diff --git a/.gitignore b/.gitignore
index 9d2d504b..48b251d9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -102,3 +102,7 @@ tests/triangle-vulkan
 tests/window
 tests/windows
 
+# IDE caches
+.cache/
+.idea/
+.vscode/
\ No newline at end of file
diff --git a/src/cocoa_init.m b/src/cocoa_init.m
index b3831df1..d925b4bd 100644
--- a/src/cocoa_init.m
+++ b/src/cocoa_init.m
@@ -525,6 +525,7 @@ GLFWbool _glfwConnectCocoa(int platformID, _GLFWplatform* platform)
         _glfwGetGammaRampCocoa,
         _glfwSetGammaRampCocoa,
         _glfwCreateWindowCocoa,
+        _glfwAttachWindowCocoa,
         _glfwDestroyWindowCocoa,
         _glfwSetWindowTitleCocoa,
         _glfwSetWindowIconCocoa,
@@ -694,4 +695,3 @@ void _glfwTerminateCocoa(void)
 }
 
 #endif // _GLFW_COCOA
-
diff --git a/src/cocoa_platform.h b/src/cocoa_platform.h
index 9f7d191d..76d79226 100644
--- a/src/cocoa_platform.h
+++ b/src/cocoa_platform.h
@@ -215,6 +215,7 @@ int _glfwInitCocoa(void);
 void _glfwTerminateCocoa(void);
 
 GLFWbool _glfwCreateWindowCocoa(_GLFWwindow* window, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
+GLFWbool _glfwAttachWindowCocoa(_GLFWwindow* window, intptr_t native, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
 void _glfwDestroyWindowCocoa(_GLFWwindow* window);
 void _glfwSetWindowTitleCocoa(_GLFWwindow* window, const char* title);
 void _glfwSetWindowIconCocoa(_GLFWwindow* window, int count, const GLFWimage* images);
@@ -299,4 +300,3 @@ GLFWbool _glfwCreateContextNSGL(_GLFWwindow* window,
                                 const _GLFWctxconfig* ctxconfig,
                                 const _GLFWfbconfig* fbconfig);
 void _glfwDestroyContextNSGL(_GLFWwindow* window);
-
diff --git a/src/cocoa_window.m b/src/cocoa_window.m
index 9d794940..a83e6149 100644
--- a/src/cocoa_window.m
+++ b/src/cocoa_window.m
@@ -988,6 +988,15 @@ GLFWbool _glfwCreateWindowCocoa(_GLFWwindow* window,
     } // autoreleasepool
 }
 
+GLFWbool _glfwAttachWindowCocoa(_GLFWwindow* window,
+                                intptr_t native,
+                                const _GLFWwndconfig* wndconfig,
+                                const _GLFWctxconfig* ctxconfig,
+                                const _GLFWfbconfig* fbconfig) {
+    _glfwInputError(GLFW_PLATFORM_ERROR, "Cocoa window attachment is not implemented");
+    return GLFW_FALSE;
+}
+
 void _glfwDestroyWindowCocoa(_GLFWwindow* window)
 {
     @autoreleasepool {
@@ -2055,4 +2064,3 @@ GLFWAPI id glfwGetCocoaWindow(GLFWwindow* handle)
 }
 
