Feature request: Support exiting event loop without quitting program

[surban]

I am using winit via eframe for a command line application. The app displays a window for the user to provide some input. After the window is closed I would like winit to exit the event loop and return from EventLoop::run, so that the app can continue running.

However this is currently impossible because the return type is ! and std::process::exit is called when the event loop is exited.

See also emilk/egui#1223

[maroider]

See EventLoopExtRunReturn::run_return

[surban]

Unfortunately, according to the egui developers this is not working properly, see emilk/egui#1223 (comment).

[maroider]

My intuition is that even if run_return leads to "very jittery resizing of windows", such behaviour should only manifest if one repeatedly returns and re-enters the event loop. For your use-case, which seems to call for exiting the event loop a single time once you've shown your prompt, seems like it might work without much of an issue. run uses run_return under the hood, so I don't think there's much room for additional bugs to sneak in (ignoring the previously mentioned "return + re-enter" case).

[kchibisov]

I'm not sure what the issue to solve here, run just calls run_return on desktop platforms iirc. run_return isn't possible on mobile iirc, but that's about it.

[lucafulgenzi]

@surban I am in the same situation as you, have you found an alternative method? Or have you changed libraries, if so could you tell me which one you used?

[rib]

I'm not sure what the issue to solve here, run just calls run_return on desktop platforms iirc. run_return isn't possible on mobile iirc, but that's about it.

run_return should be ok on Android I think (at least I can't think of a reason off the top of my head why it wouldn't work)

[lucafulgenzi]

It is not for android

[rib]

It is not for android

yeah, I was just thinking about the comment about run_return potentially not being supported on mobile. I've added a quote to clarify what I was commenting on.

[surban]

@surban I am in the same situation as you, have you found an alternative method? Or have you changed libraries, if so could you tell me which one you used?

I haven't tried myself, but wasn't this fixed in egui in emilk/egui#1889 ?