diff --git a/include/libtorrent/alert_types.hpp b/include/libtorrent/alert_types.hpp
index eea2d43fc..52a3b649a 100644
--- a/include/libtorrent/alert_types.hpp
+++ b/include/libtorrent/alert_types.hpp
@@ -39,7 +39,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/config.hpp"
 #include "libtorrent/assert.hpp"
 #include "libtorrent/identify_client.hpp"
-//#include "libtorrent/socket_io.hpp"
 #include "libtorrent/address.hpp"
 
 namespace libtorrent
diff --git a/include/libtorrent/error.hpp b/include/libtorrent/error.hpp
index 19860e027..754966be3 100644
--- a/include/libtorrent/error.hpp
+++ b/include/libtorrent/error.hpp
@@ -34,6 +34,12 @@ POSSIBILITY OF SUCH DAMAGE.
 #define TORRENT_ERROR_HPP_INCLUDED
 
 #include <boost/version.hpp>
+#include "libtorrent/config.hpp"
+
+#if defined TORRENT_WINDOWS || defined TORRENT_CYGWIN
+// asio assumes that the windows error codes are defined already
+#include <winsock2.h>
+#endif
 
 #if BOOST_VERSION < 103500
 #include <asio/error.hpp>
diff --git a/include/libtorrent/error_code.hpp b/include/libtorrent/error_code.hpp
index 737f863d6..bad3237b0 100644
--- a/include/libtorrent/error_code.hpp
+++ b/include/libtorrent/error_code.hpp
@@ -34,6 +34,12 @@ POSSIBILITY OF SUCH DAMAGE.
 #define TORRENT_ERROR_CODE_HPP_INCLUDED
 
 #include <boost/version.hpp>
+#include "libtorrent/config.hpp"
+
+#if defined TORRENT_WINDOWS || defined TORRENT_CYGWIN
+// asio assumes that the windows error codes are defined already
+#include <winsock2.h>
+#endif
 
 #if BOOST_VERSION < 103500
 #include <asio/error_code.hpp>