 #endif // _GLFW_COCOA
-
diff --git a/src/internal.h b/src/internal.h
index fe0369aa..05c1f5cc 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -532,6 +532,7 @@ struct _GLFWwindow
     GLFWbool            focusOnShow;
     GLFWbool            mousePassthrough;
     GLFWbool            shouldClose;
+    GLFWbool            external;
     void*               userPointer;
     GLFWbool            doublebuffer;
     GLFWvidmode         videoMode;
@@ -706,6 +707,7 @@ struct _GLFWplatform
     void (*setGammaRamp)(_GLFWmonitor*,const GLFWgammaramp*);
     // window
     GLFWbool (*createWindow)(_GLFWwindow*,const _GLFWwndconfig*,const _GLFWctxconfig*,const _GLFWfbconfig*);
+    GLFWbool (*attachWindow)(_GLFWwindow*, intptr_t, const _GLFWwndconfig*,const _GLFWctxconfig*,const _GLFWfbconfig*);
     void (*destroyWindow)(_GLFWwindow*);
     void (*setWindowTitle)(_GLFWwindow*,const char*);
     void (*setWindowIcon)(_GLFWwindow*,int,const GLFWimage*);
diff --git a/src/null_init.c b/src/null_init.c
index 34ddc04a..1ff95e37 100644
--- a/src/null_init.c
+++ b/src/null_init.c
@@ -69,6 +69,7 @@ GLFWbool _glfwConnectNull(int platformID, _GLFWplatform* platform)
         _glfwGetGammaRampNull,
         _glfwSetGammaRampNull,
         _glfwCreateWindowNull,
+        _glfwAttachWindowNull,
         _glfwDestroyWindowNull,
         _glfwSetWindowTitleNull,
         _glfwSetWindowIconNull,
@@ -261,4 +262,3 @@ void _glfwTerminateNull(void)
     _glfwTerminateOSMesa();
     _glfwTerminateEGL();
 }
-
diff --git a/src/null_platform.h b/src/null_platform.h
index fb9374b4..64209880 100644
--- a/src/null_platform.h
+++ b/src/null_platform.h
@@ -210,6 +210,7 @@ GLFWbool _glfwGetGammaRampNull(_GLFWmonitor* monitor, GLFWgammaramp* ramp);
 void _glfwSetGammaRampNull(_GLFWmonitor* monitor, const GLFWgammaramp* ramp);
 
 GLFWbool _glfwCreateWindowNull(_GLFWwindow* window, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
+GLFWbool _glfwAttachWindowNull(_GLFWwindow* window, intptr_t native, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
 void _glfwDestroyWindowNull(_GLFWwindow* window);
 void _glfwSetWindowTitleNull(_GLFWwindow* window, const char* title);
 void _glfwSetWindowIconNull(_GLFWwindow* window, int count, const GLFWimage* images);
@@ -269,4 +270,3 @@ GLFWbool _glfwGetPhysicalDevicePresentationSupportNull(VkInstance instance, VkPh
 VkResult _glfwCreateWindowSurfaceNull(VkInstance instance, _GLFWwindow* window, const VkAllocationCallbacks* allocator, VkSurfaceKHR* surface);
 
 void _glfwPollMonitorsNull(void);
-
diff --git a/src/null_window.c b/src/null_window.c
index c2aafbad..0bd6b9f5 100644
--- a/src/null_window.c
+++ b/src/null_window.c
@@ -104,6 +104,39 @@ static int createNativeWindow(_GLFWwindow* window,
 
     return GLFW_TRUE;
 }
+static int attachNativeWindow(_GLFWwindow* window,
+                              intptr_t native,
+                              const _GLFWwndconfig* wndconfig,
+                              const _GLFWfbconfig* fbconfig)
+{
+    if (window->monitor)
+        fitToMonitor(window);
+    else
+    {
+        if (wndconfig->xpos == GLFW_ANY_POSITION && wndconfig->ypos == GLFW_ANY_POSITION)
+        {
+            window->null.xpos = 17;
+            window->null.ypos = 17;
+        }
+        else
+        {
+            window->null.xpos = wndconfig->xpos;
+            window->null.ypos = wndconfig->ypos;
+        }
+
+        window->null.width = wndconfig->width;
+        window->null.height = wndconfig->height;
+    }
+
+    window->null.visible = wndconfig->visible;
+    window->null.decorated = wndconfig->decorated;
+    window->null.maximized = wndconfig->maximized;
+    window->null.floating = wndconfig->floating;
+    window->null.transparent = fbconfig->transparent;
+    window->null.opacity = 1.f;
+
+    return GLFW_TRUE;
+}
 
