Remove default empty state of sf::Event

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -57,9 +57,9 @@ body:
 
                   while (window.isOpen())
                   {
-                      while (const auto event = window.pollEvent())
+                      while (const std::optional event = window.pollEvent())
                       {
-                          if (event.is<sf::Event::Closed>())
+                          if (event->is<sf::Event::Closed>())
                               window.close();
                       }
 

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -54,9 +54,9 @@ body:
 
                   while (window.isOpen())
                   {
-                      while (const auto event = window.pollEvent())
+                      while (const std::optional event = window.pollEvent())
                       {
-                          if (event.is<sf::Event::Closed>())
+                          if (event->is<sf::Event::Closed>())
                               window.close();
                       }
 

.github/pull_request_template.md

@@ -39,9 +39,9 @@ int main()
 
     while (window.isOpen())
     {
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
-            if (event.is<sf::Event::Closed>())
+            if (event->is<sf::Event::Closed>())
                 window.close();
         }
 

doc/mainpage.hpp

@@ -38,10 +38,10 @@
 ///     while (window.isOpen())
 ///     {
 ///         // Process events
-///         while (const auto event = window.pollEvent())
+///         while (const std::optional event = window.pollEvent())
 ///         {
 ///             // Close window: exit
-///             if (event.is<sf::Event::Closed>())
+///             if (event->is<sf::Event::Closed>())
 ///                 window.close();
 ///         }
 ///

examples/android/app/src/main/jni/main.cpp

@@ -109,43 +109,41 @@ int main(int argc, char* argv[])
 
     while (window.isOpen())
     {
-        while (const auto event = active ? window.pollEvent() : window.waitEvent())
+        while (const std::optional event = active ? window.pollEvent() : window.waitEvent())
         {
-            if (event.is<sf::Event::Closed>())
+            if (event->is<sf::Event::Closed>() ||
+                (event->is<sf::Event::KeyPressed>() &&
+                 event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
             {
                 window.close();
             }
-            else if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>())
+
-            {
+            else if (const auto* resized = event->getIf<sf::Event::Resized>())
-                if (keyPressed->code == sf::Keyboard::Key::Escape)
-                    window.close();
-            }
-            else if (const auto* resized = event.getIf<sf::Event::Resized>())
             {
                 const auto size = sf::Vector2f(resized->size);
                 view.setSize(size);
                 view.setCenter(size / 2.f);
                 window.setView(view);
             }
-            else if (event.is<sf::Event::FocusLost>())
+            else if (event->is<sf::Event::FocusLost>())
             {
                 background = sf::Color::Black;
             }
-            else if (event.is<sf::Event::FocusGained>())
+            else if (event->is<sf::Event::FocusGained>())
             {
                 background = sf::Color::White;
             }
             // On Android MouseLeft/MouseEntered are (for now) triggered,
             // whenever the app loses or gains focus.
-            else if (event.is<sf::Event::MouseLeft>())
+            else if (event->is<sf::Event::MouseLeft>())
             {
                 active = false;
             }
-            else if (event.is<sf::Event::MouseEntered>())
+            else if (event->is<sf::Event::MouseEntered>())
             {
                 active = true;
             }
-            else if (const auto* touchBegan = event.getIf<sf::Event::TouchBegan>())
+            else if (const auto* touchBegan = event->getIf<sf::Event::TouchBegan>())
             {
                 if (touchBegan->finger == 0)
                 {

examples/island/Island.cpp

@@ -174,20 +174,21 @@ int main()
     while (window.isOpen())
     {
         // Handle events
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
             // Window closed or escape key pressed: exit
-            if (event.is<sf::Event::Closed>() || (event.is<sf::Event::KeyPressed>() &&
+            if (event->is<sf::Event::Closed>() ||
-                                                  event.getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
+                (event->is<sf::Event::KeyPressed>() &&
+                 event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
             {
                 window.close();
                 break;
             }
 
             // Arrow key pressed:
-            if (terrainShader.has_value() && event.is<sf::Event::KeyPressed>())
+            if (terrainShader.has_value() && event->is<sf::Event::KeyPressed>())
             {
-                switch (event.getIf<sf::Event::KeyPressed>()->code)
+                switch (event->getIf<sf::Event::KeyPressed>()->code)
                 {
                     case sf::Keyboard::Key::Enter:
                         generateTerrain(terrainStagingBuffer.data());

examples/joystick/Joystick.cpp

@@ -156,36 +156,38 @@ int main()
     while (window.isOpen())
     {
         // Handle events
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
             // Window closed or escape key pressed: exit
-            if (event.is<sf::Event::Closed>() || (event.is<sf::Event::KeyPressed>() &&
+            if (event->is<sf::Event::Closed>() ||
-                                                  event.getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
+                (event->is<sf::Event::KeyPressed>() &&
+                 event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
             {
                 window.close();
                 break;
             }
-            else if (const auto* joystickButtonPressed = event.getIf<sf::Event::JoystickButtonPressed>())
+
+            if (const auto* joystickButtonPressed = event->getIf<sf::Event::JoystickButtonPressed>())
             {
                 // Update displayed joystick values
                 updateValues(joystickButtonPressed->joystickId);
             }
-            else if (const auto* joystickButtonReleased = event.getIf<sf::Event::JoystickButtonReleased>())
+            else if (const auto* joystickButtonReleased = event->getIf<sf::Event::JoystickButtonReleased>())
             {
                 // Update displayed joystick values
                 updateValues(joystickButtonReleased->joystickId);
             }
-            else if (const auto* joystickMoved = event.getIf<sf::Event::JoystickMoved>())
+            else if (const auto* joystickMoved = event->getIf<sf::Event::JoystickMoved>())
             {
                 // Update displayed joystick values
                 updateValues(joystickMoved->joystickId);
             }
-            else if (const auto* joystickConnected = event.getIf<sf::Event::JoystickConnected>())
+            else if (const auto* joystickConnected = event->getIf<sf::Event::JoystickConnected>())
             {
                 // Update displayed joystick values
                 updateValues(joystickConnected->joystickId);
             }
-            else if (event.is<sf::Event::JoystickDisconnected>())
+            else if (event->is<sf::Event::JoystickDisconnected>())
             {
                 // Reset displayed joystick values to empty
                 for (auto& [label, joystickObject] : texts)

