From: Norman Makoto Su <makoto@...4.berkeley.edu>
Date: 2001-05-31T11:24:39+09:00
Subject: [ruby-talk:16069] KeyboardState w/ Win32Api

Hello,

I'm trying to use the Win32API library in ruby to force num-lock.  I found
the following perl snippet (which should work with perl, I think) on the net
and I converted it to ruby:

use Win32::API;
  $GetKeyboardState = new Win32::API('user32', 'GetKeyboardState',
    ['P'], 'N');
  $SetKeyboardState = new Win32::API('user32', 'SetKeyboardState',
    ['P'], 'V');
  my $keyboardstate = "\0" x 256;
  $GetKeyboardState->Call($keyboardstate);
  substr($keyboardstate, 0x90, 1) = chr(1);  # VK_NUMLOCK = 0x90
  $SetKeyboardState->Call($keyboardstate);

-------ruby below----------

VK_NUMLOCK = 0x90

getKeyboardState = Win32API.new('user32', 'GetKeyboardState', ['P'], 'N')
setKeyboardState = Win32API.new('user32', 'SetKeyboardState', ['P'], 'V')

state = 0.chr * 256
getKeyboardState.call(state)
state[VK_NUMLOCK] = 1.chr
setKeyboardState.call(state)

However, this does not change the num-lock; in fact, nothing at all happens
(no errors either).  I've tried making a keyboard state byte array when I
set caps lock, num lock, or press shift down.  Then, I compared that to a
keyboard state where I press nothing on the keyboard but it seems that there
is no difference; for some reason, the keyboard state is not recording
correctly?  BTW, GetKeyboardState takes in a byte array and writes to it.
Do I need to unpack it somehow?  Since there is no byte type in ruby-- I'm
guessing character should work too...

I'm using cygwin version 1.3.2 on Windows 98 (Japanese edition) and ruby
version 1.6.3 [i386-cygwin].  Any help would be greatly appreciated.

Thank you,

Norman Su