diff --git a/ChangeLog b/ChangeLog
index bc6d8cfe58..ec0a19442d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Oct 31 22:04:54 2011  Tanaka Akira  <akr@fsij.org>
+
+	* ext/dbm/dbm.c (fdbm_initialize): use O_CLOEXEC if available.
+
 Mon Oct 31 21:47:48 2011  Tanaka Akira  <akr@fsij.org>
 
 	* include/ruby/intern.h (rb_fd_fix_cloexec): renamed from
diff --git a/ext/dbm/dbm.c b/ext/dbm/dbm.c
index 6d5396066d..9b52a4eac2 100644
--- a/ext/dbm/dbm.c
+++ b/ext/dbm/dbm.c
@@ -137,20 +137,23 @@ fdbm_initialize(int argc, VALUE *argv, VALUE obj)
 
     FilePathValue(file);
 
+#ifndef O_CLOEXEC
+#   define O_CLOEXEC 0
+#endif
     if (flags & RUBY_DBM_RW_BIT) {
         flags &= ~RUBY_DBM_RW_BIT;
-        dbm = dbm_open(RSTRING_PTR(file), flags, mode);
+        dbm = dbm_open(RSTRING_PTR(file), flags|O_CLOEXEC, mode);
     }
     else {
         dbm = 0;
         if (mode >= 0) {
-            dbm = dbm_open(RSTRING_PTR(file), O_RDWR|O_CREAT, mode);
+            dbm = dbm_open(RSTRING_PTR(file), O_RDWR|O_CREAT|O_CLOEXEC, mode);
         }
         if (!dbm) {
-            dbm = dbm_open(RSTRING_PTR(file), O_RDWR, 0);
+            dbm = dbm_open(RSTRING_PTR(file), O_RDWR|O_CLOEXEC, 0);
         }
         if (!dbm) {
-            dbm = dbm_open(RSTRING_PTR(file), O_RDONLY, 0);
+            dbm = dbm_open(RSTRING_PTR(file), O_RDONLY|O_CLOEXEC, 0);
         }
     }