Common 6b5db53: Update zmq.hpp, TCPReceiveServer, EDI decoder and output

18 files changed, 2099 insertions, 496 deletions

diff --git a/lib/RemoteControl.cpp b/lib/RemoteControl.cpp
index 4adb90c..9ca8d22 100644
--- a/lib/RemoteControl.cpp
+++ b/lib/RemoteControl.cpp
@@ -29,6 +29,7 @@
 #include <algorithm>
 
 #include "RemoteControl.h"
+#include "zmq.hpp"
 
 using namespace std;
 
@@ -424,7 +425,7 @@ void RemoteControllerZmq::recv_all(zmq::socket_t& pSocket, std::vector<std::stri
     bool more = true;
     do {
         zmq::message_t msg;
-        pSocket.recv(&msg);
+        pSocket.recv(msg);
         std::string incoming((char*)msg.data(), msg.size());
         message.push_back(incoming);
         more = msg.more();
@@ -436,7 +437,7 @@ void RemoteControllerZmq::send_ok_reply(zmq::socket_t &pSocket)
     zmq::message_t msg(2);
     char repCode[2] = {'o', 'k'};
     memcpy ((void*) msg.data(), repCode, 2);
-    pSocket.send(msg, 0);
+    pSocket.send(msg, zmq::send_flags::none);
 }
 
 void RemoteControllerZmq::send_fail_reply(zmq::socket_t &pSocket, const std::string &error)
@@ -444,11 +445,11 @@ void RemoteControllerZmq::send_fail_reply(zmq::socket_t &pSocket, const std::str
     zmq::message_t msg1(4);
     char repCode[4] = {'f', 'a', 'i', 'l'};
     memcpy ((void*) msg1.data(), repCode, 4);
-    pSocket.send(msg1, ZMQ_SNDMORE);
+    pSocket.send(msg1, zmq::send_flags::sndmore);
 
     zmq::message_t msg2(error.length());
     memcpy ((void*) msg2.data(), error.c_str(), error.length());
-    pSocket.send(msg2, 0);
+    pSocket.send(msg2, zmq::send_flags::none);
 }
 
 void RemoteControllerZmq::process()
@@ -508,8 +509,7 @@ void RemoteControllerZmq::process()
                         zmq::message_t zmsg(ss.str().size());
                         memcpy ((void*) zmsg.data(), msg_s.data(), msg_s.size());
 
-                        int flag = (--cohort_size > 0) ? ZMQ_SNDMORE : 0;
-                        repSocket.send(zmsg, flag);
+                        repSocket.send(zmsg, (--cohort_size > 0) ? zmq::send_flags::sndmore : zmq::send_flags::none);
                     }
                 }
                 else if (msg.size() == 2 && command == "show") {
@@ -523,8 +523,7 @@ void RemoteControllerZmq::process()
                             zmq::message_t zmsg(ss.str().size());
                             memcpy(zmsg.data(), ss.str().data(), ss.str().size());
 
-                            int flag = (--r_size > 0) ? ZMQ_SNDMORE : 0;
-                            repSocket.send(zmsg, flag);
+                            repSocket.send(zmsg, (--r_size > 0) ? zmq::send_flags::sndmore : zmq::send_flags::none);
                         }
                     }
                     catch (const ParameterError &err) {
@@ -539,7 +538,7 @@ void RemoteControllerZmq::process()
                         std::string value = rcs.get_param(module, parameter);
                         zmq::message_t zmsg(value.size());
                         memcpy ((void*) zmsg.data(), value.data(), value.size());
-                        repSocket.send(zmsg, 0);
+                        repSocket.send(zmsg, zmq::send_flags::none);
                     }
                     catch (const ParameterError &err) {
                         send_fail_reply(repSocket, err.what());
@@ -576,4 +575,3 @@ void RemoteControllerZmq::process()
 }
 
 #endif
-
diff --git a/lib/Socket.cpp b/lib/Socket.cpp
index d41ed1c..6a20429 100644
--- a/lib/Socket.cpp
+++ b/lib/Socket.cpp
@@ -862,9 +862,9 @@ TCPReceiveServer::~TCPReceiveServer()
     }
 }
 
-vector<uint8_t> TCPReceiveServer::receive()
+shared_ptr<TCPReceiveMessage> TCPReceiveServer::receive()
 {
-    vector<uint8_t> buffer;
+    shared_ptr<TCPReceiveMessage> buffer = make_shared<TCPReceiveMessageEmpty>();
     m_queue.try_pop(buffer);
 
     // we can ignore try_pop()'s return value, because
@@ -892,11 +892,12 @@ void TCPReceiveServer::process()
                 }
                 else if (r == 0) {
                     sock.close();
+                    m_queue.push(make_shared<TCPReceiveMessageDisconnected>());
                     break;
                 }
                 else {
                     buf.resize(r);
-                    m_queue.push(move(buf));
+                    m_queue.push(make_shared<TCPReceiveMessageData>(move(buf)));
                 }
             }
             catch (const TCPSocket::Interrupted&) {
@@ -905,6 +906,11 @@ void TCPReceiveServer::process()
             catch (const TCPSocket::Timeout&) {
                 num_timeouts++;
             }
+            catch (const runtime_error& e) {
+                sock.close();
+                // TODO replace fprintf
+                fprintf(stderr, "TCP Receiver restarted after error: %s\n", e.what());
+            }
 
             if (num_timeouts > max_num_timeouts) {
                 sock.close();
diff --git a/lib/Socket.h b/lib/Socket.h
index 8881be3..2291dd5 100644
--- a/lib/Socket.h
+++ b/lib/Socket.h
@@ -30,11 +30,12 @@
 
 #include "ThreadsafeQueue.h"
 #include <cstdlib>
-#include <iostream>
-#include <vector>
 #include <atomic>
-#include <thread>
+#include <iostream>
 #include <list>
+#include <memory>
+#include <thread>
+#include <vector>
 
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -265,6 +266,14 @@ class TCPDataDispatcher
         std::list<TCPConnection> m_connections;
 };
 
+struct TCPReceiveMessage { virtual ~TCPReceiveMessage() {}; };
+struct TCPReceiveMessageDisconnected : public TCPReceiveMessage { };
+struct TCPReceiveMessageEmpty : public TCPReceiveMessage { };
+struct TCPReceiveMessageData : public TCPReceiveMessage {
+    TCPReceiveMessageData(std::vector<uint8_t> d) : data(d) {};
+    std::vector<uint8_t> data;
+};
+
 /* A TCP Server to receive data, which abstracts the handling of connects and disconnects.
  */
 class TCPReceiveServer {
@@ -276,15 +285,15 @@ class TCPReceiveServer {
 
         void start(int listen_port, const std::string& address);
 
-        // Return a vector that contains up to blocksize bytes of data, or
-        // and empty vector if no data is available.
-        std::vector<uint8_t> receive();
+        // Return an instance of a subclass of TCPReceiveMessage that contains up to blocksize
+        // bytes of data, or TCPReceiveMessageEmpty if no data is available.
+        std::shared_ptr<TCPReceiveMessage> receive();
 
     private:
         void process();
 
         size_t m_blocksize = 0;
-        ThreadsafeQueue<std::vector<uint8_t> > m_queue;
+        ThreadsafeQueue<std::shared_ptr<TCPReceiveMessage> > m_queue;
         std::atomic<bool> m_running = ATOMIC_VAR_INIT(false);
         std::string m_exception_data;
         std::thread m_listener_thread;
diff --git a/lib/edi/PFT.cpp b/lib/edi/PFT.cpp
index 158b206..85d6b63 100644
--- a/lib/edi/PFT.cpp
+++ b/lib/edi/PFT.cpp
@@ -23,6 +23,7 @@
 #include <cstdio>
 #include <cassert>
 #include <cstring>
+#include <cmath>
 #include <sstream>
 #include <stdexcept>
 #include <algorithm>
@@ -109,11 +110,18 @@ class FECDecoder {
 
 size_t Fragment::loadData(const std::vector<uint8_t> &buf)
 {
+    return loadData(buf, 0);
+}
+
+size_t Fragment::loadData(const std::vector<uint8_t> &buf, int received_on_port)
+{
     const size_t header_len = 14;
     if (buf.size() < header_len) {
         return 0;
     }
 
+    this->received_on_port = received_on_port;
+
     size_t index = 0;
 
     // Parse PFT Fragment Header (ETSI TS 102 821 V1.4.1 ch7.1)
@@ -461,6 +469,32 @@ std::string AFBuilder::visualise() const
     return ss.str();
 }
 
+std::string AFBuilder::visualise_fragment_origins() const
+{
+    stringstream ss;
+    if (_fragments.size() == 0) {
+        return "No fragments";
+    }
+    else {
+        ss << _fragments.size() << " fragments: ";
+    }
+
+    std::map<int, size_t> port_count;
+
+    for (const auto& f : _fragments) {
+        port_count[f.second.received_on_port]++;
+    }
+
+    for (const auto& p : port_count) {
+        ss << "p" << p.first << " " <<
+            std::round(100.0 * ((double)p.second) / (double)_fragments.size()) << "% ";
+    }
+
+    ss << "\n";
+
+    return ss.str();
+}
+
 void PFT::pushPFTFrag(const Fragment &fragment)
 {
     // Start decoding the first pseq we receive. In normal
@@ -518,6 +552,9 @@ std::vector<uint8_t> PFT::getNextAFPacket()
     if (builder.canAttemptToDecode() == dar_t::yes) {
         auto afpacket = builder.extractAF();
         assert(not afpacket.empty());
+        if (m_verbose) {
+            etiLog.level(debug) << "Fragment origin stats: " << builder.visualise_fragment_origins();
+        }
         incrementNextPseq();
         return afpacket;
     }
@@ -533,6 +570,9 @@ std::vector<uint8_t> PFT::getNextAFPacket()
             if (afpacket.empty()) {
                 etiLog.log(debug,"pseq %d timed out after RS", m_next_pseq);
             }
+            if (m_verbose) {
+                etiLog.level(debug) << "Fragment origin stats: " << builder.visualise_fragment_origins();
+            }
             incrementNextPseq();
             return afpacket;
         }
diff --git a/lib/edi/PFT.hpp b/lib/edi/PFT.hpp
index 208fd70..08dca45 100644
--- a/lib/edi/PFT.hpp
+++ b/lib/edi/PFT.hpp
@@ -36,11 +36,14 @@ using findex_t = uint32_t; // findex is a 24-bit value
 class Fragment
 {
     public:
+        int received_on_port = 0;
+
         // Load the data for one fragment from buf into
         // the Fragment.
         // \returns the number of bytes of useful data found in buf
         // A non-zero return value doesn't imply a valid fragment
         // the isValid() method must be used to verify this.
+        size_t loadData(const std::vector<uint8_t> &buf, int received_on_port);
         size_t loadData(const std::vector<uint8_t> &buf);
 
         bool isValid() const { return _valid; }
@@ -111,7 +114,9 @@ class AFBuilder
                 return {_fragments.size(), _Fcount};
             }
 
-        std::string visualise(void) const;
+        std::string visualise() const;
+
+        std::string visualise_fragment_origins() const;
 
         /* The user of this instance can keep track of the lifetime of this
          * builder
diff --git a/lib/edi/STIDecoder.cpp b/lib/edi/STIDecoder.cpp
index b6b9878..99f7c11 100644
--- a/lib/edi/STIDecoder.cpp
+++ b/lib/edi/STIDecoder.cpp
@@ -60,9 +60,9 @@ void STIDecoder::push_bytes(const vector<uint8_t> &buf)
     m_dispatcher.push_bytes(buf);
 }
 
-void STIDecoder::push_packet(const vector<uint8_t> &buf)
+void STIDecoder::push_packet(Packet &pack)
 {
-    m_dispatcher.push_packet(buf);
+    m_dispatcher.push_packet(pack);
 }
 
 void STIDecoder::setMaxDelay(int num_af_packets)
@@ -107,7 +107,7 @@ bool STIDecoder::decode_dsti(const std::vector<uint8_t>& value, const tag_name_t
     uint8_t dfcth = (dstiHeader >> 8) & 0x1F;
     uint8_t dfctl = dstiHeader & 0xFF;
 
-    md.dflc = dfcth * 250 + dfctl; // modulo 5000 counter
+    md.dlfc = dfcth * 250 + dfctl; // modulo 5000 counter
 
     const size_t expected_length = 2 +
         (md.stihf ? 3 : 0) +
@@ -115,10 +115,14 @@ bool STIDecoder::decode_dsti(const std::vector<uint8_t>& value, const tag_name_t
         (md.rfadf ? 9 : 0);
 
     if (value.size() != expected_length) {
-        throw std::runtime_error("EDI dsti: decoding error:"
-                "value.size() != expected_length: " +
-               to_string(value.size()) + " " +
-               to_string(expected_length));
+        etiLog.level(warn) << "EDI dsti: decoding error: " <<
+            "value.size() != expected_length: " <<
+               value.size() << " " <<
+               expected_length << " " <<
+               (md.stihf ? "STIHF " : " ") <<
+               (md.atstf ? "ATSTF " : " ") <<
+               (md.rfadf ? "RFADF " : " ");
+        return false;
     }
 
     if (md.stihf) {
diff --git a/lib/edi/STIDecoder.hpp b/lib/edi/STIDecoder.hpp
index 9d55728..28887f2 100644
--- a/lib/edi/STIDecoder.hpp
+++ b/lib/edi/STIDecoder.hpp
@@ -34,7 +34,7 @@ struct sti_management_data {
     bool stihf;
     bool atstf;
     bool rfadf;
-    uint16_t dflc;
+    uint16_t dlfc;
 
     uint32_t tsta;
 };
@@ -104,14 +104,15 @@ class STIDecoder {
 
         /* Push bytes into the decoder. The buf can contain more
          * than a single packet. This is useful when reading from streams
-         * (files, TCP)
+         * (files, TCP). Pushing an empty buf will clear the internal decoder
+         * state to ensure realignment (e.g. on stream reconnection)
          */
         void push_bytes(const std::vector<uint8_t> &buf);
 
