diff --git a/FL/Fl_Window_Driver.H b/FL/Fl_Window_Driver.H
index 41c2e75a9..dac150186 100644
--- a/FL/Fl_Window_Driver.H
+++ b/FL/Fl_Window_Driver.H
@@ -181,7 +181,7 @@ public:
 #endif
   virtual int scroll(int src_x, int src_y, int src_w, int src_h, int dest_x, int dest_y,
                      void (*draw_area)(void*, int,int,int,int), void* data) { return 0; }
-  static Fl_Window_Driver* driver(const Fl_Window *win) {return win->pWindowDriver;}
+  static inline Fl_Window_Driver* driver(const Fl_Window *win) {return win->pWindowDriver;}
 };
 
 #endif // FL_WINDOW_DRIVER_H