 
 //////////////////////////////////////////////////////////////////////////
@@ -164,6 +197,61 @@ GLFWbool _glfwCreateWindowNull(_GLFWwindow* window,
 
     return GLFW_TRUE;
 }
+GLFWbool _glfwAttachWindowNull(_GLFWwindow* window,
+                               intptr_t native,
+                               const _GLFWwndconfig* wndconfig,
+                               const _GLFWctxconfig* ctxconfig,
+                               const _GLFWfbconfig* fbconfig)
+{
+    if (!attachNativeWindow(window, native, wndconfig, fbconfig))
+        return GLFW_FALSE;
+
+    if (ctxconfig->client != GLFW_NO_API)
+    {
+        if (ctxconfig->source == GLFW_NATIVE_CONTEXT_API ||
+            ctxconfig->source == GLFW_OSMESA_CONTEXT_API)
+        {
+            if (!_glfwInitOSMesa())
+                return GLFW_FALSE;
+            if (!_glfwCreateContextOSMesa(window, ctxconfig, fbconfig))
+                return GLFW_FALSE;
+        }
+        else if (ctxconfig->source == GLFW_EGL_CONTEXT_API)
+        {
+            if (!_glfwInitEGL())
+                return GLFW_FALSE;
+            if (!_glfwCreateContextEGL(window, ctxconfig, fbconfig))
+                return GLFW_FALSE;
+        }
+
+        if (!_glfwRefreshContextAttribs(window, ctxconfig))
+            return GLFW_FALSE;
+    }
+
+    if (wndconfig->mousePassthrough)
+        _glfwSetWindowMousePassthroughNull(window, GLFW_TRUE);
+
+    if (window->monitor)
+    {
+        _glfwShowWindowNull(window);
+        _glfwFocusWindowNull(window);
+        acquireMonitor(window);
+
+        if (wndconfig->centerCursor)
+            _glfwCenterCursorInContentArea(window);
+    }
+    else
+    {
+        if (wndconfig->visible)
+        {
+            _glfwShowWindowNull(window);
+            if (wndconfig->focused)
+                _glfwFocusWindowNull(window);
+        }
+    }
+
+    return GLFW_TRUE;
+}
 
 void _glfwDestroyWindowNull(_GLFWwindow* window)
 {
@@ -715,4 +803,3 @@ VkResult _glfwCreateWindowSurfaceNull(VkInstance instance,
     // This seems like the most appropriate error to return here
     return VK_ERROR_EXTENSION_NOT_PRESENT;
 }
-
diff --git a/src/win32_init.c b/src/win32_init.c
index 739c9c33..baec5aea 100644
--- a/src/win32_init.c
+++ b/src/win32_init.c
@@ -672,6 +672,7 @@ GLFWbool _glfwConnectWin32(int platformID, _GLFWplatform* platform)
         _glfwGetGammaRampWin32,
         _glfwSetGammaRampWin32,
         _glfwCreateWindowWin32,
+        _glfwAttachWindowWin32,
         _glfwDestroyWindowWin32,
         _glfwSetWindowTitleWin32,
         _glfwSetWindowIconWin32,
@@ -777,4 +778,3 @@ void _glfwTerminateWin32(void)
 }
 
 #endif // _GLFW_WIN32
-
diff --git a/src/win32_platform.h b/src/win32_platform.h
index 1db31584..c7add55b 100644
--- a/src/win32_platform.h
+++ b/src/win32_platform.h
@@ -544,6 +544,7 @@ void _glfwRestoreVideoModeWin32(_GLFWmonitor* monitor);
 void _glfwGetHMONITORContentScaleWin32(HMONITOR handle, float* xscale, float* yscale);
 
 GLFWbool _glfwCreateWindowWin32(_GLFWwindow* window, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
+GLFWbool _glfwAttachWindowWin32(_GLFWwindow* window, intptr_t native, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
 void _glfwDestroyWindowWin32(_GLFWwindow* window);
 void _glfwSetWindowTitleWin32(_GLFWwindow* window, const char* title);
 void _glfwSetWindowIconWin32(_GLFWwindow* window, int count, const GLFWimage* images);
@@ -625,4 +626,3 @@ void _glfwTerminateWGL(void);
 GLFWbool _glfwCreateContextWGL(_GLFWwindow* window,
                                const _GLFWctxconfig* ctxconfig,
                                const _GLFWfbconfig* fbconfig);
-
diff --git a/src/win32_window.c b/src/win32_window.c
index db3bed6e..257e956d 100644
--- a/src/win32_window.c
+++ b/src/win32_window.c
@@ -1524,6 +1524,11 @@ GLFWbool _glfwCreateWindowWin32(_GLFWwindow* window,
     return GLFW_TRUE;
 }
 