         /* Push a complete packet into the decoder. Useful for UDP and other
          * datagram-oriented protocols.
          */
-        void push_packet(const std::vector<uint8_t> &buf);
+        void push_packet(Packet &pack);
 
         /* Set the maximum delay in number of AF Packets before we
          * abandon decoding a given pseq.
diff --git a/lib/edi/STIWriter.cpp b/lib/edi/STIWriter.cpp
index a7e4f20..29f0124 100644
--- a/lib/edi/STIWriter.cpp
+++ b/lib/edi/STIWriter.cpp
@@ -123,6 +123,7 @@ void STIWriter::assemble()
     // TODO check time validity
 
     sti_frame_t stiFrame;
+    stiFrame.dlfc = m_management_data.dlfc;
     stiFrame.frame = move(m_payload.istd);
     stiFrame.timestamp.seconds = m_seconds;
     stiFrame.timestamp.utco = m_utco;
diff --git a/lib/edi/STIWriter.hpp b/lib/edi/STIWriter.hpp
index fc08e97..a7a5cda 100644
--- a/lib/edi/STIWriter.hpp
+++ b/lib/edi/STIWriter.hpp
@@ -32,6 +32,7 @@ namespace EdiDecoder {
 
 struct sti_frame_t {
     std::vector<uint8_t> frame;
+    uint16_t dlfc;
     frame_timestamp_t timestamp;
     audio_level_data audio_levels;
     odr_version_data version_data;
diff --git a/lib/edi/common.cpp b/lib/edi/common.cpp
index 306261a..7907656 100644
--- a/lib/edi/common.cpp
+++ b/lib/edi/common.cpp
@@ -22,6 +22,7 @@
 #include "buffer_unpack.hpp"
 #include "Log.h"
 #include "crc.h"
+#include <algorithm>
 #include <sstream>
 #include <cassert>
 #include <cmath>
@@ -142,6 +143,12 @@ void TagDispatcher::set_verbose(bool verbose)
 
 void TagDispatcher::push_bytes(const vector<uint8_t> &buf)
 {
+    if (buf.empty()) {
+        m_input_data.clear();
+        m_last_seq_valid = false;
+        return;
+    }
+
     copy(buf.begin(), buf.end(), back_inserter(m_input_data));
 
     while (m_input_data.size() > 2) {
@@ -194,14 +201,16 @@ void TagDispatcher::push_bytes(const vector<uint8_t> &buf)
             }
         }
         else {
-            etiLog.log(warn,"Unknown %c!", *m_input_data.data());
+            etiLog.log(warn, "Unknown 0x%02x!", *m_input_data.data());
             m_input_data.erase(m_input_data.begin());
         }
     }
 }
 
-void TagDispatcher::push_packet(const vector<uint8_t> &buf)
+void TagDispatcher::push_packet(const Packet &packet)
 {
+    auto& buf = packet.buf;
+
     if (buf.size() < 2) {
         throw std::invalid_argument("Not enough bytes to read EDI packet header");
     }
@@ -216,7 +225,7 @@ void TagDispatcher::push_packet(const vector<uint8_t> &buf)
     }
     else if (buf[0] == 'P' and buf[1] == 'F') {
         PFT::Fragment fragment;
-        fragment.loadData(buf);
+        fragment.loadData(buf, packet.received_on_port);
 
         if (fragment.isValid()) {
             m_pft.pushPFTFrag(fragment);
@@ -232,11 +241,10 @@ void TagDispatcher::push_packet(const vector<uint8_t> &buf)
         }
     }
     else {
-        const char packettype[3] = {(char)buf[0], (char)buf[1], '\0'};
         std::stringstream ss;
-        ss << "Unknown EDI packet ";
-        ss << packettype;
-        throw std::invalid_argument(ss.str());
+        ss << "Unknown EDI packet " << std::hex << (int)buf[0] << " " << (int)buf[1];
+        m_ignored_tags.clear();
+        throw invalid_argument(ss.str());
     }
 }
 
@@ -268,6 +276,7 @@ decode_state_t TagDispatcher::decode_afpacket(
         const uint16_t expected_seq = m_last_seq + 1;
         if (expected_seq != seq) {
             etiLog.level(warn) << "EDI AF Packet sequence error, " << seq;
+            m_ignored_tags.clear();
         }
     }
     else {
@@ -303,8 +312,7 @@ decode_state_t TagDispatcher::decode_afpacket(
     uint16_t packet_crc = read_16b(input_data.begin() + AFPACKET_HEADER_LEN + taglength);
 
     if (packet_crc != crc) {
-        throw invalid_argument(
-                "AF Packet crc wrong");
+        throw invalid_argument("AF Packet crc wrong");
     }
     else {
         vector<uint8_t> payload(taglength);
@@ -379,7 +387,10 @@ bool TagDispatcher::decode_tagpacket(const vector<uint8_t> &payload)
         }
 
         if (not found) {
-            etiLog.log(warn, "Ignoring unknown TAG %s", tag.c_str());
+            if (std::find(m_ignored_tags.begin(), m_ignored_tags.end(), tag) == m_ignored_tags.end()) {
+                etiLog.log(warn, "Ignoring unknown TAG %s", tag.c_str());
+                m_ignored_tags.push_back(tag);
+            }
             break;
         }
 
diff --git a/lib/edi/common.hpp b/lib/edi/common.hpp
index c8c4bb3..14b91ba 100644
--- a/lib/edi/common.hpp
+++ b/lib/edi/common.hpp
@@ -60,6 +60,14 @@ using tag_name_t = std::array<uint8_t, 4>;
 
 std::string tag_name_to_human_readable(const tag_name_t& name);
 
+struct Packet {
+    std::vector<uint8_t> buf;
+    int received_on_port;
+
+    Packet(std::vector<uint8_t>&& b) : buf(b), received_on_port(0) { }
+    Packet() {}
+};
+
 /* The TagDispatcher takes care of decoding EDI, with or without PFT, and
  * will call functions when TAGs are encountered.
  *
@@ -72,17 +80,17 @@ class TagDispatcher {
 
         void set_verbose(bool verbose);
 
-
         /* Push bytes into the decoder. The buf can contain more
          * than a single packet. This is useful when reading from streams
-         * (files, TCP)
+         * (files, TCP). Pushing an empty buf will clear the internal decoder
+         * state to ensure realignment (e.g. on stream reconnection)
          */
         void push_bytes(const std::vector<uint8_t> &buf);
 
         /* Push a complete packet into the decoder. Useful for UDP and other
          * datagram-oriented protocols.
          */
-        void push_packet(const std::vector<uint8_t> &buf);
+        void push_packet(const Packet &packet);
 
         /* Set the maximum delay in number of AF Packets before we
          * abandon decoding a given pseq.
@@ -113,6 +121,8 @@ class TagDispatcher {
         std::map<std::string, tag_handler> m_handlers;
         std::function<void()> m_af_packet_completed;
         tagpacket_handler m_tagpacket_handler;
+
+        std::vector<std::string> m_ignored_tags;
 };
 
 // Data carried inside the ODRv EDI TAG
diff --git a/lib/edioutput/EDIConfig.h b/lib/edioutput/EDIConfig.h
index 4f1df97..647d77e 100644
--- a/lib/edioutput/EDIConfig.h
+++ b/lib/edioutput/EDIConfig.h
@@ -44,6 +44,7 @@ struct destination_t {
 // Can represent both unicast and multicast destinations
 struct udp_destination_t : public destination_t {
     std::string dest_addr;
+    unsigned int dest_port = 0;
     std::string source_addr;
     unsigned int source_port = 0;
     unsigned int ttl = 10;
@@ -68,10 +69,8 @@ struct configuration_t {
     bool dump          = false;      // dump a file with the EDI packets
     bool verbose       = false;
     bool enable_pft    = false;      // Enable protection and fragmentation
-    bool enable_transport_header = true; // Sets Addr, Source and Dest in PFT
     unsigned int tagpacket_alignment = 0;
     std::vector<std::shared_ptr<destination_t> > destinations;
-    unsigned int dest_port = 0;      // common destination port, because it's encoded in the transport layer
     unsigned int latency_frames = 0; // if nonzero, enable interleaver with a latency of latency_frames * 24ms
 
     bool enabled() const { return destinations.size() > 0; }
diff --git a/lib/edioutput/PFT.cpp b/lib/edioutput/PFT.cpp
index 1e3d4da..b2f07e0 100644
--- a/lib/edioutput/PFT.cpp
+++ b/lib/edioutput/PFT.cpp
@@ -55,7 +55,6 @@ PFT::PFT() { }
 PFT::PFT(const configuration_t &conf) :
     m_k(conf.chunk_len),
     m_m(conf.fec),
-    m_dest_port(conf.dest_port),
     m_pseq(0),
     m_num_chunks(0),
     m_verbose(conf.verbose)
diff --git a/lib/edioutput/PFT.h b/lib/edioutput/PFT.h
index 1019915..4d138c5 100644
--- a/lib/edioutput/PFT.h
+++ b/lib/edioutput/PFT.h
@@ -68,13 +68,14 @@ class PFT
     private:
         unsigned int m_k = 207; // length of RS data word
         unsigned int m_m = 3; // number of fragments that can be recovered if lost
-        unsigned int m_dest_port = 12000; // Destination port for transport header
         uint16_t m_pseq = 0;
         size_t m_num_chunks = 0;
         bool m_verbose = false;
 
-        bool m_transport_header = false;
+        // Transport header is always deactivated
+        const bool m_transport_header = false;
         const uint16_t m_addr_source = 0;
+        const unsigned int m_dest_port = 0;
 };
 
 }
diff --git a/lib/edioutput/TagItems.cpp b/lib/edioutput/TagItems.cpp
index 9746469..739adfa 100644
--- a/lib/edioutput/TagItems.cpp
+++ b/lib/edioutput/TagItems.cpp
@@ -212,8 +212,8 @@ std::vector<uint8_t> TagDSTI::Assemble()
     packet.push_back(0);
     packet.push_back(0);
 
-    uint8_t dfctl = dflc % 250;
-    uint8_t dfcth = dflc / 250;
+    uint8_t dfctl = dlfc % 250;
+    uint8_t dfcth = dlfc / 250;
 
 
     uint16_t dstiHeader = dfctl | (dfcth << 8) | (rfadf << 13) | (atstf << 14) | (stihf << 15);
@@ -254,7 +254,7 @@ std::vector<uint8_t> TagDSTI::Assemble()
     packet[6] = (taglength >> 8) & 0xFF;
     packet[7] = taglength & 0xFF;
 
-    dflc = (dflc+1) % 5000;
+    dlfc = (dlfc+1) % 5000;
 
     /*
     std::cerr << "TagItem dsti, packet.size " << packet.size() << std::endl;
diff --git a/lib/edioutput/TagItems.h b/lib/edioutput/TagItems.h
index 5c81b01..f24dc44 100644
--- a/lib/edioutput/TagItems.h
+++ b/lib/edioutput/TagItems.h
@@ -147,7 +147,7 @@ class TagDSTI : public TagItem
         bool stihf = false;
         bool atstf = false; // presence of atst data
         bool rfadf = false;
-        uint16_t dflc = 0; // modulo 5000 frame counter
+        uint16_t dlfc = 0; // modulo 5000 frame counter
 
