1 files changed, 6 insertions, 0 deletions
diff --git a/bindings/c/zmq.h b/bindings/c/zmq.h
index 9b11a1d..a65926e 100644
--- a/bindings/c/zmq.h
+++ b/bindings/c/zmq.h
@@ -188,6 +188,12 @@ ZMQ_EXPORT int zmq_term (void *context);
 //  the peer that issued the last received request.
 #define ZMQ_REP 4
 
+//  Socket to receive messages from up the stream.
+#define ZMQ_UPSTREAM 5
+
+//  Socket to send messages downstream.
+#define ZMQ_DOWNSTREAM 6
+
 //  Open a socket. 'type' is one of the socket types defined above.
 //
 //  Errors: EINVAL - invalid socket type.