Problem: use of unqualified "id" in code example

Solution: use "routing_id" instead

doc/zmq_socket.txt

@@ -559,16 +559,16 @@ void *socket = zmq_socket (ctx, ZMQ_STREAM);
 assert (socket);
 int rc = zmq_bind (socket, "tcp://*:8080");
 assert (rc == 0);
-/* Data structure to hold the ZMQ_STREAM ID */
-uint8_t id [256];
-size_t id_size = 256;
+/* Data structure to hold the ZMQ_STREAM routing id */
+uint8_t routing_id [256];
+size_t routing_id_size = 256;
 /* Data structure to hold the ZMQ_STREAM received data */
 uint8_t raw [256];
 size_t raw_size = 256;
 while (1) {
-	/*  Get HTTP request; ID frame and then request */
-	id_size = zmq_recv (socket, id, 256, 0);
-	assert (id_size > 0);
+	/*  Get HTTP request; routing id frame and then request */
+	routing_id_size = zmq_recv (socket, routing_id, 256, 0);
+	assert (routing_id_size > 0);
 	do {
 		raw_size = zmq_recv (socket, raw, 256, 0);
 		assert (raw_size >= 0);
@@ -579,11 +579,11 @@ while (1) {
 		"Content-Type: text/plain\r\n"
 		"\r\n"
 		"Hello, World!";
-	/* Sends the ID frame followed by the response */
-	zmq_send (socket, id, id_size, ZMQ_SNDMORE);
+	/* Sends the routing id frame followed by the response */
+	zmq_send (socket, routing_id, routing_id_size, ZMQ_SNDMORE);
 	zmq_send (socket, http_response, strlen (http_response), 0);
-	/* Closes the connection by sending the ID frame followed by a zero response */
-	zmq_send (socket, id, id_size, ZMQ_SNDMORE);
+	/* Closes the connection by sending the routing id frame followed by a zero response */
+	zmq_send (socket, routing_id, routing_id_size, ZMQ_SNDMORE);
 	zmq_send (socket, 0, 0, 0);
 }
 zmq_close (socket);