         // STI Header (optional)
         uint8_t stat = 0;
diff --git a/lib/edioutput/Transport.cpp b/lib/edioutput/Transport.cpp
index fa7588a..cfed9ec 100644
--- a/lib/edioutput/Transport.cpp
+++ b/lib/edioutput/Transport.cpp
@@ -38,7 +38,7 @@ void configuration_t::print() const
     etiLog.level(info) << " verbose     " << verbose;
     for (auto edi_dest : destinations) {
         if (auto udp_dest = dynamic_pointer_cast<edi::udp_destination_t>(edi_dest)) {
-            etiLog.level(info) << " UDP to " << udp_dest->dest_addr << ":" << dest_port;
+            etiLog.level(info) << " UDP to " << udp_dest->dest_addr << ":" << udp_dest->dest_port;
             if (not udp_dest->source_addr.empty()) {
                 etiLog.level(info) << "  source      " << udp_dest->source_addr;
                 etiLog.level(info) << "  ttl         " << udp_dest->ttl;
@@ -148,7 +148,7 @@ void Sender::write(const TagPacket& tagpacket)
             for (auto& dest : m_conf.destinations) {
                 if (const auto& udp_dest = dynamic_pointer_cast<edi::udp_destination_t>(dest)) {
                     Socket::InetAddress addr;
-                    addr.resolveUdpDestination(udp_dest->dest_addr, m_conf.dest_port);
+                    addr.resolveUdpDestination(udp_dest->dest_addr, udp_dest->dest_port);
 
                     udp_sockets.at(udp_dest.get())->send(edi_frag, addr);
                 }
@@ -176,7 +176,7 @@ void Sender::write(const TagPacket& tagpacket)
         for (auto& dest : m_conf.destinations) {
             if (const auto& udp_dest = dynamic_pointer_cast<edi::udp_destination_t>(dest)) {
                 Socket::InetAddress addr;
-                addr.resolveUdpDestination(udp_dest->dest_addr, m_conf.dest_port);
+                addr.resolveUdpDestination(udp_dest->dest_addr, udp_dest->dest_port);
 
                 if (af_packet.size() > 1400 and not m_udp_fragmentation_warning_printed) {
                     fprintf(stderr, "EDI Output: AF packet larger than 1400,"
diff --git a/lib/zmq.hpp b/lib/zmq.hpp
index eb5416e..74a0574 100644
--- a/lib/zmq.hpp
+++ b/lib/zmq.hpp
@@ -1,4 +1,5 @@
 /*
+    Copyright (c) 2016-2017 ZeroMQ community
     Copyright (c) 2009-2011 250bpm s.r.o.
     Copyright (c) 2011 Botond Ballo
     Copyright (c) 2007-2009 iMatix Corporation
@@ -25,35 +26,130 @@
 #ifndef __ZMQ_HPP_INCLUDED__
 #define __ZMQ_HPP_INCLUDED__
 
+// macros defined if has a specific standard or greater
+#if (defined(__cplusplus) && __cplusplus >= 201103L) || (defined(_MSC_VER) && _MSC_VER >= 1900)
+    #define ZMQ_CPP11
+#endif
+#if (defined(__cplusplus) && __cplusplus >= 201402L) || \
+    (defined(_HAS_CXX14) && _HAS_CXX14 == 1) || \
+    (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // _HAS_CXX14 might not be defined when using C++17 on MSVC
+    #define ZMQ_CPP14
+#endif
+#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1)
+    #define ZMQ_CPP17
+#endif
+
+#if defined(ZMQ_CPP14)
+#define ZMQ_DEPRECATED(msg) [[deprecated(msg)]]
+#elif defined(_MSC_VER)
+#define ZMQ_DEPRECATED(msg) __declspec(deprecated(msg))
+#elif defined(__GNUC__)
+#define ZMQ_DEPRECATED(msg) __attribute__((deprecated(msg)))
+#endif
+
+#if defined(ZMQ_CPP17)
+#define ZMQ_NODISCARD [[nodiscard]]
+#else
+#define ZMQ_NODISCARD
+#endif
+
+#if defined(ZMQ_CPP11)
+#define ZMQ_NOTHROW noexcept
+#define ZMQ_EXPLICIT explicit
+#define ZMQ_OVERRIDE override
+#define ZMQ_NULLPTR nullptr
+#define ZMQ_CONSTEXPR_FN constexpr
+#define ZMQ_CONSTEXPR_VAR constexpr
+#else
+#define ZMQ_NOTHROW throw()
+#define ZMQ_EXPLICIT
+#define ZMQ_OVERRIDE
+#define ZMQ_NULLPTR 0
+#define ZMQ_CONSTEXPR_FN
+#define ZMQ_CONSTEXPR_VAR const
+#endif
+
 #include <zmq.h>
 
-#include <algorithm>
 #include <cassert>
 #include <cstring>
-#include <string>
+
+#include <algorithm>
 #include <exception>
+#include <iomanip>
+#include <sstream>
+#include <string>
+#include <vector>
+#ifdef ZMQ_CPP11
+#include <array>
+#include <chrono>
+#include <tuple>
+#include <memory>
+#endif
+#ifdef ZMQ_CPP17
+#ifdef __has_include
+#if __has_include(<optional>)
+#include <optional>
+#define ZMQ_HAS_OPTIONAL 1
+#endif
+#if __has_include(<string_view>)
+#include <string_view>
+#define ZMQ_HAS_STRING_VIEW 1
+#endif
+#endif
+
+#endif
+
+/*  Version macros for compile-time API version detection                     */
+#define CPPZMQ_VERSION_MAJOR 4
+#define CPPZMQ_VERSION_MINOR 6
+#define CPPZMQ_VERSION_PATCH 0
+
+#define CPPZMQ_VERSION                                                              \
+    ZMQ_MAKE_VERSION(CPPZMQ_VERSION_MAJOR, CPPZMQ_VERSION_MINOR,                    \
+                     CPPZMQ_VERSION_PATCH)
 
 //  Detect whether the compiler supports C++11 rvalue references.
-#if (defined(__GNUC__) && (__GNUC__ > 4 || \
-      (__GNUC__ == 4 && __GNUC_MINOR__ > 2)) && \
-      defined(__GXX_EXPERIMENTAL_CXX0X__))
-    #define ZMQ_HAS_RVALUE_REFS
-    #define ZMQ_DELETED_FUNCTION = delete
+#if (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ > 2))   \
+     && defined(__GXX_EXPERIMENTAL_CXX0X__))
+#define ZMQ_HAS_RVALUE_REFS
+#define ZMQ_DELETED_FUNCTION = delete
 #elif defined(__clang__)
-    #if __has_feature(cxx_rvalue_references)
-        #define ZMQ_HAS_RVALUE_REFS
-    #endif
-
-    #if __has_feature(cxx_deleted_functions)
-        #define ZMQ_DELETED_FUNCTION = delete
-    #else
-        #define ZMQ_DELETED_FUNCTION
-    #endif
+#if __has_feature(cxx_rvalue_references)
+#define ZMQ_HAS_RVALUE_REFS
+#endif
+
+#if __has_feature(cxx_deleted_functions)
+#define ZMQ_DELETED_FUNCTION = delete
+#else
+#define ZMQ_DELETED_FUNCTION
+#endif
+#elif defined(_MSC_VER) && (_MSC_VER >= 1900)
+#define ZMQ_HAS_RVALUE_REFS
+#define ZMQ_DELETED_FUNCTION = delete
 #elif defined(_MSC_VER) && (_MSC_VER >= 1600)
-    #define ZMQ_HAS_RVALUE_REFS
-    #define ZMQ_DELETED_FUNCTION
+#define ZMQ_HAS_RVALUE_REFS
+#define ZMQ_DELETED_FUNCTION
 #else
-    #define ZMQ_DELETED_FUNCTION
+#define ZMQ_DELETED_FUNCTION
+#endif
+
+#if defined(ZMQ_CPP11) && !defined(__llvm__) && !defined(__INTEL_COMPILER) \
+    && defined(__GNUC__) && __GNUC__ < 5
+#define ZMQ_CPP11_PARTIAL
+#elif defined(__GLIBCXX__) && __GLIBCXX__ < 20160805
+//the date here is the last date of gcc 4.9.4, which
+// effectively means libstdc++ from gcc 5.5 and higher won't trigger this branch
+#define ZMQ_CPP11_PARTIAL
+#endif
+
+#ifdef ZMQ_CPP11
+#ifdef ZMQ_CPP11_PARTIAL
+#define ZMQ_IS_TRIVIALLY_COPYABLE(T) __has_trivial_copy(T)
+#else
+#include <type_traits>
+#define ZMQ_IS_TRIVIALLY_COPYABLE(T) std::is_trivially_copyable<T>::value
+#endif
 #endif
 
 #if ZMQ_VERSION >= ZMQ_MAKE_VERSION(3, 3, 0)
@@ -63,540 +159,1962 @@
 #if ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 1, 0)
 #define ZMQ_HAS_PROXY_STEERABLE
 /*  Socket event data  */
-typedef struct {
-    uint16_t event;  // id of the event as bitfield
-    int32_t  value ; // value is either error code, fd or reconnect interval
+typedef struct
+{
+    uint16_t event; // id of the event as bitfield
+    int32_t value;  // value is either error code, fd or reconnect interval
 } zmq_event_t;
 #endif
 
+// Avoid using deprecated message receive function when possible
+#if ZMQ_VERSION < ZMQ_MAKE_VERSION(3, 2, 0)
+#define zmq_msg_recv(msg, socket, flags) zmq_recvmsg(socket, msg, flags)
+#endif
+
+
 // In order to prevent unused variable warnings when building in non-debug
 // mode use this macro to make assertions.
 #ifndef NDEBUG
-#   define ZMQ_ASSERT(expression) assert(expression)
+#define ZMQ_ASSERT(expression) assert(expression)
 #else
-#   define ZMQ_ASSERT(expression) (void)(expression)
+#define ZMQ_ASSERT(expression) (void) (expression)
 #endif
 
 namespace zmq
 {
 
-    typedef zmq_free_fn free_fn;
-    typedef zmq_pollitem_t pollitem_t;
+#ifdef ZMQ_CPP11
+namespace detail
+{
+namespace ranges
+{
+using std::begin;
+using std::end;
+template<class T>
+auto begin(T&& r) -> decltype(begin(std::forward<T>(r)))
+{
+    return begin(std::forward<T>(r));
+}
+template<class T>
+auto end(T&& r) -> decltype(end(std::forward<T>(r)))
+{
+    return end(std::forward<T>(r));
+}
+} // namespace ranges
 
-    class error_t : public std::exception
+template<class T> using void_t = void;
+
+template<class Iter>
+using iter_value_t = typename std::iterator_traits<Iter>::value_type;
+
+template<class Range>
+using range_iter_t = decltype(
+  ranges::begin(std::declval<typename std::remove_reference<Range>::type &>()));
+
+template<class Range>
+using range_value_t = iter_value_t<range_iter_t<Range>>;
+
+template<class T, class = void> struct is_range : std::false_type
+{
+};
+
+template<class T>
+struct is_range<
+  T,
+  void_t<decltype(
+    ranges::begin(std::declval<typename std::remove_reference<T>::type &>())
+    == ranges::end(std::declval<typename std::remove_reference<T>::type &>()))>>
+    : std::true_type
+{
+};
+
+} // namespace detail
+#endif
+
+typedef zmq_free_fn free_fn;
+typedef zmq_pollitem_t pollitem_t;
+
+class error_t : public std::exception
+{
+  public:
+    error_t() : errnum(zmq_errno()) {}
+    virtual const char *what() const ZMQ_NOTHROW ZMQ_OVERRIDE { return zmq_strerror(errnum); }
+    int num() const { return errnum; }
+
+  private:
+    int errnum;
+};
+
+inline int poll(zmq_pollitem_t *items_, size_t nitems_, long timeout_ = -1)
+{
+    int rc = zmq_poll(items_, static_cast<int>(nitems_), timeout_);
+    if (rc < 0)
+        throw error_t();
+    return rc;
+}
+
+ZMQ_DEPRECATED("from 4.3.1, use poll taking non-const items")
+inline int poll(zmq_pollitem_t const *items_, size_t nitems_, long timeout_ = -1)
+{
+    return poll(const_cast<zmq_pollitem_t *>(items_), nitems_, timeout_);
+}
+
+#ifdef ZMQ_CPP11
+ZMQ_DEPRECATED("from 4.3.1, use poll taking non-const items")
+inline int
+poll(zmq_pollitem_t const *items, size_t nitems, std::chrono::milliseconds timeout)
+{
+    return poll(const_cast<zmq_pollitem_t *>(items), nitems, static_cast<long>(timeout.count()));
+}
+
+ZMQ_DEPRECATED("from 4.3.1, use poll taking non-const items")
+inline int poll(std::vector<zmq_pollitem_t> const &items,
+                std::chrono::milliseconds timeout)
+{
+    return poll(const_cast<zmq_pollitem_t *>(items.data()), items.size(), static_cast<long>(timeout.count()));
+}
+
+ZMQ_DEPRECATED("from 4.3.1, use poll taking non-const items")
+inline int poll(std::vector<zmq_pollitem_t> const &items, long timeout_ = -1)
+{
+    return poll(const_cast<zmq_pollitem_t *>(items.data()), items.size(), timeout_);
+}
+
+inline int
+poll(zmq_pollitem_t *items, size_t nitems, std::chrono::milliseconds timeout)
+{
+    return poll(items, nitems, static_cast<long>(timeout.count()));
+}
+
+inline int poll(std::vector<zmq_pollitem_t> &items,
+                std::chrono::milliseconds timeout)
+{
+    return poll(items.data(), items.size(), static_cast<long>(timeout.count()));
+}
+
+inline int poll(std::vector<zmq_pollitem_t> &items, long timeout_ = -1)
+{
+    return poll(items.data(), items.size(), timeout_);
+}
+#endif
+
+
+inline void version(int *major_, int *minor_, int *patch_)
+{
+    zmq_version(major_, minor_, patch_);
+}
+
+#ifdef ZMQ_CPP11
+inline std::tuple<int, int, int> version()
+{
+    std::tuple<int, int, int> v;
+    zmq_version(&std::get<0>(v), &std::get<1>(v), &std::get<2>(v));
+    return v;
+}
+#endif
+
+class message_t
+{
+  public:
+    message_t() ZMQ_NOTHROW
     {
-    public:
+        int rc = zmq_msg_init(&msg);
+        ZMQ_ASSERT(rc == 0);
+    }
 
-        error_t () : errnum (zmq_errno ()) {}
+    explicit message_t(size_t size_)
+    {
+        int rc = zmq_msg_init_size(&msg, size_);
+        if (rc != 0)
+            throw error_t();
+    }
 
