Post

Note for Windows PC users - apologies for the shift keys not working properly. I've mapped left shift to CAPS SHIFT and right shift to SYMBOL SHIFT. For some reason a KEYUP event consistently goes missing when you hold both shift keys then release one or both. Works fine on Linux and Mac.

2/9/26, 12:53 pm0 reposts5 likes

Word on the street is that this is some weird legacy Microsoft Windows thing, which I've confirmed with a test Windows app I wrote. I can't find any official documentation on this though other than a mention in this thread. github.com/libsdl-org/S...

I'll be updating the emulator shortly so that it uses another key sequence for Windows users.

It's probably telling that the other online emulators I've tried (jsspeccy, qaop) use left shift for CAPS SHIFT and alt-gr for SYMBOL SHIFT. Might as well fall in line with them.

zx.researcher.suZX Spectrum emulator onlineLow-level emulation of devices. Wide image and snapshot formats support.

Ah, just found one that uses both shift keys and it suffers the same problem as mine. This one appears to be written in JavaScript.

Gaz

@gazchap.com

Something to do with StickyKeys?

Dunno what the reason is.

Tom Keresztes

@tkeresztes.bsky.social

Are you using VK_SHIFT ?

No, In my distilled Windows test example I'm using VK_LSHIFT and VK_RSHIFT in the messages WM_KEYUP/DOWN. In the emulator I'm using SDLK_LSHIFT/RSHIFT.

Tom Keresztes

@tkeresztes.bsky.social

windows treats modifier state as unified , e.g. here both shift keys, but will only send one keyup when the last is released. you can call getkeystate for vk_lshit and rshift on every shift event (keyup, down, syskeyup, etc) like bool ls = GetKeyState(VK_LSHIFT) & 0x8000) != 0 . or raw input.

Indeed, that's pretty much what I'm seeing, and I can also confirm that the shift keys can be read correctly using GetKeyState. The key up/down events are all I've got to work with at the moment as it needs to be cross-platform. I'll come back to it when I've got more time on my hands.

Tom Keresztes

@tkeresztes.bsky.social