REVIEWED: GetWindowHandle(), to be consistent between backends, fix #5885

Returns the underlying window handle for platforms with some windowing system.

src/platforms/rcore_android.c

@@ -473,8 +473,7 @@ void SetWindowFocused(void)
 // Get native window handle
 void *GetWindowHandle(void)
 {
-    TRACELOG(LOG_WARNING, "GetWindowHandle() not implemented on target platform");
-    return NULL;
+    return (void *)platform.app->window; // Type: ANativeWindow*
 }
 
 // Get number of monitors

src/platforms/rcore_desktop_glfw.c

@@ -115,7 +115,7 @@ typedef struct {
     // Local storage for the window handle returned by glfwGetX11Window
     // This is needed as X11 handles are integers and may not fit inside a pointer depending on platform
     // Storing the handle locally and returning a pointer in GetWindowHandle allows the code to work regardless of pointer width
-    XID windowHandleX11;
+    Window windowHandleX11;             // Underlying type: unsigned long (XID, Window)
 #endif
 } PlatformData;
 
@@ -764,9 +764,10 @@ void SetWindowFocused(void)
 // Get native window handle
 void *GetWindowHandle(void)
 {
+    void *handle = NULL;
+
 #if defined(_WIN32)
-    // NOTE: Returned handle is: void *HWND (windows.h)
-    return glfwGetWin32Window(platform.handle);
+    handle = glfwGetWin32Window(platform.handle); // Type: HWND
 #endif
 #if defined(__linux__)
     #if defined(_GLFW_WAYLAND)
@@ -774,28 +775,27 @@ void *GetWindowHandle(void)
             int platformID = glfwGetPlatform();
             if (platformID == GLFW_PLATFORM_WAYLAND)
             {
-                return glfwGetWaylandWindow(platform.handle);
+                handle = (void *)glfwGetWaylandWindow(platform.handle); // Type: struct wl_surface*
             }
             else
             {
-                platform.windowHandleX11 = glfwGetX11Window(platform.handle);
-                return &platform.windowHandleX11;
+                platform.windowHandleX11 = glfwGetX11Window(platform.handle); // Type: Window (unsigned long)
+                handle = &platform.windowHandleX11;
             }
         #else
-            return glfwGetWaylandWindow(platform.handle);
+            handle = (void *)glfwGetWaylandWindow(platform.handle);
         #endif
     #elif defined(_GLFW_X11)
-        // Store the window handle localy and return a pointer to the variable instead
+        // Store the window handle locally and return a pointer to the variable instead
         platform.windowHandleX11 = glfwGetX11Window(platform.handle);
-        return &platform.windowHandleX11;
+        handle = &platform.windowHandleX11;
     #endif
 #endif
 #if defined(__APPLE__)
-    // NOTE: Returned handle is: (objc_object *)
-    return (void *)glfwGetCocoaWindow(platform.handle);
+    handle = (void *)glfwGetCocoaWindow(platform.handle); // Type: NSWindow*
 #endif
 
-    return NULL;
+    return handle;
 }
 
 // Get number of monitors

src/platforms/rcore_desktop_rgfw.c

@@ -184,6 +184,9 @@ typedef struct {
     i32 surfaceWidth;
     i32 surfaceHeight;
 #endif
+#if defined(__linux__) && defined(RGFW_X11)
+    Window windowHandleX11;             // Underlying type: unsigned long
+#endif
 } PlatformData;
 
 //----------------------------------------------------------------------------------
@@ -851,15 +854,25 @@ void SetWindowFocused(void)
 // Get native window handle
 void *GetWindowHandle(void)
 {
-    if (platform.window == NULL) return NULL;
+    void *handle = NULL;
 
-#if defined(RGFW_WASM)
-    return (void *)&platform.window->src.ctx;
-#elif defined(RGFW_WAYLAND)
-    return (void *)platform.window->src.surface;
-#else
-    return (void *)platform.window->src.window;
+    if (platform.window != NULL)
+    {
+#if defined(_WIN32)
+        handle = (void *)platform.window->src.window; // Type: HWND
+#elif defined(__linux__)
+    #if defined(RGFW_X11)
+        platform.windowHandleX11 = platform.window->src.window; // Type: Window (unsigned long)
+        handle = &platform.window->src.window; 
+    #elif defined(RGFW_WAYLAND)
+        handle = (void *)platform.window->src.surface; // Type: struct wl_surface*
+    #endif
+#elif defined(__APPLE__)
+        handle = (void *)platform.window->src.window; // Type: id, NSWindow*
 #endif
+    }
+
+    return handle;
 }
 