-        virtual const char *what () const throw ()
-        {
-            return zmq_strerror (errnum);
-        }
+    template<class ForwardIter> message_t(ForwardIter first, ForwardIter last)
+    {
+        typedef typename std::iterator_traits<ForwardIter>::value_type value_t;
 
-        int num () const
-        {
-            return errnum;
-        }
+        assert(std::distance(first, last) >= 0);
+        size_t const size_ =
+          static_cast<size_t>(std::distance(first, last)) * sizeof(value_t);
+        int const rc = zmq_msg_init_size(&msg, size_);
+        if (rc != 0)
+            throw error_t();
+        std::copy(first, last, data<value_t>());
+    }
 
-    private:
+    message_t(const void *data_, size_t size_)
+    {
+        int rc = zmq_msg_init_size(&msg, size_);
+        if (rc != 0)
+            throw error_t();
+        memcpy(data(), data_, size_);
+    }
 
-        int errnum;
-    };
+    message_t(void *data_, size_t size_, free_fn *ffn_, void *hint_ = ZMQ_NULLPTR)
+    {
+        int rc = zmq_msg_init_data(&msg, data_, size_, ffn_, hint_);
+        if (rc != 0)
+            throw error_t();
+    }
 
-    inline int poll (zmq_pollitem_t *items_, int nitems_, long timeout_ = -1)
+#if defined(ZMQ_CPP11) && !defined(ZMQ_CPP11_PARTIAL)
+    template<class Range,
+             typename = typename std::enable_if<
+               detail::is_range<Range>::value
+               && ZMQ_IS_TRIVIALLY_COPYABLE(detail::range_value_t<Range>)
+               && !std::is_same<Range, message_t>::value>::type>
+    explicit message_t(const Range &rng) :
+        message_t(detail::ranges::begin(rng), detail::ranges::end(rng))
     {
-        int rc = zmq_poll (items_, nitems_, timeout_);
-        if (rc < 0)
-            throw error_t ();
-        return rc;
     }
+#endif
 
-    inline void proxy (void *frontend, void *backend, void *capture)
+#ifdef ZMQ_HAS_RVALUE_REFS
+    message_t(message_t &&rhs) ZMQ_NOTHROW : msg(rhs.msg)
     {
-        int rc = zmq_proxy (frontend, backend, capture);
+        int rc = zmq_msg_init(&rhs.msg);
+        ZMQ_ASSERT(rc == 0);
+    }
+
+    message_t &operator=(message_t &&rhs) ZMQ_NOTHROW
+    {
+        std::swap(msg, rhs.msg);
+        return *this;
+    }
+#endif
+
+    ~message_t() ZMQ_NOTHROW
+    {
+        int rc = zmq_msg_close(&msg);
+        ZMQ_ASSERT(rc == 0);
+    }
+
+    void rebuild()
+    {
+        int rc = zmq_msg_close(&msg);
         if (rc != 0)
-            throw error_t ();
+            throw error_t();
+        rc = zmq_msg_init(&msg);
+        ZMQ_ASSERT(rc == 0);
     }
-    
-#ifdef ZMQ_HAS_PROXY_STEERABLE
-    inline void proxy_steerable (void *frontend, void *backend, void *capture, void *control)
+
+    void rebuild(size_t size_)
+    {
+        int rc = zmq_msg_close(&msg);
+        if (rc != 0)
+            throw error_t();
+        rc = zmq_msg_init_size(&msg, size_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    void rebuild(const void *data_, size_t size_)
+    {
+        int rc = zmq_msg_close(&msg);
+        if (rc != 0)
+            throw error_t();
+        rc = zmq_msg_init_size(&msg, size_);
+        if (rc != 0)
+            throw error_t();
+        memcpy(data(), data_, size_);
+    }
+
+    void rebuild(void *data_, size_t size_, free_fn *ffn_, void *hint_ = ZMQ_NULLPTR)
+    {
+        int rc = zmq_msg_close(&msg);
+        if (rc != 0)
+            throw error_t();
+        rc = zmq_msg_init_data(&msg, data_, size_, ffn_, hint_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    ZMQ_DEPRECATED("from 4.3.1, use move taking non-const reference instead")
+    void move(message_t const *msg_)
+    {
+        int rc = zmq_msg_move(&msg, const_cast<zmq_msg_t *>(msg_->handle()));
+        if (rc != 0)
+            throw error_t();
+    }
+
+    void move(message_t &msg_)
+    {
+        int rc = zmq_msg_move(&msg, msg_.handle());
+        if (rc != 0)
+            throw error_t();
+    }
+
+    ZMQ_DEPRECATED("from 4.3.1, use copy taking non-const reference instead")
+    void copy(message_t const *msg_)
+    {
+        int rc = zmq_msg_copy(&msg, const_cast<zmq_msg_t *>(msg_->handle()));
+        if (rc != 0)
+            throw error_t();
+    }
+
+    void copy(message_t &msg_)
     {
-        int rc = zmq_proxy_steerable (frontend, backend, capture, control);
+        int rc = zmq_msg_copy(&msg, msg_.handle());
         if (rc != 0)
-            throw error_t ();
+            throw error_t();
+    }
+
+    bool more() const ZMQ_NOTHROW
+    {
+        int rc = zmq_msg_more(const_cast<zmq_msg_t *>(&msg));
+        return rc != 0;
+    }
+
+    void *data() ZMQ_NOTHROW { return zmq_msg_data(&msg); }
+
+    const void *data() const ZMQ_NOTHROW
+    {
+        return zmq_msg_data(const_cast<zmq_msg_t *>(&msg));
+    }
+
+    size_t size() const ZMQ_NOTHROW
+    {
+        return zmq_msg_size(const_cast<zmq_msg_t *>(&msg));
+    }
+
+    ZMQ_NODISCARD bool empty() const ZMQ_NOTHROW
+    {
+        return size() == 0u;
+    }
+
+    template<typename T> T *data() ZMQ_NOTHROW { return static_cast<T *>(data()); }
+
+    template<typename T> T const *data() const ZMQ_NOTHROW
+    {
+        return static_cast<T const *>(data());
+    }
+
+    ZMQ_DEPRECATED("from 4.3.0, use operator== instead")
+    bool equal(const message_t *other) const ZMQ_NOTHROW
+    {
+        return *this == *other;
+    }
+
+    bool operator==(const message_t &other) const ZMQ_NOTHROW
+    {
+        const size_t my_size = size();
+        return my_size == other.size() && 0 == memcmp(data(), other.data(), my_size);
+    }
+
+    bool operator!=(const message_t &other) const ZMQ_NOTHROW
+    {
+        return !(*this == other);
+    }
+
+#if ZMQ_VERSION >= ZMQ_MAKE_VERSION(3, 2, 0)
+    int get(int property_)
+    {
+        int value = zmq_msg_get(&msg, property_);
+        if (value == -1)
+            throw error_t();
+        return value;
     }
 #endif
-    
-    inline void version (int *major_, int *minor_, int *patch_)
+
+#if ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 1, 0)
+    const char *gets(const char *property_)
     {
-        zmq_version (major_, minor_, patch_);
+        const char *value = zmq_msg_gets(&msg, property_);
+        if (value == ZMQ_NULLPTR)
+            throw error_t();
+        return value;
     }
+#endif
 
-    class message_t
+#if defined(ZMQ_BUILD_DRAFT_API) && ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 0)
+    uint32_t routing_id() const
     {
-        friend class socket_t;
+        return zmq_msg_routing_id(const_cast<zmq_msg_t*>(&msg));
+    }
 
-    public:
+    void set_routing_id(uint32_t routing_id)
+    {
+        int rc = zmq_msg_set_routing_id(&msg, routing_id);
+        if (rc != 0)
+            throw error_t();
+    }
 
-        inline message_t ()
-        {
-            int rc = zmq_msg_init (&msg);
-            if (rc != 0)
-                throw error_t ();
-        }
+    const char* group() const
+    {
+        return zmq_msg_group(const_cast<zmq_msg_t*>(&msg));
+    }
 
-        inline explicit message_t (size_t size_)
-        {
-            int rc = zmq_msg_init_size (&msg, size_);
-            if (rc != 0)
-                throw error_t ();
-        }
+    void set_group(const char* group)
+    {
+        int rc = zmq_msg_set_group(&msg, group);
+        if (rc != 0)
+            throw error_t();
+    }
+#endif
 
-        inline message_t (void *data_, size_t size_, free_fn *ffn_,
-            void *hint_ = NULL)
-        {
-            int rc = zmq_msg_init_data (&msg, data_, size_, ffn_, hint_);
-            if (rc != 0)
-                throw error_t ();
+    // interpret message content as a string
+    std::string to_string() const
+    {
+        return std::string(static_cast<const char*>(data()), size());
+    }
+#ifdef ZMQ_CPP17
+    // interpret message content as a string
+    std::string_view to_string_view() const noexcept
+    {
+        return std::string_view(static_cast<const char*>(data()), size());
+    }
+#endif
+
+    /** Dump content to string for debugging.
+    *   Ascii chars are readable, the rest is printed as hex.
+    *   Probably ridiculously slow.
+    *   Use to_string() or to_string_view() for
+    *   interpreting the message as a string.
+    */
+    std::string str() const
+    {
+        // Partly mutuated from the same method in zmq::multipart_t
+        std::stringstream os;
+
+        const unsigned char *msg_data = this->data<unsigned char>();
+        unsigned char byte;
+        size_t size = this->size();
+        int is_ascii[2] = {0, 0};
+
+        os << "zmq::message_t [size " << std::dec << std::setw(3)
+           << std::setfill('0') << size << "] (";
+        // Totally arbitrary
+        if (size >= 1000) {
+            os << "... too big to print)";
+        } else {
+            while (size--) {
+                byte = *msg_data++;
+
+                is_ascii[1] = (byte >= 32 && byte < 127);
+                if (is_ascii[1] != is_ascii[0])
+                    os << " "; // Separate text/non text
+
+                if (is_ascii[1]) {
+                    os << byte;
+                } else {
+                    os << std::hex << std::uppercase << std::setw(2)
+                       << std::setfill('0') << static_cast<short>(byte);
+                }
+                is_ascii[0] = is_ascii[1];
+            }
+            os << ")";
         }
+        return os.str();
+    }
+
+    void swap(message_t &other) ZMQ_NOTHROW
+    {
+        // this assumes zmq::msg_t from libzmq is trivially relocatable
+        std::swap(msg, other.msg);
+    }
+
+    ZMQ_NODISCARD zmq_msg_t *handle() ZMQ_NOTHROW { return &msg; }
+    ZMQ_NODISCARD const zmq_msg_t *handle() const ZMQ_NOTHROW { return &msg; }
+
+  private:
+    //  The underlying message
+    zmq_msg_t msg;
+
+    //  Disable implicit message copying, so that users won't use shared
+    //  messages (less efficient) without being aware of the fact.
+    message_t(const message_t &) ZMQ_DELETED_FUNCTION;
+    void operator=(const message_t &) ZMQ_DELETED_FUNCTION;
+};
+
+inline void swap(message_t &a, message_t &b) ZMQ_NOTHROW
+{
+    a.swap(b);
+}
+
+class context_t
+{
+  public:
+    context_t()
+    {
+        ptr = zmq_ctx_new();
+        if (ptr == ZMQ_NULLPTR)
+            throw error_t();
+    }
+
+
+    explicit context_t(int io_threads_,
+                              int max_sockets_ = ZMQ_MAX_SOCKETS_DFLT)
+    {
+        ptr = zmq_ctx_new();
+        if (ptr == ZMQ_NULLPTR)
+            throw error_t();
+
+        int rc = zmq_ctx_set(ptr, ZMQ_IO_THREADS, io_threads_);
+        ZMQ_ASSERT(rc == 0);
+
+        rc = zmq_ctx_set(ptr, ZMQ_MAX_SOCKETS, max_sockets_);
+        ZMQ_ASSERT(rc == 0);
+    }
 