examples/opengl/OpenGL.cpp

@@ -201,25 +201,19 @@ int main()
         while (window.isOpen())
         {
             // Process events
-            while (const auto event = window.pollEvent())
+            while (const std::optional event = window.pollEvent())
             {
-                // Close window: exit
+                // Window closed or escape key pressed: exit
-                if (event.is<sf::Event::Closed>())
+                if (event->is<sf::Event::Closed>() ||
-                {
+                    (event->is<sf::Event::KeyPressed>() &&
-                    exit = true;
+                     event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
-                    window.close();
-                }
-
-                // Escape key: exit
-                if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>();
-                    keyPressed && keyPressed->code == sf::Keyboard::Key::Escape)
                 {
                     exit = true;
                     window.close();
                 }
 
                 // Return key: toggle mipmapping
-                if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>();
+                if (const auto* keyPressed = event->getIf<sf::Event::KeyPressed>();
                     keyPressed && keyPressed->code == sf::Keyboard::Key::Enter)
                 {
                     if (mipmapEnabled)
@@ -236,7 +230,7 @@ int main()
                 }
 
                 // Space key: toggle sRGB conversion
-                if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>();
+                if (const auto* keyPressed = event->getIf<sf::Event::KeyPressed>();
                     keyPressed && keyPressed->code == sf::Keyboard::Key::Space)
                 {
                     sRgb = !sRgb;
@@ -244,7 +238,7 @@ int main()
                 }
 
                 // Adjust the viewport when the window is resized
-                if (const auto* resized = event.getIf<sf::Event::Resized>())
+                if (const auto* resized = event->getIf<sf::Event::Resized>())
                 {
                     const sf::Vector2u textureSize = backgroundTexture.getSize();
 

examples/raw_input/RawInput.cpp

@@ -34,9 +34,9 @@ int main()
 
     while (window.isOpen())
     {
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
-            if (event.is<sf::Event::Closed>())
+            if (event->is<sf::Event::Closed>())
             {
                 window.close();
                 break;
@@ -45,10 +45,10 @@ int main()
             static const auto vec2ToString = [](const sf::Vector2i& vec2)
             { return '(' + std::to_string(vec2.x) + ", " + std::to_string(vec2.y) + ')'; };
 
-            if (const auto* const mouseMoved = event.getIf<sf::Event::MouseMoved>())
+            if (const auto* const mouseMoved = event->getIf<sf::Event::MouseMoved>())
                 mousePosition.setString("Mouse Position: " + vec2ToString(mouseMoved->position));
 
-            if (const auto* const mouseMovedRaw = event.getIf<sf::Event::MouseMovedRaw>())
+            if (const auto* const mouseMovedRaw = event->getIf<sf::Event::MouseMovedRaw>())
             {
                 log.emplace_back("Mouse Movement: " + vec2ToString(mouseMovedRaw->delta));
 

examples/shader/Shader.cpp

@@ -438,16 +438,16 @@ int main()
     while (window.isOpen())
     {
         // Process events
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
             // Close window: exit
-            if (event.is<sf::Event::Closed>())
+            if (event->is<sf::Event::Closed>())
             {
                 window.close();
                 break;
             }
 
-            if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>())
+            if (const auto* keyPressed = event->getIf<sf::Event::KeyPressed>())
             {
                 switch (keyPressed->code)
                 {

examples/sound_effects/SoundEffects.cpp

@@ -1124,13 +1124,13 @@ int main()
     while (window.isOpen())
     {
         // Process events
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
             // Close window: exit
-            if (event.is<sf::Event::Closed>())
+            if (event->is<sf::Event::Closed>())
                 window.close();
 
-            if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>())
+            if (const auto* keyPressed = event->getIf<sf::Event::KeyPressed>())
             {
                 switch (keyPressed->code)
                 {

examples/stencil/Stencil.cpp

@@ -40,10 +40,10 @@ int main()
     while (window.isOpen())
     {
         // Handle events
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
             // Window closed: exit
-            if (event.is<sf::Event::Closed>())
+            if (event->is<sf::Event::Closed>())
             {
                 window.close();
                 break;

examples/tennis/Tennis.cpp

@@ -109,19 +109,21 @@ int main()
     while (window.isOpen())
     {
         // Handle events
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
         {
             // Window closed or escape key pressed: exit
-            if (event.is<sf::Event::Closed>() || (event.is<sf::Event::KeyPressed>() &&
+            if (event->is<sf::Event::Closed>() ||
-                                                  event.getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
+                (event->is<sf::Event::KeyPressed>() &&
+                 event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
             {
                 window.close();
                 break;
             }
 
             // Space key pressed: play
-            if ((event.is<sf::Event::KeyPressed>() && event.getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Space) ||
+            if ((event->is<sf::Event::KeyPressed>() &&
-                event.is<sf::Event::TouchBegan>())
+                 event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Space) ||
+                event->is<sf::Event::TouchBegan>())
             {
                 if (!isPlaying)
                 {
@@ -144,7 +146,7 @@ int main()
             }
 
