diff --git a/ChangeLog b/ChangeLog
index daf1020117..8273fe6ed6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Jul 10 14:09:05 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/coverage/coverage.c (rb_coverage_start): return nil.
+
 Thu Jul 10 12:41:56 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* thread.c (rb_thread_wait_for): fixed variable name.
diff --git a/ext/coverage/coverage.c b/ext/coverage/coverage.c
index 3c6746f7aa..802b505032 100644
--- a/ext/coverage/coverage.c
+++ b/ext/coverage/coverage.c
@@ -30,6 +30,7 @@ rb_coverage_start(VALUE klass)
 	RBASIC(coverages)->klass = 0;
 	rb_set_coverages(coverages);
     }
+    return Qnil;
 }
 
 static int