GUI Ctrl's and Func's

[Aces]

#include <GUIConstants.au3>

GUICreate("CPU-Mach V0.1 - Made by Aces", 300,400)

$shutdown = GUICtrlCreateButton("Power Off", 10, 10, 100, 50)

GUISetState()

While 1

$msg = GuiGetMsg()

If $msg = $GUI_EVENT_CLOSE Then ExitLoop

WEnd

Func poweroff()

MsgBox(0, "Shutdown", "Your CPU will power off when you press OK.")

Shutdown(9)

EndFunc

Func reboot()

Shutdown(3)

EndFunc

Func logoff()

Shutdown(0)

EndFunc

How do I add one of my functions [let's say poweroff()], to the button I added?

[poisonkiller]

Add "If $msg = $shutdown Then poweroff()" after $GUI_EVENT_CLOSE line.