diff --git a/ChangeLog b/ChangeLog
index 60643cfb43..d178cf0b5e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Feb 16 20:59:10 2007  Koichi Sasada  <ko1@atdot.net>
+
+	* intern.h: add a prototype of rb_sym_to_s().
+
 Fri Feb 16 19:24:22 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* math.c (math_log): update document to mention second optional
diff --git a/intern.h b/intern.h
index c4a0c2c042..d1d23ad3d6 100644
--- a/intern.h
+++ b/intern.h
@@ -528,6 +528,7 @@ void rb_str_associate(VALUE, VALUE);
 VALUE rb_str_associated(VALUE);
 void rb_str_setter(VALUE, ID, VALUE*);
 VALUE rb_str_intern(VALUE);
+VALUE rb_sym_to_s(VALUE);
 /* struct.c */
 VALUE rb_struct_new(VALUE, ...);
 VALUE rb_struct_define(const char*, ...);