1 files changed, 5 insertions, 1 deletions
diff --git a/ace/OS.i b/ace/OS.i
index 6ffc6f973ac..7684b82e0e0 100644
--- a/ace/OS.i
+++ b/ace/OS.i
@@ -1598,7 +1598,11 @@ ACE_OS::mutex_init (ACE_mutex_t *m,
       if (m->proc_mutex_ == 0)
         ACE_FAIL_RETURN (-1);
       else
-        return 0;
+        {
+          // Make sure to set errno to ERROR_ALREADY_EXISTS if necessary.
+          ACE_OS::set_errno_to_last_error ();
+          return 0;
+        }
     case USYNC_THREAD:
       return ACE_OS::thread_mutex_init (&m->thr_mutex_,
                                         type,