+GLFWbool _glfwAttachWindowWin32(_GLFWwindow* window, intptr_t native, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig) {
+    _glfwInputError(GLFW_PLATFORM_ERROR, "Win32 window attachment is not implemented");
+    return GLFW_FALSE;
+}
+
 void _glfwDestroyWindowWin32(_GLFWwindow* window)
 {
     if (window->monitor)
@@ -2542,4 +2547,3 @@ GLFWAPI HWND glfwGetWin32Window(GLFWwindow* handle)
 }
 
 #endif // _GLFW_WIN32
-
diff --git a/src/window.c b/src/window.c
index 1117df2f..ad3f55e3 100644
--- a/src/window.c
+++ b/src/window.c
@@ -252,8 +252,55 @@ GLFWAPI GLFWwindow* glfwCreateWindow(int width, int height,
     return (GLFWwindow*) window;
 }
 
-void glfwDefaultWindowHints(void)
-{
+GLFWAPI GLFWwindow* glfwAttachWindow(intptr_t nativeWindow, GLFWwindow* share) {
+  _GLFWfbconfig fbconfig;
+  _GLFWctxconfig ctxconfig;
+  _GLFWwndconfig wndconfig;
+  _GLFWwindow* window;
+
+  _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
+
+  fbconfig  = _glfw.hints.framebuffer;
+  ctxconfig = _glfw.hints.context;
+  wndconfig = _glfw.hints.window;
+
+  ctxconfig.share = (_GLFWwindow*) share;
+  if (ctxconfig.share)
+  {
+    if (ctxconfig.client == GLFW_NO_API ||
+      ctxconfig.share->context.client == GLFW_NO_API)
+    {
+      _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+      return NULL;
+    }
+  }
+
+  if (!_glfwIsValidContextConfig(&ctxconfig))
+    return NULL;
+
+  window = calloc(1, sizeof(_GLFWwindow));
+  window->next = _glfw.windowListHead;
+  _glfw.windowListHead = window;
+
+  window->autoIconify = wndconfig.autoIconify;
+  window->cursorMode  = GLFW_CURSOR_NORMAL;
+  window->external    = GLFW_TRUE;
+
+  window->minwidth    = GLFW_DONT_CARE;
+  window->minheight   = GLFW_DONT_CARE;
+  window->maxwidth    = GLFW_DONT_CARE;
+  window->maxheight   = GLFW_DONT_CARE;
+  window->numer       = GLFW_DONT_CARE;
+  window->denom       = GLFW_DONT_CARE;
+
+  if (!_glfw.platform.attachWindow(window, nativeWindow, &wndconfig, &ctxconfig, &fbconfig))
+    return NULL;
+
+  return (GLFWwindow*) window;
+}
+
+void glfwDefaultWindowHints(void) {
+
     _GLFW_REQUIRE_INIT();
 
     // The default is OpenGL with minimum version 1.0
@@ -1150,4 +1197,3 @@ GLFWAPI void glfwPostEmptyEvent(void)
     _GLFW_REQUIRE_INIT();
     _glfw.platform.postEmptyEvent();
 }
-
diff --git a/src/wl_init.c b/src/wl_init.c
index a4692b52..ffecd6da 100644
--- a/src/wl_init.c
+++ b/src/wl_init.c
@@ -443,6 +443,7 @@ GLFWbool _glfwConnectWayland(int platformID, _GLFWplatform* platform)
         _glfwGetGammaRampWayland,
         _glfwSetGammaRampWayland,
         _glfwCreateWindowWayland,
+        _glfwAttachWindowWayland,
         _glfwDestroyWindowWayland,
         _glfwSetWindowTitleWayland,
         _glfwSetWindowIconWayland,
@@ -946,4 +947,3 @@ void _glfwTerminateWayland(void)
 }
 
 #endif // _GLFW_WAYLAND
-
diff --git a/src/wl_platform.h b/src/wl_platform.h
index d00e28fe..0e539629 100644
--- a/src/wl_platform.h
+++ b/src/wl_platform.h
@@ -610,6 +610,7 @@ int _glfwInitWayland(void);
 void _glfwTerminateWayland(void);
 
