[DEV] add v1.66.0

libs/asio/example/cpp11/allocation/Jamfile.v2

@@ -0,0 +1,43 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe server
+  : server.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/allocation/server.cpp

@@ -0,0 +1,255 @@
+//
+// server.cpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <array>
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::tcp;
+
+// Class to manage the memory to be used for handler-based custom allocation.
+// It contains a single block of memory which may be returned for allocation
+// requests. If the memory is in use when an allocation request is made, the
+// allocator delegates allocation to the global heap.
+class handler_memory
+{
+public:
+  handler_memory()
+    : in_use_(false)
+  {
+  }
+
+  handler_memory(const handler_memory&) = delete;
+  handler_memory& operator=(const handler_memory&) = delete;
+
+  void* allocate(std::size_t size)
+  {
+    if (!in_use_ && size < sizeof(storage_))
+    {
+      in_use_ = true;
+      return &storage_;
+    }
+    else
+    {
+      return ::operator new(size);
+    }
+  }
+
+  void deallocate(void* pointer)
+  {
+    if (pointer == &storage_)
+    {
+      in_use_ = false;
+    }
+    else
+    {
+      ::operator delete(pointer);
+    }
+  }
+
+private:
+  // Storage space used for handler-based custom memory allocation.
+  typename std::aligned_storage<1024>::type storage_;
+
+  // Whether the handler-based custom allocation storage has been used.
+  bool in_use_;
+};
+
+// The allocator to be associated with the handler objects. This allocator only
+// needs to satisfy the C++11 minimal allocator requirements.
+template <typename T>
+class handler_allocator
+{
+public:
+  using value_type = T;
+
+  explicit handler_allocator(handler_memory& mem)
+    : memory_(mem)
+  {
+  }
+
+  template <typename U>
+  handler_allocator(const handler_allocator<U>& other) noexcept
+    : memory_(other.memory_)
+  {
+  }
+
+  bool operator==(const handler_allocator& other) const noexcept
+  {
+    return &memory_ == &other.memory_;
+  }
+
+  bool operator!=(const handler_allocator& other) const noexcept
+  {
+    return &memory_ != &other.memory_;
+  }
+
+  T* allocate(std::size_t n) const
+  {
+    return static_cast<T*>(memory_.allocate(sizeof(T) * n));
+  }
+
+  void deallocate(T* p, std::size_t /*n*/) const
+  {
+    return memory_.deallocate(p);
+  }
+
+private:
+  template <typename> friend class handler_allocator;
+
+  // The underlying memory.
+  handler_memory& memory_;
+};
+
+// Wrapper class template for handler objects to allow handler memory
+// allocation to be customised. The allocator_type type and get_allocator()
+// member function are used by the asynchronous operations to obtain the
+// allocator. Calls to operator() are forwarded to the encapsulated handler.
+template <typename Handler>
+class custom_alloc_handler
+{
+public:
+  using allocator_type = handler_allocator<Handler>;
+
+  custom_alloc_handler(handler_memory& m, Handler h)
+    : memory_(m),
+      handler_(h)
+  {
+  }
+
+  allocator_type get_allocator() const noexcept
+  {
+    return allocator_type(memory_);
+  }
+
+  template <typename ...Args>
+  void operator()(Args&&... args)
+  {
+    handler_(std::forward<Args>(args)...);
+  }
+
+private:
+  handler_memory& memory_;
+  Handler handler_;
+};
+
+// Helper function to wrap a handler object to add custom allocation.
+template <typename Handler>
+inline custom_alloc_handler<Handler> make_custom_alloc_handler(
+    handler_memory& m, Handler h)
+{
+  return custom_alloc_handler<Handler>(m, h);
+}
+
+class session
+  : public std::enable_shared_from_this<session>
+{
+public:
+  session(tcp::socket socket)
+    : socket_(std::move(socket))
+  {
+  }
+
+  void start()
+  {
+    do_read();
+  }
+
+private:
+  void do_read()
+  {
+    auto self(shared_from_this());
+    socket_.async_read_some(boost::asio::buffer(data_),
+        make_custom_alloc_handler(handler_memory_,
+          [this, self](boost::system::error_code ec, std::size_t length)
+          {
+            if (!ec)
+            {
+              do_write(length);
+            }
+          }));
+  }
+
+  void do_write(std::size_t length)
+  {
+    auto self(shared_from_this());
+    boost::asio::async_write(socket_, boost::asio::buffer(data_, length),
+        make_custom_alloc_handler(handler_memory_,
+          [this, self](boost::system::error_code ec, std::size_t /*length*/)
+          {
+            if (!ec)
+            {
+              do_read();
+            }
+          }));
+  }
+
+  // The socket used to communicate with the client.
+  tcp::socket socket_;
+
+  // Buffer used to store data received from the client.
+  std::array<char, 1024> data_;
+
+  // The memory to use for handler-based custom memory allocation.
+  handler_memory handler_memory_;
+};
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, short port)
+    : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, tcp::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<session>(std::move(socket))->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  tcp::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: server <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+    server s(io_context, std::atoi(argv[1]));
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/buffers/Jamfile.v2

