SDL2 Alt key not propogated

[bjadamson]

SDL2 Alt key not propogated

[Bill-Gray]

Thanks for the report and fix. I'd heard about this problem a couple of weeks ago, determined it had been broken since at least 2020, and hadn't figured out a fix.

Part of what threw me is that the error only affects Microsoft Windows. Applying your fix to Linux and building testcurs and running the input test, hitting Alt-keys gets you duplicate key presses. On Linux, _handle_alt_keys() is called earlier in the function, and you don't want to call it twice.

I think the fix will involve setting a we_already_called_handle_alt_keys Boolean to TRUE, and then (at lines 299-300) only calling _handle_alt_keys() if that Boolean is still FALSE.

That fix would work, but we'd still have the question of why it works one way on Linux and a different way in Microsoft Windows. SDLn is supposed to (and for the most part does) get you around these platform-specific details. So there may be some "gotchas" not yet figured out... but I think you've at least got us on the right track.

[bjadamson]

Thanks -- it took me a minute to get back to you but looks good to me. I agree that it behaving on linux like that is weird.