QApplication::keyboardModifiers() already reports the state of the shift/alt/control keys. The enum should be extended to report the state of Caps/Num/Scroll-Lock.

Update : unfortunately we simply do not have enough bits in our key codes left for these modifiers, so the enum cannot be extended further. What could be done is to add a separate function such as QApplication::keyboardLockModifiers() to query the state of these keys. This will be investigated for a future release.

On Windows, this could use GetAsyncKeyState with VK_CAPITAL, VK_NUMLOCK and VK_SCROLL.