Change zmq_recv to zmg_msg_recv since zmq_msg_t is only used with the zmg_msg_recv style functions.

doc/zmq_msg_init.txt

@@ -16,7 +16,7 @@ DESCRIPTION
 -----------
 The _zmq_msg_init()_ function shall initialise the message object referenced by
 'msg' to represent an empty message.  This function is most useful when called
-before receiving a message with _zmq_recv()_.
+before receiving a message with _zmq_msg_recv()_.
 
 CAUTION: Never access 'zmq_msg_t' members directly, instead always use the
 _zmq_msg_ family of functions.
@@ -43,7 +43,7 @@ EXAMPLE
 zmq_msg_t msg;
 rc = zmq_msg_init (&msg);
 assert (rc == 0);
-int nbytes = zmq_recv (socket, &msg, 0);
+int nbytes = zmq_msg_recv (socket, &msg, 0);
 assert (nbytes != -1);
 ----