Added ZMQ_SHARED message option to zmq_msg_get()

AUTHORS

@@ -95,6 +95,7 @@ Taras Shpot
 Tero Marttila 
 Terry Wilson 
 Thijs Terlouw 
+Thomas Rodgers 
 Toralf Wittner 
 Tore Halvorsen 
 Trevor Bernard 

include/zmq.h

@@ -311,6 +311,7 @@ ZMQ_EXPORT const char *zmq_msg_gets (zmq_msg_t *msg, const char *property);
 /*  Message options                                                           */
 #define ZMQ_MORE 1
 #define ZMQ_SRCFD 2
+#define ZMQ_SHARED 3
 
 /*  Send/recv options.                                                        */
 #define ZMQ_DONTWAIT 1

src/zmq.cpp

@@ -629,6 +629,8 @@ int zmq_msg_get (zmq_msg_t *msg_, int property_)
         case ZMQ_SRCFD:
             // warning: int64_t to int
             return ((zmq::msg_t*) msg_)->fd ();
+        case ZMQ_SHARED:
+            return (((zmq::msg_t*) msg_)->flags () & zmq::msg_t::shared)? 1: 0;
         default:
             errno = EINVAL;
             return -1;