 #ifdef ZMQ_HAS_RVALUE_REFS
-        inline message_t (message_t &&rhs) : msg (rhs.msg)
-        {
-            int rc = zmq_msg_init (&rhs.msg);
-            if (rc != 0)
-                throw error_t ();
-        }
+    context_t(context_t &&rhs) ZMQ_NOTHROW : ptr(rhs.ptr) { rhs.ptr = ZMQ_NULLPTR; }
+    context_t &operator=(context_t &&rhs) ZMQ_NOTHROW
+    {
+        close();
+        std::swap(ptr, rhs.ptr);
+        return *this;
+    }
+#endif
+
+    int setctxopt(int option_, int optval_)
+    {
+        int rc = zmq_ctx_set(ptr, option_, optval_);
+        ZMQ_ASSERT(rc == 0);
+        return rc;
+    }
+
+    int getctxopt(int option_) { return zmq_ctx_get(ptr, option_); }
+
+    ~context_t() ZMQ_NOTHROW { close(); }
+
+    void close() ZMQ_NOTHROW
+    {
+        if (ptr == ZMQ_NULLPTR)
+            return;
+
+        int rc;
+        do {
+            rc = zmq_ctx_destroy(ptr);
+        } while (rc == -1 && errno == EINTR);
+
+        ZMQ_ASSERT(rc == 0);
+        ptr = ZMQ_NULLPTR;
+    }
+
+    //  Be careful with this, it's probably only useful for
+    //  using the C api together with an existing C++ api.
+    //  Normally you should never need to use this.
+    ZMQ_EXPLICIT operator void *() ZMQ_NOTHROW { return ptr; }
+
+    ZMQ_EXPLICIT operator void const *() const ZMQ_NOTHROW { return ptr; }
+
+    operator bool() const ZMQ_NOTHROW { return ptr != ZMQ_NULLPTR; }
+
+    void swap(context_t &other) ZMQ_NOTHROW
+    {
+        std::swap(ptr, other.ptr);
+    }
+
+  private:
+    void *ptr;
+
+    context_t(const context_t &) ZMQ_DELETED_FUNCTION;
+    void operator=(const context_t &) ZMQ_DELETED_FUNCTION;
+};
+
+inline void swap(context_t &a, context_t &b) ZMQ_NOTHROW {
+    a.swap(b);
+}
+
+#ifdef ZMQ_CPP11
+
+struct recv_buffer_size
+{
+    size_t size;    // number of bytes written to buffer
+    size_t untruncated_size;  // untruncated message size in bytes
+
+    ZMQ_NODISCARD bool truncated() const noexcept
+    {
+        return size != untruncated_size;
+    }
+};
+
+#if defined(ZMQ_HAS_OPTIONAL) && (ZMQ_HAS_OPTIONAL > 0)
+
+using send_result_t = std::optional<size_t>;
+using recv_result_t = std::optional<size_t>;
+using recv_buffer_result_t = std::optional<recv_buffer_size>;
+
+#else
+
+namespace detail
+{
+// A C++11 type emulating the most basic
+// operations of std::optional for trivial types
+template<class T> class trivial_optional
+{
+  public:
+    static_assert(std::is_trivial<T>::value, "T must be trivial");
+    using value_type = T;
+
+    trivial_optional() = default;
+    trivial_optional(T value) noexcept : _value(value), _has_value(true) {}
+
+    const T *operator->() const noexcept
+    {
+        assert(_has_value);
+        return &_value;
+    }
+    T *operator->() noexcept
+    {
+        assert(_has_value);
+        return &_value;
+    }
+
+    const T &operator*() const noexcept
+    {
+        assert(_has_value);
+        return _value;
+    }
+    T &operator*() noexcept
+    {
+        assert(_has_value);
+        return _value;
+    }
+
+    T &value()
+    {
+        if (!_has_value)
+            throw std::exception();
+        return _value;
+    }
+    const T &value() const
+    {
+        if (!_has_value)
+            throw std::exception();
+        return _value;
+    }
+
+    explicit operator bool() const noexcept { return _has_value; }
+    bool has_value() const noexcept { return _has_value; }
+
+  private:
+    T _value{};
+    bool _has_value{false};
+};
+} // namespace detail
+
+using send_result_t = detail::trivial_optional<size_t>;
+using recv_result_t = detail::trivial_optional<size_t>;
+using recv_buffer_result_t = detail::trivial_optional<recv_buffer_size>;
 
-        inline message_t &operator = (message_t &&rhs)
-        {
-            std::swap (msg, rhs.msg);
-            return *this;
-        }
 #endif
 
-        inline ~message_t ()
-        {
-            int rc = zmq_msg_close (&msg);
-            ZMQ_ASSERT (rc == 0);
-        }
+namespace detail
+{
 
-        inline void rebuild ()
-        {
-            int rc = zmq_msg_close (&msg);
-            if (rc != 0)
-                throw error_t ();
-            rc = zmq_msg_init (&msg);
-            if (rc != 0)
-                throw error_t ();
-        }
+template<class T>
+constexpr T enum_bit_or(T a, T b) noexcept
+{
+    static_assert(std::is_enum<T>::value, "must be enum");
+    using U = typename std::underlying_type<T>::type;
+    return static_cast<T>(static_cast<U>(a) | static_cast<U>(b));
+}
+template<class T>
+constexpr T enum_bit_and(T a, T b) noexcept
+{
+    static_assert(std::is_enum<T>::value, "must be enum");
+    using U = typename std::underlying_type<T>::type;
+    return static_cast<T>(static_cast<U>(a) & static_cast<U>(b));
+}
+template<class T>
+constexpr T enum_bit_xor(T a, T b) noexcept
+{
+    static_assert(std::is_enum<T>::value, "must be enum");
+    using U = typename std::underlying_type<T>::type;
+    return static_cast<T>(static_cast<U>(a) ^ static_cast<U>(b));
+}
+template<class T>
+constexpr T enum_bit_not(T a) noexcept
+{
+    static_assert(std::is_enum<T>::value, "must be enum");
+    using U = typename std::underlying_type<T>::type;
+    return static_cast<T>(~static_cast<U>(a));
+}
+} // namespace detail
 
-        inline void rebuild (size_t size_)
-        {
-            int rc = zmq_msg_close (&msg);
-            if (rc != 0)
-                throw error_t ();
-            rc = zmq_msg_init_size (&msg, size_);
-            if (rc != 0)
-                throw error_t ();
-        }
+// partially satisfies named requirement BitmaskType
+enum class send_flags : int
+{
+    none = 0,
+    dontwait = ZMQ_DONTWAIT,
+    sndmore = ZMQ_SNDMORE
+};
 
-        inline void rebuild (void *data_, size_t size_, free_fn *ffn_,
-            void *hint_ = NULL)
-        {
-            int rc = zmq_msg_close (&msg);
-            if (rc != 0)
-                throw error_t ();
-            rc = zmq_msg_init_data (&msg, data_, size_, ffn_, hint_);
-            if (rc != 0)
-                throw error_t ();
-        }
+constexpr send_flags operator|(send_flags a, send_flags b) noexcept
+{
+    return detail::enum_bit_or(a, b);
+}
+constexpr send_flags operator&(send_flags a, send_flags b) noexcept
+{
+    return detail::enum_bit_and(a, b);
+}
+constexpr send_flags operator^(send_flags a, send_flags b) noexcept
+{
+    return detail::enum_bit_xor(a, b);
+}
+constexpr send_flags operator~(send_flags a) noexcept
+{
+    return detail::enum_bit_not(a);
+}
 
-        inline void move (message_t *msg_)
-        {
-            int rc = zmq_msg_move (&msg, &(msg_->msg));
-            if (rc != 0)
-                throw error_t ();
-        }
+// partially satisfies named requirement BitmaskType
+enum class recv_flags : int
+{
+    none = 0,
+    dontwait = ZMQ_DONTWAIT
+};
 
-        inline void copy (message_t *msg_)
-        {
-            int rc = zmq_msg_copy (&msg, &(msg_->msg));
-            if (rc != 0)
-                throw error_t ();
-        }
+constexpr recv_flags operator|(recv_flags a, recv_flags b) noexcept
+{
+    return detail::enum_bit_or(a, b);
+}
+constexpr recv_flags operator&(recv_flags a, recv_flags b) noexcept
+{
+    return detail::enum_bit_and(a, b);
+}
+constexpr recv_flags operator^(recv_flags a, recv_flags b) noexcept
+{
+    return detail::enum_bit_xor(a, b);
+}
+constexpr recv_flags operator~(recv_flags a) noexcept
+{
+    return detail::enum_bit_not(a);
+}
 
-        inline bool more ()
-        {
-            int rc = zmq_msg_more (&msg);
-            return rc != 0;
-        }
 
-        inline void *data ()
-        {
-            return zmq_msg_data (&msg);
-        }
+// mutable_buffer, const_buffer and buffer are based on
+// the Networking TS specification, draft:
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/n4771.pdf
 
-        inline const void* data () const
-        {
-            return zmq_msg_data (const_cast<zmq_msg_t*>(&msg));
-        }
+class mutable_buffer
+{
+  public:
+    constexpr mutable_buffer() noexcept : _data(nullptr), _size(0) {}
+    constexpr mutable_buffer(void *p, size_t n) noexcept : _data(p), _size(n)
+    {
+#ifdef ZMQ_CPP14
+        assert(p != nullptr || n == 0);
+#endif
+    }
 
-        inline size_t size () const
-        {
-            return zmq_msg_size (const_cast<zmq_msg_t*>(&msg));
-        }
+    constexpr void *data() const noexcept { return _data; }
+    constexpr size_t size() const noexcept { return _size; }
+    mutable_buffer &operator+=(size_t n) noexcept
+    {
+        // (std::min) is a workaround for when a min macro is defined
+        const auto shift = (std::min)(n, _size);
+        _data = static_cast<char *>(_data) + shift;
+        _size -= shift;
+        return *this;
+    }
 
-    private:
+  private:
+    void *_data;
+    size_t _size;
+};
 
-        //  The underlying message
-        zmq_msg_t msg;
+inline mutable_buffer operator+(const mutable_buffer &mb, size_t n) noexcept
+{
+    return mutable_buffer(static_cast<char *>(mb.data()) + (std::min)(n, mb.size()),
+                          mb.size() - (std::min)(n, mb.size()));
+}
+inline mutable_buffer operator+(size_t n, const mutable_buffer &mb) noexcept
+{
+    return mb + n;
+}
 
-        //  Disable implicit message copying, so that users won't use shared
-        //  messages (less efficient) without being aware of the fact.
-        message_t (const message_t&);
-        void operator = (const message_t&);
-    };
+class const_buffer
+{
+  public:
+    constexpr const_buffer() noexcept : _data(nullptr), _size(0) {}
+    constexpr const_buffer(const void *p, size_t n) noexcept : _data(p), _size(n)
+    {
+#ifdef ZMQ_CPP14
+        assert(p != nullptr || n == 0);
+#endif
+    }
+    constexpr const_buffer(const mutable_buffer &mb) noexcept :
+        _data(mb.data()),
+        _size(mb.size())
+    {
+    }
 
-    class context_t
+    constexpr const void *data() const noexcept { return _data; }
+    constexpr size_t size() const noexcept { return _size; }
+    const_buffer &operator+=(size_t n) noexcept
     {
-        friend class socket_t;
+        const auto shift = (std::min)(n, _size);
+        _data = static_cast<const char *>(_data) + shift;
+        _size -= shift;
+        return *this;
+    }
 
-    public:
-        inline context_t ()
-        {
-            ptr = zmq_ctx_new ();
-            if (ptr == NULL)
-                throw error_t ();
-        }
+  private:
+    const void *_data;
+    size_t _size;
+};
 
+inline const_buffer operator+(const const_buffer &cb, size_t n) noexcept
+{
+    return const_buffer(static_cast<const char *>(cb.data())
+                          + (std::min)(n, cb.size()),
+                        cb.size() - (std::min)(n, cb.size()));
+}
+inline const_buffer operator+(size_t n, const const_buffer &cb) noexcept
+{
+    return cb + n;
+}
 
-        inline explicit context_t (int io_threads_, int max_sockets_ = ZMQ_MAX_SOCKETS_DFLT)
-        {
-            ptr = zmq_ctx_new ();
-            if (ptr == NULL)
-                throw error_t ();
+// buffer creation
 
-            int rc = zmq_ctx_set (ptr, ZMQ_IO_THREADS, io_threads_);
-            ZMQ_ASSERT (rc == 0);
+constexpr mutable_buffer buffer(void* p, size_t n) noexcept
+{
+    return mutable_buffer(p, n);
+}
+constexpr const_buffer buffer(const void* p, size_t n) noexcept
+{
+    return const_buffer(p, n);
+}
+constexpr mutable_buffer buffer(const mutable_buffer& mb) noexcept
+{
+    return mb;
+}
+inline mutable_buffer buffer(const mutable_buffer& mb, size_t n) noexcept
+{
+    return mutable_buffer(mb.data(), (std::min)(mb.size(), n));
+}
+constexpr const_buffer buffer(const const_buffer& cb) noexcept
+{
+    return cb;
+}
+inline const_buffer buffer(const const_buffer& cb, size_t n) noexcept
+{
+    return const_buffer(cb.data(), (std::min)(cb.size(), n));
+}
 
