diff --git a/FL/x.H b/FL/x.H
index 85c6f6c..0ea132f 100644
--- a/FL/x.H
+++ b/FL/x.H
@@ -114,7 +114,7 @@ FL_EXPORT Fl_Region XRectangleRegion(int x, int y, int w, int h); // in fl_rect.
 // With Xlib / X11 fonts, fl_xfont will return the current selected font.
 // With XFT / X11 fonts, fl_xfont will attempt to return the bitmap "core" font most
 // similar to (usually the same as) the current XFT font.
-class Fl_XFont_On_Demand
+class FL_EXPORT Fl_XFont_On_Demand
 {
 public:
   Fl_XFont_On_Demand(XFontStruct* p = NULL) : ptr(p) { }