 GLFWbool _glfwCreateWindowWayland(_GLFWwindow* window, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
+GLFWbool _glfwAttachWindowWayland(_GLFWwindow* window, intptr_t native, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
 void _glfwDestroyWindowWayland(_GLFWwindow* window);
 void _glfwSetWindowTitleWayland(_GLFWwindow* window, const char* title);
 void _glfwSetWindowIconWayland(_GLFWwindow* window, int count, const GLFWimage* images);
diff --git a/src/wl_window.c b/src/wl_window.c
index 76c6a763..4bf86da1 100644
--- a/src/wl_window.c
+++ b/src/wl_window.c
@@ -967,6 +967,38 @@ static GLFWbool createNativeSurface(_GLFWwindow* window,
     return GLFW_TRUE;
 }
 
+static GLFWbool attachNativeSurface(_GLFWwindow* window,
+                                    intptr_t native,
+                                    const _GLFWwndconfig* wndconfig,
+                                    const _GLFWfbconfig* fbconfig) {
+    if (!native)
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR, "Wayland: supplied wl_surface is null");
+        return GLFW_FALSE;
+    }
+    window->wl.surface = (struct wl_surface*) native;
+    
+    wl_proxy_set_tag((struct wl_proxy*) window->wl.surface, &_glfw.wl.tag);
+    wl_surface_add_listener(window->wl.surface,
+                            &surfaceListener,
+                            window);
+    
+    window->wl.width = wndconfig->width;
+    window->wl.height = wndconfig->height;
+    window->wl.contentScale = 1;
+    window->wl.title = _glfw_strdup(wndconfig->title);
+    window->wl.appId = _glfw_strdup(wndconfig->wl.appId);
+    
+    
+    window->wl.maximized = wndconfig->maximized;
+
+    window->wl.transparent = fbconfig->transparent;
+    if (!window->wl.transparent)
+        setContentAreaOpaque(window);
+    
+    return GLFW_TRUE;
+}
+
 static void setCursorImage(_GLFWwindow* window,
                            _GLFWcursorWayland* cursorWayland)
 {
@@ -2046,7 +2078,8 @@ GLFWbool _glfwCreateWindowWayland(_GLFWwindow* window,
     if (wndconfig->mousePassthrough)
         _glfwSetWindowMousePassthroughWayland(window, GLFW_TRUE);
 
-    if (window->monitor || wndconfig->visible)
+    // don't
+    if (!window->external && (window->monitor || wndconfig->visible))
     {
         if (!createShellObjects(window))
             return GLFW_FALSE;
@@ -2055,6 +2088,52 @@ GLFWbool _glfwCreateWindowWayland(_GLFWwindow* window,
     return GLFW_TRUE;
 }
 
+GLFWbool _glfwAttachWindowWayland(_GLFWwindow* window,
+                                  intptr_t native,
+                                  const _GLFWwndconfig* wndconfig,
+                                  const _GLFWctxconfig* ctxconfig,
+                                  const _GLFWfbconfig* fbconfig) {
+
+    if (!attachNativeSurface(window, native, wndconfig, fbconfig))
+        return GLFW_FALSE;
+    if (ctxconfig->client != GLFW_NO_API)
+    {
+        if (ctxconfig->source == GLFW_EGL_CONTEXT_API ||
+            ctxconfig->source == GLFW_NATIVE_CONTEXT_API)
+        {
+            window->wl.egl.window = wl_egl_window_create(window->wl.surface,
+                                                         wndconfig->width,
+                                                         wndconfig->height);
+            if (!window->wl.egl.window)
+            {
+                _glfwInputError(GLFW_PLATFORM_ERROR,
+                                "Wayland: Failed to create EGL window");
+                return GLFW_FALSE;
+            }
+
+            if (!_glfwInitEGL())
+                return GLFW_FALSE;
+            if (!_glfwCreateContextEGL(window, ctxconfig, fbconfig))
+                return GLFW_FALSE;
+        }
+        else if (ctxconfig->source == GLFW_OSMESA_CONTEXT_API)
+        {
+            if (!_glfwInitOSMesa())
+                return GLFW_FALSE;
+            if (!_glfwCreateContextOSMesa(window, ctxconfig, fbconfig))
+                return GLFW_FALSE;
+        }
+
+        if (!_glfwRefreshContextAttribs(window, ctxconfig))
+            return GLFW_FALSE;
+    }
+
+    if (wndconfig->mousePassthrough)
+        _glfwSetWindowMousePassthroughWayland(window, GLFW_TRUE);
+
+    return GLFW_TRUE;
+}
+
 void _glfwDestroyWindowWayland(_GLFWwindow* window)
 {
     if (window == _glfw.wl.pointerFocus)
@@ -2324,7 +2403,7 @@ void _glfwMaximizeWindowWayland(_GLFWwindow* window)
 
