diff --git a/FL/Fl.H b/FL/Fl.H
index ccecb3adb..720899b91 100644
--- a/FL/Fl.H
+++ b/FL/Fl.H
@@ -22,8 +22,9 @@
 #  define Fl_H
 
 #include <FL/Fl_Export.H>
-
 #include <FL/platform_types.h> // for FL_SOCKET
+#include <FL/fl_casts.H>       // experimental
+
 #ifdef FLTK_HAVE_CAIRO
 # include <FL/Fl_Cairo.H>
 #endif
diff --git a/FL/fl_casts.H b/FL/fl_casts.H
new file mode 100644
index 000000000..b4968c055
--- /dev/null
+++ b/FL/fl_casts.H
@@ -0,0 +1,23 @@
+// experimental inline cast functions for the Fast Light Toolkit (FLTK)
+
+#include <FL/platform_types.h>
+
+inline char fl_char(void *v) { return (char)(fl_intptr_t)v; }
+inline int  fl_int(void *v)  { return (int)(fl_intptr_t)v; }
+inline long fl_long(void *v) { return (long)(fl_intptr_t)v; }
+
+inline unsigned char fl_uchar(void *v) { return (unsigned char)(fl_uintptr_t)v; }
+inline unsigned int  fl_uint(void *v)  { return (unsigned int)(fl_uintptr_t)v; }
+inline unsigned long fl_ulong(void *v) { return (unsigned long)(fl_uintptr_t)v; }
+
+#if 0 /* not necessary */
+
+inline char fl_char(size_t v) { return (char)v; }
+inline int  fl_int(size_t v)  { return (int)v; }
+inline long fl_long(size_t v) { return (long)v; }
+
+inline unsigned char fl_uchar(size_t v) { return (unsigned char)v; }
+inline unsigned int  fl_uint(size_t v)  { return (unsigned int)v; }
+inline unsigned long fl_ulong(size_t v) { return (unsigned long)v; }
+
+#endif /* not necessary */