diff --git a/src/support/unicode.h b/src/support/unicode.h
index 10b34ead70..e04f3b6ebb 100644
--- a/src/support/unicode.h
+++ b/src/support/unicode.h
@@ -56,6 +56,8 @@ private:
 	boost::scoped_ptr<Private> pimpl_;
 };
 
+/// This is implemented in lyx_main.C for the LyX program 
+/// and in client.C for the LyX client program.
 extern IconvProcessor & utf8ToUcs4();
 
 // A single codepoint conversion for utf8_to_ucs4 does not make