 void _glfwShowWindowWayland(_GLFWwindow* window)
 {
-    if (!window->wl.libdecor.frame && !window->wl.xdg.toplevel)
+    if (!window->external && (!window->wl.libdecor.frame && !window->wl.xdg.toplevel))
     {
         // NOTE: The XDG surface and role are created here so command-line applications
         //       with off-screen windows do not appear in for example the Unity dock
@@ -3173,4 +3252,3 @@ GLFWAPI struct wl_surface* glfwGetWaylandWindow(GLFWwindow* handle)
 }
 
 #endif // _GLFW_WAYLAND
-
diff --git a/src/x11_init.c b/src/x11_init.c
index c90b593c..8d527708 100644
--- a/src/x11_init.c
+++ b/src/x11_init.c
@@ -1204,6 +1204,7 @@ GLFWbool _glfwConnectX11(int platformID, _GLFWplatform* platform)
         _glfwGetGammaRampX11,
         _glfwSetGammaRampX11,
         _glfwCreateWindowX11,
+        _glfwAttachWindowX11,
         _glfwDestroyWindowX11,
         _glfwSetWindowTitleX11,
         _glfwSetWindowIconX11,
@@ -1653,4 +1654,3 @@ void _glfwTerminateX11(void)
 }
 
 #endif // _GLFW_X11
-
diff --git a/src/x11_monitor.c b/src/x11_monitor.c
index ae626643..270eb4a7 100644
--- a/src/x11_monitor.c
+++ b/src/x11_monitor.c
@@ -615,4 +615,3 @@ GLFWAPI RROutput glfwGetX11Monitor(GLFWmonitor* handle)
 }
 
 #endif // _GLFW_X11
-
diff --git a/src/x11_platform.h b/src/x11_platform.h
index cdea3957..fc7cdae9 100644
--- a/src/x11_platform.h
+++ b/src/x11_platform.h
@@ -902,6 +902,7 @@ int _glfwInitX11(void);
 void _glfwTerminateX11(void);
 
 GLFWbool _glfwCreateWindowX11(_GLFWwindow* window, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
+GLFWbool _glfwAttachWindowX11(_GLFWwindow* window, intptr_t native, const _GLFWwndconfig* wndconfig, const _GLFWctxconfig* ctxconfig, const _GLFWfbconfig* fbconfig);
 void _glfwDestroyWindowX11(_GLFWwindow* window);
 void _glfwSetWindowTitleX11(_GLFWwindow* window, const char* title);
 void _glfwSetWindowIconX11(_GLFWwindow* window, int count, const GLFWimage* images);
@@ -1001,4 +1002,3 @@ GLFWbool _glfwChooseVisualGLX(const _GLFWwndconfig* wndconfig,
                               const _GLFWctxconfig* ctxconfig,
                               const _GLFWfbconfig* fbconfig,
                               Visual** visual, int* depth);
-
diff --git a/src/x11_window.c b/src/x11_window.c
index 3c76d3a9..dd7331c0 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -2042,6 +2042,15 @@ GLFWbool _glfwCreateWindowX11(_GLFWwindow* window,
     return GLFW_TRUE;
 }
 
+GLFWbool _glfwAttachWindowX11(_GLFWwindow* window,
+                              intptr_t native,
+                              const _GLFWwndconfig* wndconfig,
+                              const _GLFWctxconfig* ctxconfig,
+                              const _GLFWfbconfig* fbconfig) {
+    _glfwInputError(GLFW_PLATFORM_ERROR, "X11 window attachment is not implemented");
+    return GLFW_FALSE;
+}
+
 void _glfwDestroyWindowX11(_GLFWwindow* window)
 {
     if (_glfw.x11.disabledCursorWindow == window)
@@ -3350,4 +3359,3 @@ GLFWAPI const char* glfwGetX11SelectionString(void)
 }
 
 #endif // _GLFW_X11
-