             // Window size changed, adjust view appropriately
-            if (event.is<sf::Event::Resized>())
+            if (event->is<sf::Event::Resized>())
             {
                 sf::View view;
                 view.setSize({gameWidth, gameHeight});

examples/vulkan/Vulkan.cpp

@@ -2544,19 +2544,18 @@ public:
         while (window.isOpen())
         {
             // Process events
-            while (const auto event = window.pollEvent())
+            while (const std::optional event = window.pollEvent())
+            {
+                // Window closed or escape key pressed: exit
+                if (event->is<sf::Event::Closed>() ||
+                    (event->is<sf::Event::KeyPressed>() &&
+                     event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
                 {
-                // Close window: exit
-                if (event.is<sf::Event::Closed>())
-                    window.close();
-
-                // Escape key: exit
-                if (event.is<sf::Event::KeyPressed>() &&
-                    event.getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape)
                     window.close();
+                }
 
                 // Re-create the swapchain when the window is resized
-                if (event.is<sf::Event::Resized>())
+                if (event->is<sf::Event::Resized>())
                     swapchainOutOfDate = true;
             }
 

examples/window/Window.cpp

@@ -141,19 +141,18 @@ int main()
     while (window.isOpen())
     {
         // Process events
-        while (const auto event = window.pollEvent())
+        while (const std::optional event = window.pollEvent())
+        {
+            // Window closed or escape key pressed: exit
+            if (event->is<sf::Event::Closed>() ||
+                (event->is<sf::Event::KeyPressed>() &&
+                 event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
             {
-            // Close window: exit
-            if (event.is<sf::Event::Closed>())
-                window.close();
-
-            // Escape key: exit
-            if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>())
-                if (keyPressed->code == sf::Keyboard::Key::Escape)
                 window.close();
+            }
 
             // Resize event: adjust the viewport
-            if (const auto* resized = event.getIf<sf::Event::Resized>())
+            if (const auto* resized = event->getIf<sf::Event::Resized>())
             {
                 const auto [width, height] = resized->size;
                 glViewport(0, 0, static_cast<GLsizei>(width), static_cast<GLsizei>(height));

include/SFML/Graphics/RenderWindow.hpp

@@ -237,10 +237,10 @@ private:
 /// while (window.isOpen())
 /// {
 ///    // Event processing
-///    while (const auto event = window.pollEvent())
+///    while (const std::optional event = window.pollEvent())
 ///    {
 ///        // Request for closing the window
-///        if (event.is<sf::Event::Closed>())
+///        if (event->is<sf::Event::Closed>())
 ///            window.close();
 ///    }
 ///

include/SFML/Window/Clipboard.hpp

@@ -91,11 +91,12 @@ SFML_WINDOW_API void setString(const String& text);
 /// sf::String string = sf::Clipboard::getString();
 ///
 /// // or use it in the event loop
-/// while (const auto event = window.pollEvent())
+/// while (const std::optional event = window.pollEvent())
 /// {
-///     if(event.is<sf::Event::Closed>())
+///     if (event->is<sf::Event::Closed>())
 ///         window.close();
-///     if(const auto* keyPressed = event.getIf<sf::Event::KeyPressed>())
+///
+///     if (const auto* keyPressed = event->getIf<sf::Event::KeyPressed>())
 ///     {
 ///         // Using Ctrl + V to paste a string into SFML
 ///         if (keyPressed->control && keyPressed->code == sf::Keyboard::Key::V)

include/SFML/Window/Event.hpp

@@ -48,14 +48,6 @@ namespace sf
 class SFML_WINDOW_API Event
 {
 public:
-    ////////////////////////////////////////////////////////////
-    /// \brief Empty event
-    ///
-    ////////////////////////////////////////////////////////////
-    struct Empty
-    {
-    };
-
     ////////////////////////////////////////////////////////////
     /// \brief Closed event
     ///
@@ -274,14 +266,6 @@ public:
         Vector3f     value;  //!< Current value of the sensor on the X, Y, and Z axes
     };
 
-    ////////////////////////////////////////////////////////////
-    /// \brief Default constructor
-    ///
-    /// Sets the event to sf::Event::Empty
-    ///
-    ////////////////////////////////////////////////////////////
-    Event() = default;
-
     ////////////////////////////////////////////////////////////
     /// \brief Construct from a given sf::Event subtype
     ///
@@ -309,23 +293,11 @@ public:
     template <typename T>
     [[nodiscard]] const T* getIf() const;
 
-    ////////////////////////////////////////////////////////////
-    /// \brief Check if current event type is not `Empty`
-    ///
-    /// \return True if current event type is not `Empty`
-    ///
-    ////////////////////////////////////////////////////////////
-    [[nodiscard]] explicit operator bool() const
-    {
-        return !is<Empty>();
-    }
-
 private:
     ////////////////////////////////////////////////////////////
     // Member data
     ////////////////////////////////////////////////////////////
-    std::variant<Empty,
+    std::variant<Closed,
-                 Closed,
                  Resized,
                  FocusLost,
                  FocusGained,
@@ -390,19 +362,16 @@ private:
 /// any of the corresponding event data.
 ///
 /// \code
-/// while (const auto event = window.pollEvent())
+/// while (const std::optional event = window.pollEvent())
 /// {
-///     // Request for closing the window
+///     // Window closed or escape key pressed: exit
-///     if (event.is<sf::Event::Closed>())
+///     if (event->is<sf::Event::Closed>() ||
-///         window.close();
+///         (event->is<sf::Event::KeyPressed>() &&
-///
+///          event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
-///     // The escape key was pressed
-///     if (const auto* keyPressed = event.getIf<sf::Event::KeyPressed>())
-///         if (keyPressed->code == sf::Keyboard::Key::Escape)
 ///         window.close();
 ///
 ///     // The window was resized
-///     if (const auto* resized = event.getIf<sf::Event::Resized>())
+///     if (const auto* resized = event->getIf<sf::Event::Resized>())
 ///         doSomethingWithTheNewSize(resized->size);
 ///
 ///     // etc ...

