The pollEvents function doesn't seem to work anymore!

[sdzx-1]

{-# LANGUAGE OverloadedStrings #-}
module Main where

import SDL
import Linear (V4(..))
import Control.Monad (unless)

main :: IO ()
main = do
  initializeAll
  window <- createWindow "My SDL Application" defaultWindow
  renderer <- createRenderer window (-1) defaultRenderer
  appLoop renderer
  destroyWindow window

appLoop :: Renderer -> IO ()
appLoop renderer = do
  events <- pollEvents
  print events  -- Here it keeps outputting [] even if I press the keyboard
  let eventIsQPress event =
        case eventPayload event of
          KeyboardEvent keyboardEvent ->
            keyboardEventKeyMotion keyboardEvent == Pressed &&
            keysymKeycode (keyboardEventKeysym keyboardEvent) == KeycodeQ
          _ -> False
      qPressed = any eventIsQPress events
  rendererDrawColor renderer $= V4 0 0 255 255
  clear renderer
  present renderer
  unless qPressed (appLoop renderer)

sdl2 version

➜  Yampa-Front git:(master) ✗ cabal build -v3 | grep sdl2
  sdl2-2.5.3.2-9b099619e5c5c8370254862105ad69cf154d7cf6e4baeb0b9983c7c55ab3c623
  sdl2-gfx-0.3.0.0-11abeb949b1f11da668c5899e3366da31ba7ecdd0844cc1f9ea315feb160c91a
Installed sdl2-2.5.3.2 (sdl2-2.5.3.2-9b099619e5c5c8370254862105ad69cf154d7cf6e4baeb0b9983c7c55ab3c623)
Installed sdl2-gfx-0.3.0.0 (sdl2-gfx-0.3.0.0-11abeb949b1f11da668c5899e3366da31ba7ecdd0844cc1f9ea315feb160c91a)
  sdl2-2.5.3.2-9b099619e5c5c8370254862105ad69cf154d7cf6e4baeb0b9983c7c55ab3c623

➜  Yampa-Front git:(master) ✗ ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.2.2

[dpwiz]

I copypasted your example and can see the keyboard (mouse, etc.) events in console.

But I had to add threadDelay 100000 before polling or else I'm getting flooded with [] messages.
(setting defaultRenderer {rendererType = AcceleratedVSyncRenderer} also works).

I'm in ubuntu though, with

Package: libsdl2-dev
Version: 2.0.14+dfsg2-3

[dpwiz]

I managed to build and link with 2.0.20 too and is able to quit with the q.

[dpwiz]

@EMQ-YangM Do you have it working now?

[abbradar]

I have the same issue -- in the recent update pollEvents stopped working, always returning an empty list. I use OpenGL only, without SDL.Video.Renderer. SDL 2.0.20 and sdl2 2.5.3.0.

[abbradar]

I found #242 and indeed, bumping sdl2 to 2.5.3.2 solved the issue.