diff --git a/src/transport.h b/src/transport.h
index 7d590e0..a7f43db 100644
--- a/src/transport.h
+++ b/src/transport.h
@@ -37,7 +37,6 @@
 /*  This is the API between the nanomsg core and individual transports. */
 
 struct nn_sock;
-struct nn_cp;
 
 /******************************************************************************/
 /*  Container for transport-specific socket options.                          */