diff --git a/docs/src/errors.rst b/docs/src/errors.rst
index c7240f35..a2e94d96 100644
--- a/docs/src/errors.rst
+++ b/docs/src/errors.rst
@@ -339,6 +339,9 @@ Error constants
 
     socket type not supported
 
+.. c:macro:: UV_EUNATCH
+
+    protocol driver not attached
 
 API
 ---
diff --git a/include/uv.h b/include/uv.h
index f68ff083..02397dd0 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -156,6 +156,7 @@ struct uv__queue {
   XX(EILSEQ, "illegal byte sequence")                                         \
   XX(ESOCKTNOSUPPORT, "socket type not supported")                            \
   XX(ENODATA, "no data available")                                            \
+  XX(EUNATCH, "protocol driver not attached")                                 \
 
 #define UV_HANDLE_TYPE_MAP(XX)                                                \
   XX(ASYNC, async)                                                            \
diff --git a/include/uv/errno.h b/include/uv/errno.h
index 648e493d..127278ef 100644
--- a/include/uv/errno.h
+++ b/include/uv/errno.h
@@ -468,4 +468,10 @@
 # define UV__ENODATA (-4024)
 #endif
 
+#if defined(EUNATCH) && !defined(_WIN32)
+# define UV__EUNATCH UV__ERR(EUNATCH)
+#else
+# define UV__EUNATCH (-4023)
+#endif
+
 #endif /* UV_ERRNO_H_ */