-            rc = zmq_ctx_set (ptr, ZMQ_MAX_SOCKETS, max_sockets_);
-            ZMQ_ASSERT (rc == 0);
-        }
+namespace detail
+{
+
+template<class T>
+struct is_buffer
+{
+    static constexpr bool value = 
+        std::is_same<T, const_buffer>::value ||
+        std::is_same<T, mutable_buffer>::value;
+};
+
+template<class T> struct is_pod_like
+{
+    // NOTE: The networking draft N4771 section 16.11 requires
+    // T in the buffer functions below to be
+    // trivially copyable OR standard layout.
+    // Here we decide to be conservative and require both.
+    static constexpr bool value =
+      ZMQ_IS_TRIVIALLY_COPYABLE(T) && std::is_standard_layout<T>::value;
+};
+
+template<class C> constexpr auto seq_size(const C &c) noexcept -> decltype(c.size())
+{
+    return c.size();
+}
+template<class T, size_t N>
+constexpr size_t seq_size(const T (&/*array*/)[N]) noexcept
+{
+    return N;
+}
+
+template<class Seq>
+auto buffer_contiguous_sequence(Seq &&seq) noexcept
+  -> decltype(buffer(std::addressof(*std::begin(seq)), size_t{}))
+{
+    using T = typename std::remove_cv<
+      typename std::remove_reference<decltype(*std::begin(seq))>::type>::type;
+    static_assert(detail::is_pod_like<T>::value, "T must be POD");
+
+    const auto size = seq_size(seq);
+    return buffer(size != 0u ? std::addressof(*std::begin(seq)) : nullptr,
+                  size * sizeof(T));
+}
+template<class Seq>
+auto buffer_contiguous_sequence(Seq &&seq, size_t n_bytes) noexcept
+  -> decltype(buffer_contiguous_sequence(seq))
+{
+    using T = typename std::remove_cv<
+      typename std::remove_reference<decltype(*std::begin(seq))>::type>::type;
+    static_assert(detail::is_pod_like<T>::value, "T must be POD");
+
+    const auto size = seq_size(seq);
+    return buffer(size != 0u ? std::addressof(*std::begin(seq)) : nullptr,
+                  (std::min)(size * sizeof(T), n_bytes));
+}
+
+} // namespace detail
+
+// C array
+template<class T, size_t N> mutable_buffer buffer(T (&data)[N]) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, size_t N>
+mutable_buffer buffer(T (&data)[N], size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+template<class T, size_t N> const_buffer buffer(const T (&data)[N]) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, size_t N>
+const_buffer buffer(const T (&data)[N], size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+// std::array
+template<class T, size_t N> mutable_buffer buffer(std::array<T, N> &data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, size_t N>
+mutable_buffer buffer(std::array<T, N> &data, size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+template<class T, size_t N>
+const_buffer buffer(std::array<const T, N> &data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, size_t N>
+const_buffer buffer(std::array<const T, N> &data, size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+template<class T, size_t N>
+const_buffer buffer(const std::array<T, N> &data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, size_t N>
+const_buffer buffer(const std::array<T, N> &data, size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+// std::vector
+template<class T, class Allocator>
+mutable_buffer buffer(std::vector<T, Allocator> &data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, class Allocator>
+mutable_buffer buffer(std::vector<T, Allocator> &data, size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+template<class T, class Allocator>
+const_buffer buffer(const std::vector<T, Allocator> &data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, class Allocator>
+const_buffer buffer(const std::vector<T, Allocator> &data, size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+// std::basic_string
+template<class T, class Traits, class Allocator>
+mutable_buffer buffer(std::basic_string<T, Traits, Allocator> &data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, class Traits, class Allocator>
+mutable_buffer buffer(std::basic_string<T, Traits, Allocator> &data,
+                      size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+template<class T, class Traits, class Allocator>
+const_buffer buffer(const std::basic_string<T, Traits, Allocator> &data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, class Traits, class Allocator>
+const_buffer buffer(const std::basic_string<T, Traits, Allocator> &data,
+                    size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+
+#if defined(ZMQ_HAS_STRING_VIEW) && (ZMQ_HAS_STRING_VIEW > 0)
+// std::basic_string_view
+template<class T, class Traits>
+const_buffer buffer(std::basic_string_view<T, Traits> data) noexcept
+{
+    return detail::buffer_contiguous_sequence(data);
+}
+template<class T, class Traits>
+const_buffer buffer(std::basic_string_view<T, Traits> data, size_t n_bytes) noexcept
+{
+    return detail::buffer_contiguous_sequence(data, n_bytes);
+}
+#endif
+
+// Buffer for a string literal (null terminated)
+// where the buffer size excludes the terminating character.
+// Equivalent to zmq::buffer(std::string_view("...")).
+template<class Char, size_t N>
+constexpr const_buffer str_buffer(const Char (&data)[N]) noexcept
+{
+    static_assert(detail::is_pod_like<Char>::value, "Char must be POD");
+#ifdef ZMQ_CPP14
+    assert(data[N - 1] == Char{0});
+#endif
+    return const_buffer(static_cast<const Char*>(data),
+                        (N - 1) * sizeof(Char));
+}
+
+namespace literals
+{
+    constexpr const_buffer operator"" _zbuf(const char* str, size_t len) noexcept
+    {
+        return const_buffer(str, len * sizeof(char));
+    }
+    constexpr const_buffer operator"" _zbuf(const wchar_t* str, size_t len) noexcept
+    {
+        return const_buffer(str, len * sizeof(wchar_t));
+    }
+    constexpr const_buffer operator"" _zbuf(const char16_t* str, size_t len) noexcept
+    {
+        return const_buffer(str, len * sizeof(char16_t));
+    }
+    constexpr const_buffer operator"" _zbuf(const char32_t* str, size_t len) noexcept
+    {
+        return const_buffer(str, len * sizeof(char32_t));
+    }
+}
+
+#endif // ZMQ_CPP11
+
+namespace detail
+{
+
+class socket_base
+{
+public:
+    socket_base() ZMQ_NOTHROW : _handle(ZMQ_NULLPTR) {}
+    ZMQ_EXPLICIT socket_base(void *handle) ZMQ_NOTHROW : _handle(handle) {}
+
+    template<typename T> void setsockopt(int option_, T const &optval)
+    {
+        setsockopt(option_, &optval, sizeof(T));
+    }
+
+    void setsockopt(int option_, const void *optval_, size_t optvallen_)
+    {
+        int rc = zmq_setsockopt(_handle, option_, optval_, optvallen_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    void getsockopt(int option_, void *optval_, size_t *optvallen_) const
+    {
+        int rc = zmq_getsockopt(_handle, option_, optval_, optvallen_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    template<typename T> T getsockopt(int option_) const
+    {
+        T optval;
+        size_t optlen = sizeof(T);
+        getsockopt(option_, &optval, &optlen);
+        return optval;
+    }
+
+    void bind(std::string const &addr) { bind(addr.c_str()); }
+
+    void bind(const char *addr_)
+    {
+        int rc = zmq_bind(_handle, addr_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    void unbind(std::string const &addr) { unbind(addr.c_str()); }
+
+    void unbind(const char *addr_)
+    {
+        int rc = zmq_unbind(_handle, addr_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    void connect(std::string const &addr) { connect(addr.c_str()); }
+
+    void connect(const char *addr_)
+    {
+        int rc = zmq_connect(_handle, addr_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    void disconnect(std::string const &addr) { disconnect(addr.c_str()); }
+
+    void disconnect(const char *addr_)
+    {
+        int rc = zmq_disconnect(_handle, addr_);
+        if (rc != 0)
+            throw error_t();
+    }
+
+    bool connected() const ZMQ_NOTHROW { return (_handle != ZMQ_NULLPTR); }
+
+#ifdef ZMQ_CPP11
+    ZMQ_DEPRECATED("from 4.3.1, use send taking a const_buffer and send_flags")
+#endif
+    size_t send(const void *buf_, size_t len_, int flags_ = 0)
+    {
+        int nbytes = zmq_send(_handle, buf_, len_, flags_);
+        if (nbytes >= 0)
+            return static_cast<size_t>(nbytes);
+        if (zmq_errno() == EAGAIN)
+            return 0;
+        throw error_t();
+    }
+
+#ifdef ZMQ_CPP11
+    ZMQ_DEPRECATED("from 4.3.1, use send taking message_t and send_flags")
+#endif
+    bool send(message_t &msg_,
+              int flags_ = 0) // default until removed
+    {
+        int nbytes = zmq_msg_send(msg_.handle(), _handle, flags_);
+        if (nbytes >= 0)
+            return true;
+        if (zmq_errno() == EAGAIN)
+            return false;
+        throw error_t();
+    }
+
+    template<typename T>
+#ifdef ZMQ_CPP11
+    ZMQ_DEPRECATED("from 4.4.1, use send taking message_t or buffer (for contiguous ranges), and send_flags")
+#endif
+    bool send(T first, T last, int flags_ = 0)
+    {
+        zmq::message_t msg(first, last);
+        int nbytes = zmq_msg_send(msg.handle(), _handle, flags_);
+        if (nbytes >= 0)
+            return true;
+        if (zmq_errno() == EAGAIN)
+            return false;
+        throw error_t();
+    }
 
 #ifdef ZMQ_HAS_RVALUE_REFS
-        inline context_t (context_t &&rhs) : ptr (rhs.ptr)
-        {
-            rhs.ptr = NULL;
-        }
-        inline context_t &operator = (context_t &&rhs)
-        {
-            std::swap (ptr, rhs.ptr);
-            return *this;
-        }
+#ifdef ZMQ_CPP11
+    ZMQ_DEPRECATED("from 4.3.1, use send taking message_t and send_flags")
+#endif
+    bool send(message_t &&msg_,
+              int flags_ = 0) // default until removed
+    {
+        #ifdef ZMQ_CPP11
+        return send(msg_, static_cast<send_flags>(flags_)).has_value();
+        #else
+        return send(msg_, flags_);
+        #endif
+    }
 #endif
 
-        inline ~context_t ()
-        {
-            close();
-        }
+#ifdef ZMQ_CPP11
+    send_result_t send(const_buffer buf, send_flags flags = send_flags::none)
+    {
+        const int nbytes =
+          zmq_send(_handle, buf.data(), buf.size(), static_cast<int>(flags));
+        if (nbytes >= 0)
+            return static_cast<size_t>(nbytes);
+        if (zmq_errno() == EAGAIN)
+            return {};
+        throw error_t();
+    }
 
-        inline void close()
-        {
-            if (ptr == NULL)
-                return;
-            int rc = zmq_ctx_destroy (ptr);
-            ZMQ_ASSERT (rc == 0);
-            ptr = NULL;
+    send_result_t send(message_t &msg, send_flags flags)
+    {
+        int nbytes = zmq_msg_send(msg.handle(), _handle, static_cast<int>(flags));
+        if (nbytes >= 0)
+            return static_cast<size_t>(nbytes);
+        if (zmq_errno() == EAGAIN)
+            return {};
+        throw error_t();
+    }
+
+    send_result_t send(message_t &&msg, send_flags flags)
+    {
+        return send(msg, flags);
+    }
+#endif
+
+#ifdef ZMQ_CPP11
+    ZMQ_DEPRECATED("from 4.3.1, use recv taking a mutable_buffer and recv_flags")
+#endif
+    size_t recv(void *buf_, size_t len_, int flags_ = 0)
+    {
+        int nbytes = zmq_recv(_handle, buf_, len_, flags_);
+        if (nbytes >= 0)
+            return static_cast<size_t>(nbytes);
+        if (zmq_errno() == EAGAIN)
+            return 0;
+        throw error_t();
+    }
+
+#ifdef ZMQ_CPP11
+    ZMQ_DEPRECATED("from 4.3.1, use recv taking a reference to message_t and recv_flags")
+#endif
+    bool recv(message_t *msg_, int flags_ = 0)
+    {
+        int nbytes = zmq_msg_recv(msg_->handle(), _handle, flags_);
+        if (nbytes >= 0)
+            return true;
+        if (zmq_errno() == EAGAIN)
+            return false;
+        throw error_t();
+    }
+
+#ifdef ZMQ_CPP11
+    ZMQ_NODISCARD
+    recv_buffer_result_t recv(mutable_buffer buf,
+                                    recv_flags flags = recv_flags::none)
+    {
+        const int nbytes =
+          zmq_recv(_handle, buf.data(), buf.size(), static_cast<int>(flags));
+        if (nbytes >= 0) {
+            return recv_buffer_size{(std::min)(static_cast<size_t>(nbytes), buf.size()),
+                                 static_cast<size_t>(nbytes)};
         }
+        if (zmq_errno() == EAGAIN)
+            return {};
+        throw error_t();
+    }
 
-        //  Be careful with this, it's probably only useful for
-        //  using the C api together with an existing C++ api.
-        //  Normally you should never need to use this.
-        inline operator void* ()
-        {
-            return ptr;
+    ZMQ_NODISCARD
+    recv_result_t recv(message_t &msg, recv_flags flags = recv_flags::none)
+    {
+        const int nbytes = zmq_msg_recv(msg.handle(), _handle, static_cast<int>(flags));
+        if (nbytes >= 0) {
+            assert(msg.size() == static_cast<size_t>(nbytes));
+            return static_cast<size_t>(nbytes);
         }
+        if (zmq_errno() == EAGAIN)
+            return {};
+        throw error_t();
+    }
+#endif
 
-    private:
+#if defined(ZMQ_BUILD_DRAFT_API) && ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 0)
+    void join(const char* group)
+    {
+        int rc = zmq_join(_handle, group);
+        if (rc != 0)
+            throw error_t();
+    }
 
-        void *ptr;
+    void leave(const char* group)
+    {
+        int rc = zmq_leave(_handle, group);
+        if (rc != 0)
+            throw error_t();
+    }
+#endif
 
