1 files changed, 26 insertions, 0 deletions
diff --git a/src/Fl_Window_Driver.cxx b/src/Fl_Window_Driver.cxx
index 23c66be7f..a9faa3211 100644
--- a/src/Fl_Window_Driver.cxx
+++ b/src/Fl_Window_Driver.cxx
@@ -258,6 +258,32 @@ void Fl_Window_Driver::menu_window_area(int &X, int &Y, int &W, int &H, int nscr
   scr_driver->screen_work_area(X, Y, W, H, nscreen);
 }
 
+/** Returns  the platform-specific reference of the given window, or NULL if that window isn't shown.
+ \version 1.4.0 */
+fl_uintptr_t Fl_Window_Driver::xid(const Fl_Window *win) {
+  Fl_X *flx = win->i;
+  return flx ? flx->xid : 0;
+}
+
+/** Returns a pointer to the Fl_Window corresponding to the platform-specific reference \p xid of a shown window.
+ \version 1.4.0 */
+Fl_Window *Fl_Window_Driver::find(fl_uintptr_t xid) {
+  Fl_X *window;
+  for (Fl_X **pp = &Fl_X::first; (window = *pp); pp = &window->next) {
+    if (window->xid == xid) {
+      if (window != Fl_X::first && !Fl::modal()) {
+        // make this window be first to speed up searches
+        // this is not done if modal is true to avoid messing up modal stack
+        *pp = window->next;
+        window->next = Fl_X::first;
+        Fl_X::first = window;
+      }
+      return window->w;
+    }
+  }
+  return 0;
+}
+
 /**
  \}
  \endcond