@@ -0,0 +1,43 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe server
+  : reference_counted.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/buffers/reference_counted.cpp

@@ -0,0 +1,121 @@
+//
+// reference_counted.cpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/asio.hpp>
+#include <iostream>
+#include <memory>
+#include <utility>
+#include <vector>
+
+using boost::asio::ip::tcp;
+
+// A reference-counted non-modifiable buffer class.
+class shared_const_buffer
+{
+public:
+  // Construct from a std::string.
+  explicit shared_const_buffer(const std::string& data)
+    : data_(new std::vector<char>(data.begin(), data.end())),
+      buffer_(boost::asio::buffer(*data_))
+  {
+  }
+
+  // Implement the ConstBufferSequence requirements.
+  typedef boost::asio::const_buffer value_type;
+  typedef const boost::asio::const_buffer* const_iterator;
+  const boost::asio::const_buffer* begin() const { return &buffer_; }
+  const boost::asio::const_buffer* end() const { return &buffer_ + 1; }
+
+private:
+  std::shared_ptr<std::vector<char> > data_;
+  boost::asio::const_buffer buffer_;
+};
+
+class session
+  : public std::enable_shared_from_this<session>
+{
+public:
+  session(tcp::socket socket)
+    : socket_(std::move(socket))
+  {
+  }
+
+  void start()
+  {
+    do_write();
+  }
+
+private:
+  void do_write()
+  {
+    std::time_t now = std::time(0);
+    shared_const_buffer buffer(std::ctime(&now));
+
+    auto self(shared_from_this());
+    boost::asio::async_write(socket_, buffer,
+        [this, self](boost::system::error_code /*ec*/, std::size_t /*length*/)
+        {
+        });
+  }
+
+  // The socket used to communicate with the client.
+  tcp::socket socket_;
+};
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, short port)
+    : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, tcp::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<session>(std::move(socket))->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  tcp::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: reference_counted <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    server s(io_context, std::atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/chat/Jamfile.v2

@@ -0,0 +1,47 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+project
+  : requirements
+    <library>/boost/system//boost_system
+    <library>/boost/thread//boost_thread
+    <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe chat_server : chat_server.cpp ;
+exe chat_client : chat_client.cpp ;

libs/asio/example/cpp11/chat/chat_client.cpp

@@ -0,0 +1,167 @@
+//
+// chat_client.cpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <deque>
+#include <iostream>
+#include <thread>
+#include <boost/asio.hpp>
+#include "chat_message.hpp"
+
+using boost::asio::ip::tcp;
+
+typedef std::deque<chat_message> chat_message_queue;
+
+class chat_client
+{
+public:
+  chat_client(boost::asio::io_context& io_context,
+      const tcp::resolver::results_type& endpoints)
+    : io_context_(io_context),
+      socket_(io_context)
+  {
+    do_connect(endpoints);
+  }
+
+  void write(const chat_message& msg)
+  {
+    boost::asio::post(io_context_,
+        [this, msg]()
+        {
+          bool write_in_progress = !write_msgs_.empty();
+          write_msgs_.push_back(msg);
+          if (!write_in_progress)
+          {
+            do_write();
+          }
+        });
+  }
+
+  void close()
+  {
+    boost::asio::post(io_context_, [this]() { socket_.close(); });
+  }
+
+private:
+  void do_connect(const tcp::resolver::results_type& endpoints)
+  {
+    boost::asio::async_connect(socket_, endpoints,
+        [this](boost::system::error_code ec, tcp::endpoint)
+        {
+          if (!ec)
+          {
+            do_read_header();
+          }
+        });
+  }
+
+  void do_read_header()
+  {
+    boost::asio::async_read(socket_,
+        boost::asio::buffer(read_msg_.data(), chat_message::header_length),
+        [this](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec && read_msg_.decode_header())
+          {
+            do_read_body();
+          }
+          else
+          {
+            socket_.close();
+          }
+        });
+  }
+
+  void do_read_body()
+  {
+    boost::asio::async_read(socket_,
+        boost::asio::buffer(read_msg_.body(), read_msg_.body_length()),
+        [this](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+          {
+            std::cout.write(read_msg_.body(), read_msg_.body_length());
+            std::cout << "\n";
+            do_read_header();
+          }
+          else
+          {
+            socket_.close();
+          }
+        });
+  }
+
+  void do_write()
+  {
+    boost::asio::async_write(socket_,
+        boost::asio::buffer(write_msgs_.front().data(),
+          write_msgs_.front().length()),
+        [this](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+          {
+            write_msgs_.pop_front();
+            if (!write_msgs_.empty())
+            {
+              do_write();
+            }
+          }
+          else
+          {
+            socket_.close();
+          }
+        });
+  }
+
+private:
+  boost::asio::io_context& io_context_;
+  tcp::socket socket_;
+  chat_message read_msg_;
+  chat_message_queue write_msgs_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 3)
+    {
+      std::cerr << "Usage: chat_client <host> <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    tcp::resolver resolver(io_context);
+    auto endpoints = resolver.resolve(argv[1], argv[2]);
+    chat_client c(io_context, endpoints);
+
+    std::thread t([&io_context](){ io_context.run(); });
+
+    char line[chat_message::max_body_length + 1];
+    while (std::cin.getline(line, chat_message::max_body_length + 1))
+    {
+      chat_message msg;
+      msg.body_length(std::strlen(line));
+      std::memcpy(msg.body(), line, msg.body_length());
+      msg.encode_header();
+      c.write(msg);
+    }
+
+    c.close();
+    t.join();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/chat/chat_message.hpp

