Detect if the Fn key has been pressed

[PascalDragon]

According to stack overflow (and other) answers, the Fn key does not generate a scan code. It is handled by the low-level keyboard drivers on platforms where it is implemented. Windows uses the Registry (of course it does).

It's more likely the Fn key is handled inside the hardware itself instead of the driver, because that is usually simply a generic HID driver. In that case there won't be any notification to the OS about the key.