RubyでWin32 API を使ってPostMessageAしたい。

require 'Win32API'
class Win32AqiCall
WM_COMMAND = 0x0111
CHART_CMD_UPDATE_DATA = 33324
MB_OK = 0
def initialize
@message_box             = Win32API.new('user32', 'MessageBoxA', %w(p p p i), 'i')
@register_window_message = Win32API.new('user32', 'RegisterWindowMessageA', %w(p), 'i')
@find_window             = Win32API.new('user32', 'FindWindowA', %w(p p), 'l')
@find_window_ex          = Win32API.new('user32', 'FindWindowExA', %w(i i p p), 'l')
@post_message            = Win32API.new('user32', 'PostMessageA', %w(l l l l), 'l')
end
def MessageBox(wnd, text, caption, type = MB_OK)
@message_box.call(wnd, text, caption, type)
end
def RegisterWindowMessage(txt)
@register_window_message.call(txt)
end
def FindWindow(class_name, window_name)
@find_window.call(class_name, window_name)
end
def FindWindowEx(parent, child, class_name, window_name)
@find_window_ex.call(parent, child, class_name, window_name)
end
def PostMessage(hwnd, msg, wparam, lparam)
@post_message.call(hwnd, msg, wparam, lparam)
end
end