include/SFML/Window/Window.hpp

@@ -347,10 +347,10 @@ private:
 /// while (window.isOpen())
 /// {
 ///    // Event processing
-///    while (const auto event = window.pollEvent())
+///    while (const std::optional event = window.pollEvent())
 ///    {
 ///        // Request for closing the window
-///        if (event.is<sf::Event::Closed>())
+///        if (event->is<sf::Event::Closed>())
 ///            window.close();
 ///    }
 ///

include/SFML/Window/WindowBase.hpp

@@ -181,36 +181,36 @@ public:
     /// \brief Pop the next event from the front of the FIFO event queue, if any, and return it
     ///
     /// This function is not blocking: if there's no pending event then
-    /// it will return an empty event. Note that more than one event
+    /// it will return a `std::nullopt`. Note that more than one event
     /// may be present in the event queue, thus you should always call
     /// this function in a loop to make sure that you process every
     /// pending event.
     /// \code
-    /// while (const auto event = window.pollEvent())
+    /// while (const std::optional event = window.pollEvent())
     /// {
     ///    // process event...
     /// }
     /// \endcode
     ///
-    /// \return The event; will be `Empty` (convertible to `false`) if no events are pending
+    /// \return The event, otherwise `std::nullopt` if no events are pending
     ///
     /// \see waitEvent
     ///
     ////////////////////////////////////////////////////////////
-    [[nodiscard]] Event pollEvent();
+    [[nodiscard]] std::optional<Event> pollEvent();
 
     ////////////////////////////////////////////////////////////
     /// \brief Wait for an event and return it
     ///
     /// This function is blocking: if there's no pending event then
     /// it will wait until an event is received or until the provided
-    /// timeout elapses. After this function returns if no error nor
+    /// timeout elapses. Only if an error or a timeout occurs the
-    /// timeout occurred, the returned event will not be empty.
+    /// returned event will be `std::nullopt`.
     /// This function is typically used when you have a thread that is
     /// dedicated to events handling: you want to make this thread sleep
     /// as long as no new event is received.
     /// \code
-    /// if (const auto event = window.waitEvent())
+    /// while (const std::optional event = window.waitEvent())
     /// {
     ///    // process event...
     /// }
@@ -218,12 +218,12 @@ public:
     ///
     /// \param timeout Maximum time to wait (`Time::Zero` for infinite)
     ///
-    /// \return The event; will be `Empty` (convertible to `false`) on timeout or if window was closed
+    /// \return The event, otherwise `std::nullopt` on timeout or if window was closed
     ///
     /// \see pollEvent
     ///
     ////////////////////////////////////////////////////////////
-    [[nodiscard]] Event waitEvent(Time timeout = Time::Zero);
+    [[nodiscard]] std::optional<Event> waitEvent(Time timeout = Time::Zero);
 
     ////////////////////////////////////////////////////////////
     /// \brief Get the position of the window
@@ -561,10 +561,10 @@ private:
 /// while (window.isOpen())
 /// {
 ///    // Event processing
-///    while (const auto event = window.pollEvent())
+///    while (const std::optional event = window.pollEvent())
 ///    {
 ///        // Request for closing the window
-///        if (event.is<sf::Event::Closed>())
+///        if (event->is<sf::Event::Closed>())
 ///            window.close();
 ///    }
 ///

src/SFML/Window/Android/WindowImplAndroid.cpp

@@ -463,27 +463,19 @@ int WindowImplAndroid::processKeyEvent(AInputEvent* inputEvent, ActivityStates&
 int WindowImplAndroid::processMotionEvent(AInputEvent* inputEvent, ActivityStates& states)
 {
     const std::int32_t device       = AInputEvent_getSource(inputEvent);
-
-    Event event;
-
-    if (device == AINPUT_SOURCE_MOUSE)
-        event = Event::MouseMoved{};
-    else if (static_cast<std::uint32_t>(device) & AINPUT_SOURCE_TOUCHSCREEN)
-        event = Event::TouchMoved{};
-
     const std::size_t  pointerCount = AMotionEvent_getPointerCount(inputEvent);
 
     for (std::size_t p = 0; p < pointerCount; ++p)
     {
         const std::int32_t id = AMotionEvent_getPointerId(inputEvent, p);
 
-        int x = static_cast<int>(AMotionEvent_getX(inputEvent, p));
+        const int x = static_cast<int>(AMotionEvent_getX(inputEvent, p));
-        int y = static_cast<int>(AMotionEvent_getY(inputEvent, p));
+        const int y = static_cast<int>(AMotionEvent_getY(inputEvent, p));
 
         if (device == AINPUT_SOURCE_MOUSE)
         {
             const Event::MouseMoved mouseMoved{{x, y}};
-            event = mouseMoved;
+            forwardEvent(mouseMoved);
 
             states.mousePosition = mouseMoved.position;
         }
@@ -493,13 +485,12 @@ int WindowImplAndroid::processMotionEvent(AInputEvent* inputEvent, ActivityState
                 continue;
 
             const Event::TouchMoved touchMoved{static_cast<unsigned int>(id), {x, y}};
-            event = touchMoved;
+            forwardEvent(touchMoved);
 
             states.touchEvents[id] = touchMoved.position;
         }
-
-        forwardEvent(event);
     }
+
     return 1;
 }
 
@@ -517,45 +508,42 @@ int WindowImplAndroid::processPointerEvent(bool isDown, AInputEvent* inputEvent,
     int x = static_cast<int>(AMotionEvent_getX(inputEvent, index));
     int y = static_cast<int>(AMotionEvent_getY(inputEvent, index));
 
