diff --git a/ChangeLog b/ChangeLog
index 99b7b0bfef..fb9a06f9cb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Oct  2 05:40:05 2014  Eric Wong  <e@80x24.org>
+
+	* ruby.h: set rb_event_flag_t to uint32_t
+	  [ruby-core:65315] [misc #10249]
+
 Thu Oct  2 05:32:17 2014  Eric Wong  <e@80x24.org>
 
 	* io.c (fptr_finalize): free memory before GC sweep
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index ff6c708ba9..8171ab3e32 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -1728,7 +1728,7 @@ int ruby_native_thread_p(void);
 #define RUBY_INTERNAL_EVENT_OBJSPACE_MASK  0x7f00000
 #define RUBY_INTERNAL_EVENT_MASK          0xfffe0000
 
-typedef unsigned long rb_event_flag_t;
+typedef uint32_t rb_event_flag_t;
 typedef void (*rb_event_hook_func_t)(rb_event_flag_t evflag, VALUE data, VALUE self, ID mid, VALUE klass);
 
 #define RB_EVENT_HOOKS_HAVE_CALLBACK_DATA 1