@@ -0,0 +1,91 @@
+//
+// chat_message.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef CHAT_MESSAGE_HPP
+#define CHAT_MESSAGE_HPP
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+class chat_message
+{
+public:
+  enum { header_length = 4 };
+  enum { max_body_length = 512 };
+
+  chat_message()
+    : body_length_(0)
+  {
+  }
+
+  const char* data() const
+  {
+    return data_;
+  }
+
+  char* data()
+  {
+    return data_;
+  }
+
+  std::size_t length() const
+  {
+    return header_length + body_length_;
+  }
+
+  const char* body() const
+  {
+    return data_ + header_length;
+  }
+
+  char* body()
+  {
+    return data_ + header_length;
+  }
+
+  std::size_t body_length() const
+  {
+    return body_length_;
+  }
+
+  void body_length(std::size_t new_length)
+  {
+    body_length_ = new_length;
+    if (body_length_ > max_body_length)
+      body_length_ = max_body_length;
+  }
+
+  bool decode_header()
+  {
+    char header[header_length + 1] = "";
+    std::strncat(header, data_, header_length);
+    body_length_ = std::atoi(header);
+    if (body_length_ > max_body_length)
+    {
+      body_length_ = 0;
+      return false;
+    }
+    return true;
+  }
+
+  void encode_header()
+  {
+    char header[header_length + 1] = "";
+    std::sprintf(header, "%4d", static_cast<int>(body_length_));
+    std::memcpy(data_, header, header_length);
+  }
+
+private:
+  char data_[header_length + max_body_length];
+  std::size_t body_length_;
+};
+
+#endif // CHAT_MESSAGE_HPP