-        context_t (const context_t&);
-        void operator = (const context_t&);
-    };
+    ZMQ_NODISCARD void *handle() ZMQ_NOTHROW { return _handle; }
+    ZMQ_NODISCARD const void *handle() const ZMQ_NOTHROW { return _handle; }
+
+    ZMQ_EXPLICIT operator bool() const ZMQ_NOTHROW { return _handle != ZMQ_NULLPTR; }
+    // note: non-const operator bool can be removed once
+    // operator void* is removed from socket_t
+    ZMQ_EXPLICIT operator bool() ZMQ_NOTHROW { return _handle != ZMQ_NULLPTR; }
+
+protected:
+    void *_handle;
+};
+} // namespace detail
+
+#ifdef ZMQ_CPP11
+enum class socket_type : int
+{
+    req = ZMQ_REQ,
+    rep = ZMQ_REP,
+    dealer = ZMQ_DEALER,
+    router = ZMQ_ROUTER,
+    pub = ZMQ_PUB,
+    sub = ZMQ_SUB,
+    xpub = ZMQ_XPUB,
+    xsub = ZMQ_XSUB,
+    push = ZMQ_PUSH,
+    pull = ZMQ_PULL,
+#if defined(ZMQ_BUILD_DRAFT_API) && ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 0)
+    server = ZMQ_SERVER,
+    client = ZMQ_CLIENT,
+    radio = ZMQ_RADIO,
+    dish = ZMQ_DISH,
+#endif
+#if ZMQ_VERSION_MAJOR >= 4
+    stream = ZMQ_STREAM,
+#endif
+    pair = ZMQ_PAIR
+};
+#endif
+
+struct from_handle_t
+{
+    struct _private {}; // disabling use other than with from_handle
+    ZMQ_CONSTEXPR_FN ZMQ_EXPLICIT from_handle_t(_private /*p*/) ZMQ_NOTHROW {}
+};
+
+ZMQ_CONSTEXPR_VAR from_handle_t from_handle = from_handle_t(from_handle_t::_private());
+
+// A non-owning nullable reference to a socket.
+// The reference is invalidated on socket close or destruction.
+class socket_ref : public detail::socket_base
+{
+  public:
+    socket_ref() ZMQ_NOTHROW : detail::socket_base() {}
+#ifdef ZMQ_CPP11
+    socket_ref(std::nullptr_t) ZMQ_NOTHROW : detail::socket_base() {}
+#endif
+    socket_ref(from_handle_t /*fh*/, void *handle) ZMQ_NOTHROW
+        : detail::socket_base(handle) {}
+};
+
+#ifdef ZMQ_CPP11
+inline bool operator==(socket_ref sr, std::nullptr_t /*p*/) ZMQ_NOTHROW
+{
+    return sr.handle() == nullptr;
+}
+inline bool operator==(std::nullptr_t /*p*/, socket_ref sr) ZMQ_NOTHROW
+{
+    return sr.handle() == nullptr;
+}
+inline bool operator!=(socket_ref sr, std::nullptr_t /*p*/) ZMQ_NOTHROW
+{
+    return !(sr == nullptr);
+}
+inline bool operator!=(std::nullptr_t /*p*/, socket_ref sr) ZMQ_NOTHROW
+{
+    return !(sr == nullptr);
+}
+#endif
+
+inline bool operator==(socket_ref a, socket_ref b) ZMQ_NOTHROW
+{
+    return std::equal_to<void*>()(a.handle(), b.handle());
+}
+inline bool operator!=(socket_ref a, socket_ref b) ZMQ_NOTHROW
+{
+    return !(a == b);
+}
+inline bool operator<(socket_ref a, socket_ref b) ZMQ_NOTHROW
+{
+    return std::less<void*>()(a.handle(), b.handle());
+}
+inline bool operator>(socket_ref a, socket_ref b) ZMQ_NOTHROW
+{
+    return b < a;
+}
+inline bool operator<=(socket_ref a, socket_ref b) ZMQ_NOTHROW
+{
+    return !(a > b);
+}
+inline bool operator>=(socket_ref a, socket_ref b) ZMQ_NOTHROW
+{
+    return !(a < b);
+}
 
-    class socket_t
+} // namespace zmq
+
+#ifdef ZMQ_CPP11
+namespace std
+{
+template<>
+struct hash<zmq::socket_ref>
+{
+    size_t operator()(zmq::socket_ref sr) const ZMQ_NOTHROW
     {
-        friend class monitor_t;
-    public:
+        return hash<void*>()(sr.handle());
+    }
+};
+} // namespace std
+#endif
 
-        inline socket_t (context_t &context_, int type_)
-        {
-            ctxptr = context_.ptr;
-            ptr = zmq_socket (context_.ptr, type_);
-            if (ptr == NULL)
-                throw error_t ();
-        }
+namespace zmq
+{
+
+class socket_t : public detail::socket_base
+{
+    friend class monitor_t;
+
+  public:
+    socket_t() ZMQ_NOTHROW
+      : detail::socket_base(ZMQ_NULLPTR)
+      , ctxptr(ZMQ_NULLPTR)
+    {
+    }
+
+    socket_t(context_t &context_, int type_)
+        : detail::socket_base(zmq_socket(static_cast<void*>(context_), type_))
+        , ctxptr(static_cast<void*>(context_))
+    {
+        if (_handle == ZMQ_NULLPTR)
+            throw error_t();
+    }
+
+#ifdef ZMQ_CPP11
+    socket_t(context_t &context_, socket_type type_)
+        : socket_t(context_, static_cast<int>(type_))
+    {
+    }
+#endif
 
 #ifdef ZMQ_HAS_RVALUE_REFS
-        inline socket_t(socket_t&& rhs) : ptr(rhs.ptr)
-        {
-            rhs.ptr = NULL;
-        }
-        inline socket_t& operator=(socket_t&& rhs)
-        {
-            std::swap(ptr, rhs.ptr);
-            return *this;
-        }
+    socket_t(socket_t &&rhs) ZMQ_NOTHROW : detail::socket_base(rhs._handle), ctxptr(rhs.ctxptr)
+    {
+        rhs._handle = ZMQ_NULLPTR;
+        rhs.ctxptr = ZMQ_NULLPTR;
+    }
+    socket_t &operator=(socket_t &&rhs) ZMQ_NOTHROW
+    {
+        close();
+        std::swap(_handle, rhs._handle);
+        return *this;
+    }
 #endif
 
-        inline ~socket_t ()
-        {
-            close();
-        }
+    ~socket_t() ZMQ_NOTHROW { close(); }
 
-        inline operator void* ()
-        {
-            return ptr;
-        }
+    operator void *() ZMQ_NOTHROW { return _handle; }
 
-        inline void close()
-        {
-            if(ptr == NULL)
-                // already closed
-                return ;
-            int rc = zmq_close (ptr);
-            ZMQ_ASSERT (rc == 0);
-            ptr = 0 ;
-        }
+    operator void const *() const ZMQ_NOTHROW { return _handle; }
 
-        inline void setsockopt (int option_, const void *optval_,
-            size_t optvallen_)
-        {
-            int rc = zmq_setsockopt (ptr, option_, optval_, optvallen_);
-            if (rc != 0)
-                throw error_t ();
-        }
+    void close() ZMQ_NOTHROW
+    {
+        if (_handle == ZMQ_NULLPTR)
+            // already closed
+            return;
+        int rc = zmq_close(_handle);
+        ZMQ_ASSERT(rc == 0);
+        _handle = ZMQ_NULLPTR;
+    }
 
-        inline void getsockopt (int option_, void *optval_,
-            size_t *optvallen_)
-        {
-            int rc = zmq_getsockopt (ptr, option_, optval_, optvallen_);
-            if (rc != 0)
-                throw error_t ();
-        }
-        
-        inline void bind (const char *addr_)
-        {
-            int rc = zmq_bind (ptr, addr_);
-            if (rc != 0)
-                throw error_t ();
-        }
+    void swap(socket_t &other) ZMQ_NOTHROW
+    {
+        std::swap(_handle, other._handle);
+        std::swap(ctxptr, other.ctxptr);
+    }
 
-        inline void unbind (const char *addr_)
-        {
-            int rc = zmq_unbind (ptr, addr_);
-            if (rc != 0)
-                throw error_t ();
-        }
+    operator socket_ref() ZMQ_NOTHROW
+    {
+        return socket_ref(from_handle, _handle);
+    }
 
-        inline void connect (const char *addr_)
-        {
-            int rc = zmq_connect (ptr, addr_);
-            if (rc != 0)
-                throw error_t ();
-        }
+  private:
+    void *ctxptr;
 
-        inline void disconnect (const char *addr_)
-        {
-            int rc = zmq_disconnect (ptr, addr_);
-            if (rc != 0)
-                throw error_t ();
-        }
+    socket_t(const socket_t &) ZMQ_DELETED_FUNCTION;
+    void operator=(const socket_t &) ZMQ_DELETED_FUNCTION;
 
-        inline bool connected()
-        {
-            return(ptr != NULL);
-        }
-        
-        inline size_t send (const void *buf_, size_t len_, int flags_ = 0)
-        {
-            int nbytes = zmq_send (ptr, buf_, len_, flags_);
-            if (nbytes >= 0)
-                return (size_t) nbytes;
-            if (zmq_errno () == EAGAIN)
-                return 0;
-            throw error_t ();
-        }
+    // used by monitor_t
+    socket_t(void *context_, int type_)
+        : detail::socket_base(zmq_socket(context_, type_))
+        , ctxptr(context_)
+    {
+        if (_handle == ZMQ_NULLPTR)
+            throw error_t();
+    }
+};
 
-        inline bool send (message_t &msg_, int flags_ = 0)
-        {
-            int nbytes = zmq_msg_send (&(msg_.msg), ptr, flags_);
-            if (nbytes >= 0)
-                return true;
-            if (zmq_errno () == EAGAIN)
-                return false;
-            throw error_t ();
-        }
+inline void swap(socket_t &a, socket_t &b) ZMQ_NOTHROW {
+    a.swap(b);
+}
+
+ZMQ_DEPRECATED("from 4.3.1, use proxy taking socket_t objects")
+inline void proxy(void *frontend, void *backend, void *capture)
+{
+    int rc = zmq_proxy(frontend, backend, capture);
+    if (rc != 0)
+        throw error_t();
+}
+
+inline void
+proxy(socket_ref frontend, socket_ref backend, socket_ref capture = socket_ref())
+{
+    int rc = zmq_proxy(frontend.handle(), backend.handle(), capture.handle());
+    if (rc != 0)
+        throw error_t();
+}
+
+#ifdef ZMQ_HAS_PROXY_STEERABLE
+ZMQ_DEPRECATED("from 4.3.1, use proxy_steerable taking socket_t objects")
+inline void
+proxy_steerable(void *frontend, void *backend, void *capture, void *control)
+{
+    int rc = zmq_proxy_steerable(frontend, backend, capture, control);
+    if (rc != 0)
+        throw error_t();
+}
+
+inline void proxy_steerable(socket_ref frontend,
+                            socket_ref backend,
+                            socket_ref capture,
+                            socket_ref control)
+{
+    int rc = zmq_proxy_steerable(frontend.handle(), backend.handle(),
+                                 capture.handle(), control.handle());
+    if (rc != 0)
+        throw error_t();
+}
+#endif
+
+class monitor_t
+{
+  public:
+    monitor_t() : _socket(), _monitor_socket() {}
+
+    virtual ~monitor_t()
+    {
+        close();
+    }
 
 #ifdef ZMQ_HAS_RVALUE_REFS
-        inline bool send (message_t &&msg_, int flags_ = 0)
-        {
-            return send(msg_, flags_);
-        }
+    monitor_t(monitor_t &&rhs) ZMQ_NOTHROW : _socket(), _monitor_socket()
+    {
+        std::swap(_socket, rhs._socket);
+        std::swap(_monitor_socket, rhs._monitor_socket);
+    }
+
+    monitor_t &operator=(monitor_t &&rhs) ZMQ_NOTHROW
+    {
+        close();
+        _socket = socket_ref();
+        std::swap(_socket, rhs._socket);
+        std::swap(_monitor_socket, rhs._monitor_socket);
+        return *this;
+    }
 #endif
 
-        inline size_t recv (void *buf_, size_t len_, int flags_ = 0)
-        {
-            int nbytes = zmq_recv (ptr, buf_, len_, flags_);
-            if (nbytes >= 0)
-                return (size_t) nbytes;
-            if (zmq_errno () == EAGAIN)
-                return 0;
-            throw error_t ();
-        }
 
-        inline bool recv (message_t *msg_, int flags_ = 0)
-        {
-            int nbytes = zmq_msg_recv (&(msg_->msg), ptr, flags_);
-            if (nbytes >= 0)
-                return true;
-            if (zmq_errno () == EAGAIN)
-                return false;
-            throw error_t ();
+    void
+    monitor(socket_t &socket, std::string const &addr, int events = ZMQ_EVENT_ALL)
+    {
+        monitor(socket, addr.c_str(), events);
+    }
+
+    void monitor(socket_t &socket, const char *addr_, int events = ZMQ_EVENT_ALL)
+    {
+        init(socket, addr_, events);
+        while (true) {
+            check_event(-1);
         }
-        
-    private:
-        void *ptr;
-        void *ctxptr;
+    }
 
-        socket_t (const socket_t&) ZMQ_DELETED_FUNCTION;
-        void operator = (const socket_t&) ZMQ_DELETED_FUNCTION;
-    };
+    void init(socket_t &socket, std::string const &addr, int events = ZMQ_EVENT_ALL)
+    {
+        init(socket, addr.c_str(), events);
+    }
 