-    Event event;
-
     if (isDown)
     {
         if (device == AINPUT_SOURCE_MOUSE)
         {
-            event = Event::MouseButtonPressed{button, {x, y}};
-
             if (id >= 0 && id < static_cast<int>(Mouse::ButtonCount))
                 states.isButtonPressed[button] = true;
+
+            forwardEvent(Event::MouseButtonPressed{button, {x, y}});
         }
         else if (static_cast<unsigned int>(device) & AINPUT_SOURCE_TOUCHSCREEN)
         {
             Event::TouchBegan touchBegan;
             touchBegan.finger   = static_cast<unsigned int>(id);
             touchBegan.position = {x, y};
-            event               = touchBegan;
 
             states.touchEvents[id] = touchBegan.position;
+
+            forwardEvent(touchBegan);
         }
     }
     else
     {
         if (device == AINPUT_SOURCE_MOUSE)
         {
-            event = Event::MouseButtonReleased{button, {x, y}};
-
             if (id >= 0 && id < static_cast<int>(Mouse::ButtonCount))
                 states.isButtonPressed[button] = false;
+
+            forwardEvent(Event::MouseButtonReleased{button, {x, y}});
         }
         else if (static_cast<std::uint32_t>(device) & AINPUT_SOURCE_TOUCHSCREEN)
         {
-            event = Event::TouchEnded{static_cast<unsigned int>(id), {x, y}};
-
             states.touchEvents.erase(id);
+            forwardEvent(Event::TouchEnded{static_cast<unsigned int>(id), {x, y}});
         }
     }
 
-    forwardEvent(event);
     return 1;
 }
 

src/SFML/Window/DRM/InputImpl.cpp

@@ -341,7 +341,7 @@ void processSlots()
     }
 }
 
-bool eventProcess(sf::Event& event)
+std::optional<sf::Event> eventProcess()
 {
     const std::lock_guard lock(inputMutex);
 
@@ -353,9 +353,10 @@ bool eventProcess(sf::Event& event)
     static unsigned int doDeferredText = 0;
     if (doDeferredText)
     {
-        event          = sf::Event::TextEntered{doDeferredText};
+        const auto event = sf::Event::TextEntered{doDeferredText};
+
         doDeferredText = 0;
-        return true;
+        return event;
     }
 
     ssize_t bytesRead = 0;
@@ -372,13 +373,12 @@ bool eventProcess(sf::Event& event)
             {
                 if (const std::optional<sf::Mouse::Button> mb = toMouseButton(inputEvent.code))
                 {
-                    if (inputEvent.value)
-                        event = sf::Event::MouseButtonPressed{*mb, mousePos};
-                    else
-                        event = sf::Event::MouseButtonReleased{*mb, mousePos};
-
                     mouseMap[*mb] = inputEvent.value;
-                    return true;
+
+                    if (inputEvent.value)
+                        return sf::Event::MouseButtonPressed{*mb, mousePos};
+                    else
+                        return sf::Event::MouseButtonReleased{*mb, mousePos};
                 }
                 else
                 {
@@ -394,8 +394,7 @@ bool eventProcess(sf::Event& event)
                         //
                         if (special)
                         {
-                            event = sf::Event::TextEntered{special};
+                            return sf::Event::TextEntered{special};
-                            return true;
                         }
                     }
                     else if (kb != sf::Keyboard::Key::Unknown)
@@ -410,17 +409,15 @@ bool eventProcess(sf::Event& event)
                         keyChanged.shift    = shiftDown();
                         keyChanged.system   = systemDown();
 
-                        if (inputEvent.value)
-                            event = sf::Event::KeyPressed{keyChanged};
-                        else
-                            event = sf::Event::KeyReleased{keyChanged};
-
                         keyMap[kb] = inputEvent.value;
 
                         if (special && inputEvent.value)
                             doDeferredText = special;
 
-                        return true;
+                        if (inputEvent.value)
+                            return sf::Event::KeyPressed{keyChanged};
+                        else
+                            return sf::Event::KeyReleased{keyChanged};
                     }
                 }
             }
@@ -443,14 +440,11 @@ bool eventProcess(sf::Event& event)
                         sf::Event::MouseWheelScrolled mouseWheelScrolled;
                         mouseWheelScrolled.delta    = static_cast<float>(inputEvent.value);
                         mouseWheelScrolled.position = mousePos;
-                        event                       = mouseWheelScrolled;
+                        return mouseWheelScrolled;
-                        return true;
                 }
-
                 if (posChange)
                 {
-                    event = sf::Event::MouseMoved{mousePos};
+                    return sf::Event::MouseMoved{mousePos};
-                    return true;
                 }
             }
             else if (inputEvent.type == EV_ABS)
@@ -488,7 +482,6 @@ bool eventProcess(sf::Event& event)
         if ((bytesRead < 0) && (errno != EAGAIN))
             sf::err() << " Error: " << std::strerror(errno) << std::endl;
     }
-
     // Finally check if there is a Text event on stdin
     //
     // We only clear the ICANON flag for the time of reading
@@ -534,22 +527,18 @@ bool eventProcess(sf::Event& event)
     if (code > 0)
     {
         // TODO: Proper unicode handling
-        event = sf::Event::TextEntered{code};
+        return sf::Event::TextEntered{code};
-        return true;
     }
 
     // No events available
-    return false;
+    return std::nullopt;
 }
 
 // assumes inputMutex is locked
 void update()
 {
-    sf::Event event;
+    while (const std::optional event = eventProcess())
-    while (eventProcess(event))
+        pushEvent(*event);
-    {
-        pushEvent(event);
-    }
 }
 } // namespace
 
