Renamed new socket options to be clearer

* ZMQ_REQ_STRICT was negative option (default 1) which goes against
  the standard, where defaults are zero. I renamed this to
  ZMQ_REQ_RELAXED.

* ZMQ_REQ_REQUEST_IDS felt clumsy and describes the technical solution
  rather than the problem/requirement. I changed to ZMQ_REQ_CORRELATE
  which seems more explicit.

tests/test_req_correlate.cpp

@@ -0,0 +1,177 @@
+/*
+    Copyright (c) 2007-2013 Contributors as noted in the AUTHORS file
+
+    This file is part of 0MQ.
+
+    0MQ is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    0MQ is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "testutil.hpp"
+
+int main (void)
+{
+    setup_test_environment();
+    void *ctx = zmq_ctx_new ();
+    assert (ctx);
+
+    void *req = zmq_socket (ctx, ZMQ_REQ);
+    assert (req);
+
+    void *router = zmq_socket (ctx, ZMQ_ROUTER);
+    assert (router);
+
+    int enabled = 1;
+    int rc = zmq_setsockopt (req, ZMQ_REQ_CORRELATE, &enabled, sizeof (int));
+    assert (rc == 0);
+
+    int rcvtimeo = 100;
+    rc = zmq_setsockopt (req, ZMQ_RCVTIMEO, &rcvtimeo, sizeof (int));
+    assert (rc == 0);
+
+    rc = zmq_connect (req, "tcp://localhost:5555");
+    assert (rc == 0);
+
+    rc = zmq_bind (router, "tcp://127.0.0.1:5555");
+    assert (rc == 0);
+
+    // Send a multi-part request.
+    s_send_seq (req, "ABC", "DEF", SEQ_END);
+
+    zmq_msg_t msg;
+    zmq_msg_init (&msg);
+
+    // Receive peer identity
+    rc = zmq_msg_recv (&msg, router, 0);
+    assert (rc != -1);
+    assert (zmq_msg_size (&msg) > 0);
+    zmq_msg_t peer_id_msg;
+    zmq_msg_init (&peer_id_msg);
+    zmq_msg_copy (&peer_id_msg, &msg);
+
+    int more = 0;
+    size_t more_size = sizeof (more);
+    rc = zmq_getsockopt (router, ZMQ_RCVMORE, &more, &more_size);
+    assert (rc == 0);
+    assert (more);
+
+    // Receive request id 1
+    rc = zmq_msg_recv (&msg, router, 0);
+    assert (rc != -1);
+    assert (zmq_msg_size (&msg) == sizeof(uint32_t));
+    uint32_t req_id = *static_cast<uint32_t *> (zmq_msg_data (&msg));
+    zmq_msg_t req_id_msg;
+    zmq_msg_init (&req_id_msg);
+    zmq_msg_copy (&req_id_msg, &msg);
+
+    more = 0;
+    more_size = sizeof (more);
+    rc = zmq_getsockopt (router, ZMQ_RCVMORE, &more, &more_size);
+    assert (rc == 0);
+    assert (more);
+
+    // Receive the rest.
+    s_recv_seq (router, 0, "ABC", "DEF", SEQ_END);
+
+    // Send back a bad reply: correct req id
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    zmq_msg_copy (&msg, &req_id_msg);
+    rc = zmq_msg_send (&msg, router, 0);
+    assert (rc != -1);
+
+    // Send back a bad reply: wrong req id
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    uint32_t bad_req_id = req_id + 1;
+    zmq_msg_init_data (&msg, &bad_req_id, sizeof (uint32_t), NULL, NULL);
+    rc = zmq_msg_send (&msg, router, 0);
+    assert (rc != -1);
+
+    // Send back a bad reply: correct req id, 0
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    zmq_msg_copy (&msg, &req_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    s_send_seq (router, 0, SEQ_END);
+
+    // Send back a bad reply: correct req id, garbage
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    zmq_msg_copy (&msg, &req_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    s_send_seq (router, "FOO", SEQ_END);
+
+    // Send back a bad reply: wrong req id, 0
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    zmq_msg_init_data (&msg, &bad_req_id, sizeof (uint32_t), NULL, NULL);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    s_send_seq (router, 0, SEQ_END);
+
+    // Send back a bad reply: correct req id, garbage, data
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    zmq_msg_copy (&msg, &req_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    s_send_seq (router, "FOO", "DATA", SEQ_END);
+
+    // Send back a bad reply: wrong req id, 0, data
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    zmq_msg_init_data (&msg, &bad_req_id, sizeof (uint32_t), NULL, NULL);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    s_send_seq (router, 0, "DATA", SEQ_END);
+
+    // Send back a good reply.
+    zmq_msg_copy (&msg, &peer_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    zmq_msg_copy (&msg, &req_id_msg);
+    rc = zmq_msg_send (&msg, router, ZMQ_SNDMORE);
+    assert (rc != -1);
+    s_send_seq (router, 0, "GHI", SEQ_END);
+
+    // Receive reply. If any of the other messages got through, we wouldn't see
+    // this particular data.
+    s_recv_seq (req, "GHI", SEQ_END);
+
+    rc = zmq_msg_close (&msg);
+    assert (rc == 0);
+
+    rc = zmq_msg_close (&peer_id_msg);
+    assert (rc == 0);
+
+    rc = zmq_msg_close (&req_id_msg);
+    assert (rc == 0);
+
+    close_zero_linger (req);
+    close_zero_linger (router);
+
+    rc = zmq_ctx_term (ctx);
+    assert (rc == 0);
+
+    return 0;
+}