-    class monitor_t
+    void init(socket_t &socket, const char *addr_, int events = ZMQ_EVENT_ALL)
     {
-    public:
-        monitor_t() : socketPtr(NULL) {}
-        virtual ~monitor_t() {}
+        int rc = zmq_socket_monitor(socket.handle(), addr_, events);
+        if (rc != 0)
+            throw error_t();
+
+        _socket = socket;
+        _monitor_socket = socket_t(socket.ctxptr, ZMQ_PAIR);
+        _monitor_socket.connect(addr_);
+
+        on_monitor_started();
+    }
+
+    bool check_event(int timeout = 0)
+    {
+        assert(_monitor_socket);
+
+        zmq_msg_t eventMsg;
+        zmq_msg_init(&eventMsg);
+
+        zmq::pollitem_t items[] = {
+          {_monitor_socket.handle(), 0, ZMQ_POLLIN, 0},
+        };
+
+        zmq::poll(&items[0], 1, timeout);
+
+        if (items[0].revents & ZMQ_POLLIN) {
+            int rc = zmq_msg_recv(&eventMsg, _monitor_socket.handle(), 0);
+            if (rc == -1 && zmq_errno() == ETERM)
+                return false;
+            assert(rc != -1);
+
+        } else {
+            zmq_msg_close(&eventMsg);
+            return false;
+        }
 
-        void monitor(socket_t &socket, const char *addr_, int events = ZMQ_EVENT_ALL)
-        {
-            int rc = zmq_socket_monitor(socket.ptr, addr_, events);
-            if (rc != 0)
-                throw error_t ();
-
-            socketPtr = socket.ptr;
-            void *s = zmq_socket (socket.ctxptr, ZMQ_PAIR);
-            assert (s);
-
-            rc = zmq_connect (s, addr_);
-            assert (rc == 0);
-            
-            on_monitor_started();
-            
-            while (true) {
-                zmq_msg_t eventMsg;
-                zmq_msg_init (&eventMsg);
-                rc = zmq_recvmsg (s, &eventMsg, 0);
-                if (rc == -1 && zmq_errno() == ETERM)
-                    break;
-                assert (rc != -1);
 #if ZMQ_VERSION_MAJOR >= 4
-                const char* data = static_cast<const char*>(zmq_msg_data(&eventMsg));
-                zmq_event_t msgEvent;
-                memcpy(&msgEvent.event, data, sizeof(uint16_t)); data += sizeof(uint16_t);
-                memcpy(&msgEvent.value, data, sizeof(int32_t));
-                zmq_event_t* event = &msgEvent;
+        const char *data = static_cast<const char *>(zmq_msg_data(&eventMsg));
+        zmq_event_t msgEvent;
+        memcpy(&msgEvent.event, data, sizeof(uint16_t));
+        data += sizeof(uint16_t);
+        memcpy(&msgEvent.value, data, sizeof(int32_t));
+        zmq_event_t *event = &msgEvent;
 #else
-                zmq_event_t* event = static_cast<zmq_event_t*>(zmq_msg_data(&eventMsg));
+        zmq_event_t *event = static_cast<zmq_event_t *>(zmq_msg_data(&eventMsg));
 #endif
-                
+
 #ifdef ZMQ_NEW_MONITOR_EVENT_LAYOUT
-                zmq_msg_t addrMsg;
-                zmq_msg_init (&addrMsg);
-                rc = zmq_recvmsg (s, &addrMsg, 0);
-                if (rc == -1 && zmq_errno() == ETERM)
-                    break;
-                assert (rc != -1);
-                const char* str = static_cast<const char*>(zmq_msg_data (&addrMsg));
-                std::string address(str, str + zmq_msg_size(&addrMsg));
-                zmq_msg_close (&addrMsg);
+        zmq_msg_t addrMsg;
+        zmq_msg_init(&addrMsg);
+        int rc = zmq_msg_recv(&addrMsg, _monitor_socket.handle(), 0);
+        if (rc == -1 && zmq_errno() == ETERM) {
+            zmq_msg_close(&eventMsg);
+            return false;
+        }
+
+        assert(rc != -1);
+        const char *str = static_cast<const char *>(zmq_msg_data(&addrMsg));
+        std::string address(str, str + zmq_msg_size(&addrMsg));
+        zmq_msg_close(&addrMsg);
 #else
-                // Bit of a hack, but all events in the zmq_event_t union have the same layout so this will work for all event types.
-                std::string address = event->data.connected.addr;
+        // Bit of a hack, but all events in the zmq_event_t union have the same layout so this will work for all event types.
+        std::string address = event->data.connected.addr;
 #endif
 
 #ifdef ZMQ_EVENT_MONITOR_STOPPED
-                if (event->event == ZMQ_EVENT_MONITOR_STOPPED)
-                    break;
-#endif
-
-                switch (event->event) {
-                case ZMQ_EVENT_CONNECTED:
-                    on_event_connected(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_CONNECT_DELAYED:
-                    on_event_connect_delayed(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_CONNECT_RETRIED:
-                    on_event_connect_retried(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_LISTENING:
-                    on_event_listening(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_BIND_FAILED:
-                    on_event_bind_failed(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_ACCEPTED:
-                    on_event_accepted(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_ACCEPT_FAILED:
-                    on_event_accept_failed(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_CLOSED:
-                    on_event_closed(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_CLOSE_FAILED:
-                    on_event_close_failed(*event, address.c_str());
-                    break;
-                case ZMQ_EVENT_DISCONNECTED:
-                    on_event_disconnected(*event, address.c_str());
-                    break;
-                default:
-                    on_event_unknown(*event, address.c_str());
-                    break;
-                }
-                zmq_msg_close (&eventMsg);
-            }
-            zmq_close (s);
-            socketPtr = NULL;
+        if (event->event == ZMQ_EVENT_MONITOR_STOPPED) {
+            zmq_msg_close(&eventMsg);
+            return false;
+        }
+
+#endif
+
+        switch (event->event) {
+            case ZMQ_EVENT_CONNECTED:
+                on_event_connected(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_CONNECT_DELAYED:
+                on_event_connect_delayed(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_CONNECT_RETRIED:
+                on_event_connect_retried(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_LISTENING:
+                on_event_listening(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_BIND_FAILED:
+                on_event_bind_failed(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_ACCEPTED:
+                on_event_accepted(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_ACCEPT_FAILED:
+                on_event_accept_failed(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_CLOSED:
+                on_event_closed(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_CLOSE_FAILED:
+                on_event_close_failed(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_DISCONNECTED:
+                on_event_disconnected(*event, address.c_str());
+                break;
+#ifdef ZMQ_BUILD_DRAFT_API
+#if ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 3)
+            case ZMQ_EVENT_HANDSHAKE_FAILED_NO_DETAIL:
+                on_event_handshake_failed_no_detail(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_HANDSHAKE_FAILED_PROTOCOL:
+                on_event_handshake_failed_protocol(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_HANDSHAKE_FAILED_AUTH:
+                on_event_handshake_failed_auth(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_HANDSHAKE_SUCCEEDED:
+                on_event_handshake_succeeded(*event, address.c_str());
+                break;
+#elif ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 1)
+            case ZMQ_EVENT_HANDSHAKE_FAILED:
+                on_event_handshake_failed(*event, address.c_str());
+                break;
+            case ZMQ_EVENT_HANDSHAKE_SUCCEED:
+                on_event_handshake_succeed(*event, address.c_str());
+                break;
+#endif
+#endif
+            default:
+                on_event_unknown(*event, address.c_str());
+                break;
         }
+        zmq_msg_close(&eventMsg);
+
+        return true;
+    }
 
 #ifdef ZMQ_EVENT_MONITOR_STOPPED
-        void abort()
-        {
-            if (socketPtr)
-                zmq_socket_monitor(socketPtr, NULL, 0);
+    void abort()
+    {
+        if (_socket)
+            zmq_socket_monitor(_socket.handle(), ZMQ_NULLPTR, 0);
+
+        _socket = socket_ref();
+    }
+#endif
+    virtual void on_monitor_started() {}
+    virtual void on_event_connected(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_connect_delayed(const zmq_event_t &event_,
+                                          const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_connect_retried(const zmq_event_t &event_,
+                                          const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_listening(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_bind_failed(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_accepted(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_accept_failed(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_closed(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_close_failed(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_disconnected(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+#if ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 3)
+    virtual void on_event_handshake_failed_no_detail(const zmq_event_t &event_,
+                                                     const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_handshake_failed_protocol(const zmq_event_t &event_,
+                                                    const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_handshake_failed_auth(const zmq_event_t &event_,
+                                                const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_handshake_succeeded(const zmq_event_t &event_,
+                                              const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+#elif ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 1)
+    virtual void on_event_handshake_failed(const zmq_event_t &event_,
+                                           const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+    virtual void on_event_handshake_succeed(const zmq_event_t &event_,
+                                            const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+#endif
+    virtual void on_event_unknown(const zmq_event_t &event_, const char *addr_)
+    {
+        (void) event_;
+        (void) addr_;
+    }
+
+  private:
+    monitor_t(const monitor_t &) ZMQ_DELETED_FUNCTION;
+    void operator=(const monitor_t &) ZMQ_DELETED_FUNCTION;
+
+    socket_ref _socket;
+    socket_t _monitor_socket;
+
+    void close() ZMQ_NOTHROW
+    {
+        if (_socket)
+            zmq_socket_monitor(_socket.handle(), ZMQ_NULLPTR, 0);
+        _monitor_socket.close();
+    }
+};
+
+#if defined(ZMQ_BUILD_DRAFT_API) && defined(ZMQ_CPP11) && defined(ZMQ_HAVE_POLLER)
+
+// polling events
+enum class event_flags : short
+{
+    none = 0,
+    pollin = ZMQ_POLLIN,
+    pollout = ZMQ_POLLOUT,
+    pollerr = ZMQ_POLLERR,
+    pollpri = ZMQ_POLLPRI
+};
+
+constexpr event_flags operator|(event_flags a, event_flags b) noexcept
+{
+    return detail::enum_bit_or(a, b);
+}
+constexpr event_flags operator&(event_flags a, event_flags b) noexcept
+{
+    return detail::enum_bit_and(a, b);
+}
+constexpr event_flags operator^(event_flags a, event_flags b) noexcept
+{
+    return detail::enum_bit_xor(a, b);
+}
+constexpr event_flags operator~(event_flags a) noexcept
+{
+    return detail::enum_bit_not(a);
+}
+
+struct no_user_data;
+
+// layout compatible with zmq_poller_event_t
+template<class T = no_user_data>
+struct poller_event
+{
+    socket_ref socket;
+#ifdef _WIN32
+    SOCKET fd;
+#else
+    int fd;
+#endif
+    T *user_data;
+    event_flags events;
+};
+
+template<typename T = no_user_data> class poller_t
+{
+  public:
+    using event_type = poller_event<T>;
+
+    poller_t() : poller_ptr(zmq_poller_new())
+    {
+        if (!poller_ptr)
+            throw error_t();
+    }
+
+    template<
+      typename Dummy = void,
+      typename =
+        typename std::enable_if<!std::is_same<T, no_user_data>::value, Dummy>::type>
+    void add(zmq::socket_ref socket, event_flags events, T *user_data)
+    {
+        add_impl(socket, events, user_data);
+    }
+
+    void add(zmq::socket_ref socket, event_flags events)
+    {
+        add_impl(socket, events, nullptr);
+    }
+
+    void remove(zmq::socket_ref socket)
+    {
+        if (0 != zmq_poller_remove(poller_ptr.get(), socket.handle())) {
+            throw error_t();
         }
+    }
+
+    void modify(zmq::socket_ref socket, event_flags events)
+    {
+        if (0
+            != zmq_poller_modify(poller_ptr.get(), socket.handle(),
+                                 static_cast<short>(events))) {
+            throw error_t();
+        }
+    }
+
+    size_t wait_all(std::vector<event_type> &poller_events,
+                    const std::chrono::milliseconds timeout)
+    {
+        int rc = zmq_poller_wait_all(
+          poller_ptr.get(),
+          reinterpret_cast<zmq_poller_event_t *>(poller_events.data()),
+          static_cast<int>(poller_events.size()),
+          static_cast<long>(timeout.count()));
+        if (rc > 0)
+            return static_cast<size_t>(rc);
+
+#if ZMQ_VERSION >= ZMQ_MAKE_VERSION(4, 2, 3)
+        if (zmq_errno() == EAGAIN)
+#else
+        if (zmq_errno() == ETIMEDOUT)
 #endif
-        virtual void on_monitor_started() {}
-        virtual void on_event_connected(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_connect_delayed(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_connect_retried(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_listening(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_bind_failed(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_accepted(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_accept_failed(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_closed(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_close_failed(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_disconnected(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-        virtual void on_event_unknown(const zmq_event_t &event_, const char* addr_) { (void)event_; (void)addr_; }
-    private:
-        void* socketPtr;
+            return 0;
+
+        throw error_t();
+    }
+
+  private:
+    struct destroy_poller_t
+    {
+        void operator()(void *ptr) noexcept
+        {
+            int rc = zmq_poller_destroy(&ptr);
+            ZMQ_ASSERT(rc == 0);
+        }
     };
+
+    std::unique_ptr<void, destroy_poller_t> poller_ptr;
+
+    void add_impl(zmq::socket_ref socket, event_flags events, T *user_data)
+    {
+        if (0
+            != zmq_poller_add(poller_ptr.get(), socket.handle(),
+                              user_data, static_cast<short>(events))) {
+            throw error_t();
+        }
+    }
+};
+#endif //  defined(ZMQ_BUILD_DRAFT_API) && defined(ZMQ_CPP11) && defined(ZMQ_HAVE_POLLER)
+
+inline std::ostream &operator<<(std::ostream &os, const message_t &msg)
+{
+    return os << msg.str();
 }
 
-#endif
+} // namespace zmq
+
+#endif // __ZMQ_HPP_INCLUDED__