posix: handle different errno for OSX when setting control lines on open, fixes #133
diff --git a/CHANGES.rst b/CHANGES.rst
index 08b9df9..9166c18 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -646,3 +646,11 @@
 Bugfixes (win32):
 
 - win32: handle errors of GetOverlappedResult in read(), fixes #121
+
+Version 3.x.x   2016-xx-xx
+--------------------------
+Bugfixes (posix):
+
+- [#133] _update_dtr_state throws Inappropriate ioctl for virtual serial
+  port created by socat on OS X
+
diff --git a/serial/serialposix.py b/serial/serialposix.py
index 0bf3df5..913b643 100644
--- a/serial/serialposix.py
+++ b/serial/serialposix.py
@@ -266,7 +266,7 @@
             if not self._rtscts:
                 self._update_rts_state()
         except IOError as e:
-            if e.errno == 22:  # ignore Invalid argument
+            if e.errno in (22, 25):  # ignore Invalid argument and Inappropriate ioctl
                 pass
             else:
                 raise