diff --git a/include/uv-errno.h b/include/uv-errno.h
index f5ef8470..19e2267b 100644
--- a/include/uv-errno.h
+++ b/include/uv-errno.h
@@ -376,4 +376,10 @@
 # define UV__EFBIG (-4036)
 #endif
 
+#if defined(ENOPROTOOPT) && !defined(_WIN32)
+# define UV__ENOPROTOOPT (-ENOPROTOOPT)
+#else
+# define UV__ENOPROTOOPT (-4035)
+#endif
+
 #endif /* UV_ERRNO_H_ */
diff --git a/include/uv.h b/include/uv.h
index c8536c23..c99e5fac 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -114,6 +114,7 @@ extern "C" {
   XX(ENOENT, "no such file or directory")                                     \
   XX(ENOMEM, "not enough memory")                                             \
   XX(ENONET, "machine is not on the network")                                 \
+  XX(ENOPROTOOPT, "protocol not available")                                   \
   XX(ENOSPC, "no space left on device")                                       \
   XX(ENOSYS, "function not implemented")                                      \
   XX(ENOTCONN, "socket is not connected")                                     \