diff --git a/ChangeLog b/ChangeLog
index 8df5005980..fe1281b1b2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Jun  6 14:09:08 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* include/ruby/defines.h (rb_inifinity, rb_nan): export for Windows.
+
 Mon Jun  6 10:54:45 2011  Shota Fukumori  <sorah@tubusu.net>
 
 	* lib/test/unit.rb(Test::Unit::Runner#puke):
diff --git a/include/ruby/defines.h b/include/ruby/defines.h
index 02ea2e0856..c9d6db2f6b 100644
--- a/include/ruby/defines.h
+++ b/include/ruby/defines.h
@@ -137,7 +137,7 @@ void xfree(void*);
 # define HAVE_INFINITY
 #else
 /** @internal */
-extern const unsigned char rb_infinity[];
+RUBY_EXTERN const unsigned char rb_infinity[];
 # define INFINITY (*(float *)rb_infinity)
 #endif
 
@@ -145,7 +145,7 @@ extern const unsigned char rb_infinity[];
 # define HAVE_NAN
 #else
 /** @internal */
-extern const unsigned char rb_nan[];
+RUBY_EXTERN const unsigned char rb_nan[];
 # define NAN (*(float *)rb_nan)
 #endif