 // Get number of monitors

src/platforms/rcore_desktop_sdl.c

@@ -56,6 +56,7 @@
     #include "SDL3/SDL.h"
 #elif defined(USING_SDL2_PROJECT)
     #include "SDL2/SDL.h"
+    #include "SDL2/SDL_syswm.h"     // Required to get window handlers 
 #else
     #include "SDL.h"
 #endif
@@ -101,6 +102,13 @@ typedef struct {
     SDL_GameController *gamepad[MAX_GAMEPADS];
     SDL_JoystickID gamepadId[MAX_GAMEPADS]; // Joystick instance ids, they do not start from 0
     SDL_Cursor *cursor;
+
+#if defined(__linux__)
+    // Local storage for the window handle (X11)
+    // NOTE: On SDL is not possible to know windowing backend at compile time, so,
+    // just in case, avoiding X11 specific types here
+    unsigned long windowHandleX11;          // Underlying type for: XID, Window
+#endif
 } PlatformData;
 
 //----------------------------------------------------------------------------------
@@ -920,9 +928,60 @@ void SetWindowFocused(void)
 }
 
 // Get native window handle
+// NOTE: Handle type depends on OS and windowing system
 void *GetWindowHandle(void)
 {
-    return (void *)platform.window;
+    void *handle = NULL;
+
+#if defined(USING_SDL3_PROJECT)
+    // REF: https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_video.h#L1590
+    SDL_PropertiesID props = SDL_GetWindowProperties(platform.window);
+    #if defined(_WIN32)
+    handle = (void *)SDL_GetPointerProperty(props, SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL); // Type: HWND
+    #elif defined(__linux__)
+    unsigned long windowId = (unsigned long)SDL_GetNumberProperty(props, SDL_PROP_WINDOW_X11_WINDOW_NUMBER, 0); // Type: unsigned long (XID, Window)
+    if (windowId != 0)
+    {
+        // X11 window ID
+        platform.windowHandleX11 = windowId;
+        handle = &platform.windowHandleX11;
+    }
+    else
+    {
+        // Wayland, get display surface pointer
+        // NOTE: Alternative SDL_PROP_WINDOW_WAYLAND_DISPLAY_POINTER
+        handle = (void *)SDL_GetPointerProperty(props, SDL_PROP_WINDOW_WAYLAND_SURFACE_POINTER, NULL); // Type: struct wl_surface*
+    }
+    #elif defined(__APPLE__)
+    handle = (void *)SDL_GetPointerProperty(props, SDL_PROP_WINDOW_COCOA_WINDOW_POINTER, NULL); // Type: NSWindow*
+    #endif
+#elif defined(USING_SDL2_PROJECT)
+    SDL_SysWMinfo wmInfo = { 0 };
+    SDL_VERSION(&wmInfo.version);
+    if (SDL_GetWindowWMInfo(platform.window, &wmInfo))
+    {
+    #if defined(_WIN32)
+        handle = (void *)wmInfo.info.win.window; // Type: HWND
+    #elif defined(__linux__)
+        if (wmInfo.subsystem == SDL_SYSWM_X11)
+        {
+            // X11, get window ID (unsigned long)
+            platform.windowHandleX11 = (unsigned long)wmInfo.info.x11.window;
+            handle = &platform.windowHandleX11;
+        }
+        else if (wmInfo.subsystem == SDL_SYSWM_WAYLAND)
+        {
+            // Wayland, get display surface pointer
+            // NOTE: Alternative: wmInfo.info.wl.display
+            handle = (void *)wmInfo.info.wl.surface; // Type: struct wl_surface*
+        }
+    #elif defined(__APPLE__)
+        handle = (void *)wmInfo.info.cocoa.window; // Type: NSWindow*
+    #endif
+    }
+#endif
+
+    return handle;
 }
 
 // Get number of monitors

src/platforms/rcore_desktop_win32.c

@@ -1023,7 +1023,7 @@ void SetWindowFocused(void)
 // Get native window handle
 void *GetWindowHandle(void)
 {
-    return platform.hwnd;
+    return (void *)platform.hwnd;
 }
 
 int GetMonitorCount(void)