of the word Compose is below section LEDs which i suppose can’t be assigned to a key – or at least won’t be recognized as a Compose key by any operating system.

I know that in X11 the key is called Multi_key. But there is no multi key in this USB HID codes list.

Any ideas? Which one could it be?

Answer 1

In the X.org X11 server, K_COMPOSE is translated to XK_Multi_key in hw/dmx/input/lnx-keyboard.c:986. However, in Linux drivers/hid/hid-input.c, there is no code that gets mapped to KEY_COMPOSE.

(From your table, I'd choose one of the "Keyboard International" codes if I had to pick an existing one.)