diff --git a/ChangeLog b/ChangeLog
index 3065786261..01d7960a41 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jan  1 20:50:09 2009  URABE Shyouhei  <shyouhei@ruby-lang.org>
+
+	* process.c (before_exec): it makes no sense for a conditional
+	  expression to return a void value.
+
 Thu Jan  1 20:47:09 2009  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/socket.c (sock_s_getaddrinfo): use family_to_int.
diff --git a/process.c b/process.c
index ac0ec0605e..ed84d516aa 100644
--- a/process.c
+++ b/process.c
@@ -973,7 +973,7 @@ void rb_thread_reset_timer_thread(void);
 static int forked_child = 0;
 
 #define before_exec() \
-  (rb_enable_interrupt(), forked_child ? 0 : rb_thread_stop_timer_thread())
+    (rb_enable_interrupt(), (forked_child ? 0 : (rb_thread_stop_timer_thread(), 1)))
 #define after_exec() \
   (rb_thread_reset_timer_thread(), rb_thread_start_timer_thread(), forked_child = 0, rb_disable_interrupt())
 #define before_fork() before_exec()