Controlling keyboard LED lights using c

Question

I want to create a program to represent binary numbers using keyboards LED flash. I don't know how to begin with controlling those LED lights using C language?

Answer 1

For Linux, this would be helpful

setleds

A more comprehensive internals and several command line utilities description

Keyboard and console - HowTo.pdf

Answer 2

For windows:

Because the SetKeyboardState function alters the input state of the calling thread and not the global input state of the system, an application cannot use SetKeyboardState to set the NUM LOCK, CAPS LOCK, or SCROLL LOCK (or the Japanese KANA) indicator lights on the keyboard. These can be set or cleared using SendInput to simulate keystrokes.

See Windows API ref