@@ -4,7 +4,11 @@
 require 'ffi-internal.so'
 
 class Win32API
-  SUFFIXES = $KCODE == 'UTF8' ? [ '', 'W', 'A' ] : [ '', 'A', 'W' ]
+  if RUBY_VERSION =~ /1\.9/
+    SUFFIXES = Encoding.default_internal == Encoding::UTF_8 ? [ '', 'W', 'A' ] : [ '', 'A', 'W' ]
+  else
+    SUFFIXES = $KCODE == 'UTF8' ? [ '', 'W', 'A' ] : [ '', 'A', 'W' ]
+  end
 
   class Pointer
     extend FFI::DataConverter
 
@@ -3,7 +3,13 @@
 module Win32  
   class API < Module
     CONVENTION = FFI::Platform.windows? ? :stdcall : :default
-    SUFFIXES = $KCODE == 'UTF8' ? [ '', 'W', 'A' ] : [ '', 'A', 'W' ]
+
+    if RUBY_VERSION =~ /1\.9/
+      SUFFIXES = Encoding.default_internal == Encoding::UTF_8 ? [ '', 'W', 'A' ] : [ '', 'A', 'W' ]
+    else
+      SUFFIXES = $KCODE == 'UTF8' ? [ '', 'W', 'A' ] : [ '', 'A', 'W' ]
+    end
+
     TypeDefs = {
       'V' => :void,
       'S' => :string,