@@ -603,7 +592,7 @@ String getDescription(Keyboard::Scancode /* code */)
 }
 
 
-////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////
 void setVirtualKeyboardVisible(bool /*visible*/)
 {
     // Not applicable
@@ -682,36 +671,35 @@ Vector2i getTouchPosition(unsigned int finger, const WindowBase& /*relativeTo*/)
 
 
 ////////////////////////////////////////////////////////////
-bool checkEvent(Event& event)
+std::optional<Event> checkEvent()
 {
     const std::lock_guard lock(inputMutex);
+
     if (!eventQueue.empty())
     {
-        event = eventQueue.front();
+        auto event = std::make_optional(eventQueue.front());
         eventQueue.pop();
 
-        return true;
+        return event;
     }
 
-    if (eventProcess(event))
+    if (const std::optional event = eventProcess())
     {
-        return true;
+        return event;
     }
-    else
+
-    {
     // In the case of multitouch, eventProcess() could have returned false
     // but added events directly to the queue.  (This is ugly, but I'm not
     // sure of a good way to handle generating multiple events at once.)
     if (!eventQueue.empty())
     {
-            event = eventQueue.front();
+        auto event = std::make_optional(eventQueue.front());
         eventQueue.pop();
 
-            return true;
+        return event;
-        }
     }
 
-    return false;
+    return std::nullopt;
 }
 
 

src/SFML/Window/DRM/WindowImplDRM.cpp

@@ -46,7 +46,7 @@ namespace InputImpl
 /// \return False if event queue is empty
 ///
 ////////////////////////////////////////////////////////////
-bool checkEvent(Event& event);
+std::optional<Event> checkEvent();
 
 ////////////////////////////////////////////////////////////
 /// \brief Backup terminal configuration and disable console feedback
@@ -190,9 +190,8 @@ bool WindowImplDRM::hasFocus() const
 
 void WindowImplDRM::processEvents()
 {
-    Event event;
+    while (const std::optional event = InputImpl::checkEvent())
-    while (InputImpl::checkEvent(event))
+        pushEvent(*event);
-        pushEvent(event);
 }
 
 } // namespace sf::priv

src/SFML/Window/WindowBase.cpp

@@ -43,6 +43,7 @@
 #include <vector>
 
 #include <cassert>
+#include <cstdlib>
 
 
 namespace
@@ -71,7 +72,7 @@ WindowBase::WindowBase(VideoMode mode, const String& title, std::uint32_t style,
 ////////////////////////////////////////////////////////////
 WindowBase::WindowBase(VideoMode mode, const String& title, State state)
 {
-    WindowBase::create(mode, title, sf::Style::Default, state);
+    WindowBase::create(mode, title, Style::Default, state);
 }
 
 
@@ -146,21 +147,35 @@ bool WindowBase::isOpen() const
 
 
 ////////////////////////////////////////////////////////////
-Event WindowBase::pollEvent()
+std::optional<Event> WindowBase::pollEvent()
 {
-    Event event;
+    std::optional<sf::Event> event; // Use a single local variable for NRVO
-    if (m_impl && (event = m_impl->pollEvent()))
+
-        filterEvent(event);
+    if (m_impl == nullptr)
+        return event; // Empty optional
+
+    event = m_impl->pollEvent();
+
+    if (event.has_value())
+        filterEvent(*event);
+
     return event;
 }
 
 
 ////////////////////////////////////////////////////////////
-Event WindowBase::waitEvent(Time timeout)
+std::optional<Event> WindowBase::waitEvent(Time timeout)
 {
-    Event event;
+    std::optional<sf::Event> event; // Use a single local variable for NRVO
-    if (m_impl && (event = m_impl->waitEvent(timeout)))
+
-        filterEvent(event);
+    if (m_impl == nullptr)
+        return event; // Empty optional
+
+    event = m_impl->waitEvent(timeout);
+
+    if (event.has_value())
+        filterEvent(*event);
+
     return event;
 }
 

src/SFML/Window/WindowImpl.cpp

@@ -176,7 +176,7 @@ void WindowImpl::setMaximumSize(const std::optional<Vector2u>& maximumSize)
 
 
 ////////////////////////////////////////////////////////////
-Event WindowImpl::waitEvent(Time timeout)
+std::optional<Event> WindowImpl::waitEvent(Time timeout)
 {
     const auto timedOut = [&, startTime = std::chrono::steady_clock::now()]
     {
@@ -201,7 +201,7 @@ Event WindowImpl::waitEvent(Time timeout)
 
 
 ////////////////////////////////////////////////////////////
-Event WindowImpl::pollEvent()
+std::optional<Event> WindowImpl::pollEvent()
 {
     // If the event queue is empty, let's first check if new events are available from the OS
     if (m_events.empty())
@@ -212,13 +212,13 @@ Event WindowImpl::pollEvent()
 
 
 ////////////////////////////////////////////////////////////
-Event WindowImpl::popEvent()
+std::optional<Event> WindowImpl::popEvent()
 {
-    Event event;
+    std::optional<Event> event; // Use a single local variable for NRVO
 
     if (!m_events.empty())
     {
-        event = m_events.front();
+        event.emplace(m_events.front());
         m_events.pop();
     }
 

src/SFML/Window/WindowImpl.hpp

@@ -129,10 +129,10 @@ public:
     ///
     /// \param timeout Maximum time to wait (`Time::Zero` for infinite)
     ///
-    /// \return The event on success, `Event::Empty` otherwise
+    /// \return The event on success, `std::nullopt` otherwise
     ///
     ////////////////////////////////////////////////////////////
-    [[nodiscard]] Event waitEvent(Time timeout);
+    [[nodiscard]] std::optional<Event> waitEvent(Time timeout);
 
