From c12a152ec972309a87ab1637091990520ce9c123 Mon Sep 17 00:00:00 2001
From: Patric Stout <truebrain@openttd.org>
Date: Thu, 17 Jun 2021 18:58:59 +0200
Subject: [PATCH] Fix: thread safety issue during exiting the game (#9380)

_exit_game is read by the draw-thread to know when to exit, but
most of the time written by the game-thread.
---
 src/gfx.cpp   | 2 +-
 src/openttd.h | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/gfx.cpp b/src/gfx.cpp
index d787dc26f6..ff2c80bfc0 100644
--- a/src/gfx.cpp
+++ b/src/gfx.cpp
@@ -41,7 +41,7 @@ bool _right_button_down;    ///< Is right mouse button pressed?
 bool _right_button_clicked; ///< Is right mouse button clicked?
 DrawPixelInfo _screen;
 bool _screen_disable_anim = false;   ///< Disable palette animation (important for 32bpp-anim blitter during giant screenshot)
-bool _exit_game;
+std::atomic<bool> _exit_game;
 GameMode _game_mode;
 SwitchMode _switch_mode;  ///< The next mainloop command.
 PauseMode _pause_mode;
diff --git a/src/openttd.h b/src/openttd.h
index 2cd9cc1f09..6473168ee1 100644
--- a/src/openttd.h
+++ b/src/openttd.h
@@ -10,6 +10,7 @@
 #ifndef OPENTTD_H
 #define OPENTTD_H
 
+#include <atomic>
 #include "core/enum_type.hpp"
 
 /** Mode which defines the state of the game. */
@@ -52,7 +53,7 @@ enum DisplayOptions {
 
 extern GameMode _game_mode;
 extern SwitchMode _switch_mode;
-extern bool _exit_game;
+extern std::atomic<bool> _exit_game;
 extern bool _save_config;
 
 /** Modes of pausing we've got */