I want to be able to intercept (and do arbitrary processing on) auto-repeating key presses on Windows. I'd like to know how keyboard auto-repeat is implemented so that I know what options I have. i.e. can I intercept at the:
?
Update: It looks like auto-repeat is (poorly?) generated at the hardware level and then overridden by device drivers (see here).
To modify or filter behavior, you can intercept keys using a hook:
SetWindowsHookEx
using WH_KEYBOARD
The hook procedure receives, among others, the repeat count (due to holding down the key)
Note that the low level keyboard hook (WH_KEYBOARD_LL
) does not receive the repeat count.
If all your windows are created in the same trhead, you can use a thread-specific hook, and avoid moving the hook procedure to a DLL.
I dimly remember that repeat counts are generated by the keyboard itself and the LL hook sends repeated keydown events - I may be mistaken, though. Under DOS, the key repeat rate and time that was set in BIOS or through a BIOS call did return to default values when a DIN or PS/2 keyboard was unplugged and replugged. I am not sure WHY you need to know exactly.