diff --git a/include/freetype.h b/include/freetype.h
index d89d77c24..ff4e2a88e 100644
--- a/include/freetype.h
+++ b/include/freetype.h
@@ -2370,7 +2370,7 @@
   EXPORT_DEF
   FT_Error  FT_Set_Raster_Mode( FT_Library      library,
                                 FT_Glyph_Format format,
-                                const char*     mode,
+                                unsigned long   mode,
                                 void*           args );
 
 
diff --git a/include/ftimage.h b/include/ftimage.h
index 01f6bad12..584ec4694 100644
--- a/include/ftimage.h
+++ b/include/ftimage.h
@@ -857,14 +857,14 @@
   *
   * <Input>
   *    raster    :: handle to new raster object
-  *    mode      :: an C string naming the mode or property to change
+  *    mode      :: a 4-byte tag used to name the mode or property           
   *    args      :: a pointer to the new mode/property to use
   *
   **************************************************************************/
 
-  typedef int (*FT_Raster_Set_Mode_Func)( FT_Raster    raster,
-                                          const char*  mode,
-                                          void*        args );
+  typedef int (*FT_Raster_Set_Mode_Func)( FT_Raster      raster,
+                                          unsigned long  mode,
+                                          void*          args );
 
  /**************************************************************************
   *
diff --git a/src/base/ftobjs.c b/src/base/ftobjs.c
index 08e898346..121ab1187 100644
--- a/src/base/ftobjs.c
+++ b/src/base/ftobjs.c
@@ -594,7 +594,7 @@
   EXPORT_FUNC
   FT_Error  FT_Set_Raster_Mode( FT_Library      library,
                                 FT_Glyph_Format format,
-                                const char*     mode,
+                                unsigned long   mode,
                                 void*           args )
   {
     FT_Raster_Funcs  funcs;