diff --git a/ChangeLog b/ChangeLog
index 1470ff6bbe..fd015593cd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Oct 29 14:26:56 2011  Tanaka Akira  <akr@fsij.org>
+
+	* io.c (rb_cloexec_open): use O_CLOEXEC if available.
+
 Sat Oct 29 12:57:15 2011  Tanaka Akira  <akr@fsij.org>
 
 	* process.c (ruby_setsid): use rb_cloexec_open.
diff --git a/io.c b/io.c
index 806d095139..98484e8958 100644
--- a/io.c
+++ b/io.c
@@ -191,6 +191,9 @@ int
 rb_cloexec_open(const char *pathname, int flags, mode_t mode)
 {
     int ret;
+#ifdef O_CLOEXEC
+    flags |= O_CLOEXEC;
+#endif
     ret = open(pathname, flags, mode);
     if (ret == -1) return -1;
     fd_set_cloexec(ret);