     ////////////////////////////////////////////////////////////
     /// \brief Return the next window event, if available
@@ -140,10 +140,10 @@ public:
     /// If there's no event available, this function calls the
     /// window's internal event processing function.
     ///
-    /// \return The event if available, `Event::Empty` otherwise
+    /// \return The event if available, `std::nullopt` otherwise
     ///
     ////////////////////////////////////////////////////////////
-    [[nodiscard]] Event pollEvent();
+    [[nodiscard]] std::optional<Event> pollEvent();
 
     ////////////////////////////////////////////////////////////
     /// \brief Get the OS-specific handle of the window
@@ -334,10 +334,10 @@ private:
     struct JoystickStatesImpl;
 
     ////////////////////////////////////////////////////////////
-    /// \brief Pop the first event of the queue if available, otherwise an empty event
+    /// \return First event of the queue if available, `std::nullopt` otherwise
     ///
     ////////////////////////////////////////////////////////////
-    [[nodiscard]] Event popEvent();
+    [[nodiscard]] std::optional<Event> popEvent();
 
     ////////////////////////////////////////////////////////////
     /// \brief Read the joysticks state and generate the appropriate events

test/Window/Event.test.cpp

@@ -8,6 +8,7 @@ TEST_CASE("[Window] sf::Event")
 {
     SECTION("Type traits")
     {
+        STATIC_CHECK(!std::is_default_constructible_v<sf::Event>);
         STATIC_CHECK(std::is_copy_constructible_v<sf::Event>);
         STATIC_CHECK(std::is_copy_assignable_v<sf::Event>);
         STATIC_CHECK(std::is_nothrow_move_constructible_v<sf::Event>);
@@ -16,18 +17,9 @@ TEST_CASE("[Window] sf::Event")
 
     SECTION("Construction")
     {
-        SECTION("Default constructor")
-        {
-            const sf::Event event;
-            CHECK(!event);
-            CHECK(event.is<sf::Event::Empty>());
-            CHECK(event.getIf<sf::Event::Empty>());
-        }
-
         SECTION("Template constructor")
         {
             const sf::Event event = sf::Event::Resized{{1, 2}};
-            CHECK(event);
             CHECK(event.is<sf::Event::Resized>());
             CHECK(event.getIf<sf::Event::Resized>());
             const auto& resized = *event.getIf<sf::Event::Resized>();
@@ -37,38 +29,31 @@ TEST_CASE("[Window] sf::Event")
 
     SECTION("Assign all possible values")
     {
-        sf::Event event;
+        sf::Event event = sf::Event::Closed{};
-        event = sf::Event::Closed{};
-        CHECK(event);
         CHECK(event.is<sf::Event::Closed>());
         CHECK(event.getIf<sf::Event::Closed>());
 
         event = sf::Event::Resized{{1, 2}};
-        CHECK(event);
         CHECK(event.is<sf::Event::Resized>());
         CHECK(event.getIf<sf::Event::Resized>());
         const auto& resized = *event.getIf<sf::Event::Resized>();
         CHECK(resized.size == sf::Vector2u(1, 2));
 
         event = sf::Event::FocusLost{};
-        CHECK(event);
         CHECK(event.is<sf::Event::FocusLost>());
         CHECK(event.getIf<sf::Event::FocusLost>());
 
         event = sf::Event::FocusGained{};
-        CHECK(event);
         CHECK(event.is<sf::Event::FocusGained>());
         CHECK(event.getIf<sf::Event::FocusGained>());
 
         event = sf::Event::TextEntered{123456};
-        CHECK(event);
         CHECK(event.is<sf::Event::TextEntered>());
         CHECK(event.getIf<sf::Event::TextEntered>());
         const auto& textEntered = *event.getIf<sf::Event::TextEntered>();
         CHECK(textEntered.unicode == 123456);
 
         event = sf::Event::KeyPressed{sf::Keyboard::Key::C, sf::Keyboard::Scan::C, true, true, true, true};
-        CHECK(event);
         CHECK(event.is<sf::Event::KeyPressed>());
         CHECK(event.getIf<sf::Event::KeyPressed>());
         const auto& keyPressed = *event.getIf<sf::Event::KeyPressed>();
@@ -80,7 +65,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(keyPressed.system);
 
         event = sf::Event::KeyReleased{sf::Keyboard::Key::D, sf::Keyboard::Scan::D, true, true, true, true};
-        CHECK(event);
         CHECK(event.is<sf::Event::KeyReleased>());
         CHECK(event.getIf<sf::Event::KeyReleased>());
         const auto& keyReleased = *event.getIf<sf::Event::KeyReleased>();
@@ -92,7 +76,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(keyReleased.system);
 
         event = sf::Event::MouseWheelScrolled{sf::Mouse::Wheel::Horizontal, 3.14f, {4, 5}};
-        CHECK(event);
         CHECK(event.is<sf::Event::MouseWheelScrolled>());
         CHECK(event.getIf<sf::Event::MouseWheelScrolled>());
         const auto& mouseWheelScrolled = *event.getIf<sf::Event::MouseWheelScrolled>();
@@ -101,7 +84,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(mouseWheelScrolled.position == sf::Vector2i(4, 5));
 
         event = sf::Event::MouseButtonPressed{sf::Mouse::Button::Middle, {6, 7}};
-        CHECK(event);
         CHECK(event.is<sf::Event::MouseButtonPressed>());
         CHECK(event.getIf<sf::Event::MouseButtonPressed>());
         const auto& mouseButtonPressed = *event.getIf<sf::Event::MouseButtonPressed>();
@@ -109,7 +91,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(mouseButtonPressed.position == sf::Vector2i(6, 7));
 
         event = sf::Event::MouseButtonReleased{sf::Mouse::Button::Extra1, {8, 9}};
-        CHECK(event);
         CHECK(event.is<sf::Event::MouseButtonReleased>());
         CHECK(event.getIf<sf::Event::MouseButtonReleased>());
         const auto& mouseButtonReleased = *event.getIf<sf::Event::MouseButtonReleased>();
@@ -117,31 +98,26 @@ TEST_CASE("[Window] sf::Event")
         CHECK(mouseButtonReleased.position == sf::Vector2i(8, 9));
 
         event = sf::Event::MouseMoved{{4, 2}};
-        CHECK(event);
         CHECK(event.is<sf::Event::MouseMoved>());
         CHECK(event.getIf<sf::Event::MouseMoved>());
         const auto& mouseMoved = *event.getIf<sf::Event::MouseMoved>();
         CHECK(mouseMoved.position == sf::Vector2i(4, 2));
 
         event = sf::Event::MouseMovedRaw{{3, 7}};
-        CHECK(event);
         CHECK(event.is<sf::Event::MouseMovedRaw>());
         CHECK(event.getIf<sf::Event::MouseMovedRaw>());
         const auto& mouseMovedRaw = *event.getIf<sf::Event::MouseMovedRaw>();
         CHECK(mouseMovedRaw.delta == sf::Vector2i(3, 7));
 
         event = sf::Event::MouseEntered{};
-        CHECK(event);
         CHECK(event.is<sf::Event::MouseEntered>());
         CHECK(event.getIf<sf::Event::MouseEntered>());
 
         event = sf::Event::MouseLeft{};
-        CHECK(event);
         CHECK(event.is<sf::Event::MouseLeft>());
         CHECK(event.getIf<sf::Event::MouseLeft>());
 
         event = sf::Event::JoystickButtonPressed{100, 200};
-        CHECK(event);
         CHECK(event.is<sf::Event::JoystickButtonPressed>());
         CHECK(event.getIf<sf::Event::JoystickButtonPressed>());
         const auto& joystickButtonPressed = *event.getIf<sf::Event::JoystickButtonPressed>();
@@ -149,7 +125,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(joystickButtonPressed.button == 200);
 
         event = sf::Event::JoystickButtonReleased{300, 400};
-        CHECK(event);
         CHECK(event.is<sf::Event::JoystickButtonReleased>());
         CHECK(event.getIf<sf::Event::JoystickButtonReleased>());
         const auto& joystickButtonReleased = *event.getIf<sf::Event::JoystickButtonReleased>();
@@ -157,7 +132,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(joystickButtonReleased.button == 400);
 
         event = sf::Event::JoystickMoved{300, sf::Joystick::Axis::Z, 1.23f};
-        CHECK(event);
         CHECK(event.is<sf::Event::JoystickMoved>());
         CHECK(event.getIf<sf::Event::JoystickMoved>());
         const auto& joystickMoved = *event.getIf<sf::Event::JoystickMoved>();
@@ -166,21 +140,18 @@ TEST_CASE("[Window] sf::Event")
         CHECK(joystickMoved.position == 1.23f);
 
         event = sf::Event::JoystickConnected{42};
-        CHECK(event);
         CHECK(event.is<sf::Event::JoystickConnected>());
         CHECK(event.getIf<sf::Event::JoystickConnected>());
         const auto& joystickConnected = *event.getIf<sf::Event::JoystickConnected>();
         CHECK(joystickConnected.joystickId == 42);
 
         event = sf::Event::JoystickDisconnected{43};
-        CHECK(event);
         CHECK(event.is<sf::Event::JoystickDisconnected>());
         CHECK(event.getIf<sf::Event::JoystickDisconnected>());
         const auto& joystickDisconnected = *event.getIf<sf::Event::JoystickDisconnected>();
         CHECK(joystickDisconnected.joystickId == 43);
 
         event = sf::Event::TouchBegan{99, {98, 97}};
-        CHECK(event);
         CHECK(event.is<sf::Event::TouchBegan>());
         CHECK(event.getIf<sf::Event::TouchBegan>());
         const auto& touchBegan = *event.getIf<sf::Event::TouchBegan>();
@@ -188,7 +159,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(touchBegan.position == sf::Vector2i(98, 97));
 
         event = sf::Event::TouchMoved{96, {95, 94}};
-        CHECK(event);
         CHECK(event.is<sf::Event::TouchMoved>());
         CHECK(event.getIf<sf::Event::TouchMoved>());
         const auto& touchMoved = *event.getIf<sf::Event::TouchMoved>();
@@ -196,7 +166,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(touchMoved.position == sf::Vector2i(95, 94));
 
         event = sf::Event::TouchEnded{93, {92, 91}};
-        CHECK(event);
         CHECK(event.is<sf::Event::TouchEnded>());
         CHECK(event.getIf<sf::Event::TouchEnded>());
         const auto& touchEnded = *event.getIf<sf::Event::TouchEnded>();
@@ -204,7 +173,6 @@ TEST_CASE("[Window] sf::Event")
         CHECK(touchEnded.position == sf::Vector2i(92, 91));
 
         event = sf::Event::SensorChanged{sf::Sensor::Type::Gravity, {1.2f, 3.4f, 5.6f}};
-        CHECK(event);
         CHECK(event.is<sf::Event::SensorChanged>());
         CHECK(event.getIf<sf::Event::SensorChanged>());
         const auto& sensorChanged = *event.getIf<sf::Event::SensorChanged>();
@@ -215,7 +183,6 @@ TEST_CASE("[Window] sf::Event")
     SECTION("Subtypes")
     {
         // Empty structs
-        STATIC_CHECK(std::is_empty_v<sf::Event::Empty>);
         STATIC_CHECK(std::is_empty_v<sf::Event::Closed>);
         STATIC_CHECK(std::is_empty_v<sf::Event::FocusLost>);
         STATIC_CHECK(std::is_empty_v<sf::Event::FocusGained>);