libs/asio/example/cpp11/chat/chat_server.cpp

@@ -0,0 +1,227 @@
+//
+// chat_server.cpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <deque>
+#include <iostream>
+#include <list>
+#include <memory>
+#include <set>
+#include <utility>
+#include <boost/asio.hpp>
+#include "chat_message.hpp"
+
+using boost::asio::ip::tcp;
+
+//----------------------------------------------------------------------
+
+typedef std::deque<chat_message> chat_message_queue;
+
+//----------------------------------------------------------------------
+
+class chat_participant
+{
+public:
+  virtual ~chat_participant() {}
+  virtual void deliver(const chat_message& msg) = 0;
+};
+
+typedef std::shared_ptr<chat_participant> chat_participant_ptr;
+
+//----------------------------------------------------------------------
+
+class chat_room
+{
+public:
+  void join(chat_participant_ptr participant)
+  {
+    participants_.insert(participant);
+    for (auto msg: recent_msgs_)
+      participant->deliver(msg);
+  }
+
+  void leave(chat_participant_ptr participant)
+  {
+    participants_.erase(participant);
+  }
+
+  void deliver(const chat_message& msg)
+  {
+    recent_msgs_.push_back(msg);
+    while (recent_msgs_.size() > max_recent_msgs)
+      recent_msgs_.pop_front();
+
+    for (auto participant: participants_)
+      participant->deliver(msg);
+  }
+
+private:
+  std::set<chat_participant_ptr> participants_;
+  enum { max_recent_msgs = 100 };
+  chat_message_queue recent_msgs_;
+};
+
+//----------------------------------------------------------------------
+
+class chat_session
+  : public chat_participant,
+    public std::enable_shared_from_this<chat_session>
+{
+public:
+  chat_session(tcp::socket socket, chat_room& room)
+    : socket_(std::move(socket)),
+      room_(room)
+  {
+  }
+
+  void start()
+  {
+    room_.join(shared_from_this());
+    do_read_header();
+  }
+
+  void deliver(const chat_message& msg)
+  {
+    bool write_in_progress = !write_msgs_.empty();
+    write_msgs_.push_back(msg);
+    if (!write_in_progress)
+    {
+      do_write();
+    }
+  }
+
+private:
+  void do_read_header()
+  {
+    auto self(shared_from_this());
+    boost::asio::async_read(socket_,
+        boost::asio::buffer(read_msg_.data(), chat_message::header_length),
+        [this, self](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec && read_msg_.decode_header())
+          {
+            do_read_body();
+          }
+          else
+          {
+            room_.leave(shared_from_this());
+          }
+        });
+  }
+
+  void do_read_body()
+  {
+    auto self(shared_from_this());
+    boost::asio::async_read(socket_,
+        boost::asio::buffer(read_msg_.body(), read_msg_.body_length()),
+        [this, self](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+          {
+            room_.deliver(read_msg_);
+            do_read_header();
+          }
+          else
+          {
+            room_.leave(shared_from_this());
+          }
+        });
+  }
+
+  void do_write()
+  {
+    auto self(shared_from_this());
+    boost::asio::async_write(socket_,
+        boost::asio::buffer(write_msgs_.front().data(),
+          write_msgs_.front().length()),
+        [this, self](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+          {
+            write_msgs_.pop_front();
+            if (!write_msgs_.empty())
+            {
+              do_write();
+            }
+          }
+          else
+          {
+            room_.leave(shared_from_this());
+          }
+        });
+  }
+
+  tcp::socket socket_;
+  chat_room& room_;
+  chat_message read_msg_;
+  chat_message_queue write_msgs_;
+};
+
+//----------------------------------------------------------------------
+
+class chat_server
+{
+public:
+  chat_server(boost::asio::io_context& io_context,
+      const tcp::endpoint& endpoint)
+    : acceptor_(io_context, endpoint)
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, tcp::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<chat_session>(std::move(socket), room_)->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  tcp::acceptor acceptor_;
+  chat_room room_;
+};
+
+//----------------------------------------------------------------------
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc < 2)
+    {
+      std::cerr << "Usage: chat_server <port> [<port> ...]\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    std::list<chat_server> servers;
+    for (int i = 1; i < argc; ++i)
+    {
+      tcp::endpoint endpoint(tcp::v4(), std::atoi(argv[i]));
+      servers.emplace_back(io_context, endpoint);
+    }
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/echo/Jamfile.v2

@@ -0,0 +1,51 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+project
+  : requirements
+    <library>/boost/system//boost_system
+    <library>/boost/thread//boost_thread
+    <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe async_tcp_echo_server : async_tcp_echo_server.cpp ;
+exe async_udp_echo_server : async_udp_echo_server.cpp ;
+exe blocking_tcp_echo_client : blocking_tcp_echo_client.cpp ;
+exe blocking_tcp_echo_server : blocking_tcp_echo_server.cpp ;
+exe blocking_udp_echo_client : blocking_udp_echo_client.cpp ;
+exe blocking_udp_echo_server : blocking_udp_echo_server.cpp ;

libs/asio/example/cpp11/echo/async_tcp_echo_server.cpp

@@ -0,0 +1,114 @@
+//
+// async_tcp_echo_server.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+#include <utility>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::tcp;
+
+class session
+  : public std::enable_shared_from_this<session>
+{
+public:
+  session(tcp::socket socket)
+    : socket_(std::move(socket))
+  {
+  }
+
+  void start()
+  {
+    do_read();
+  }
+
+private:
+  void do_read()
+  {
+    auto self(shared_from_this());
+    socket_.async_read_some(boost::asio::buffer(data_, max_length),
+        [this, self](boost::system::error_code ec, std::size_t length)
+        {
+          if (!ec)
+          {
+            do_write(length);
+          }
+        });
+  }
+
+  void do_write(std::size_t length)
+  {
+    auto self(shared_from_this());
+    boost::asio::async_write(socket_, boost::asio::buffer(data_, length),
+        [this, self](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+          {
+            do_read();
+          }
+        });
+  }
+
+  tcp::socket socket_;
+  enum { max_length = 1024 };
+  char data_[max_length];
+};
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, short port)
+    : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, tcp::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<session>(std::move(socket))->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  tcp::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: async_tcp_echo_server <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    server s(io_context, std::atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/echo/async_udp_echo_server.cpp

@@ -0,0 +1,82 @@
+//
+// async_udp_echo_server.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <iostream>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::udp;
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, short port)
+    : socket_(io_context, udp::endpoint(udp::v4(), port))
+  {
+    do_receive();
+  }
+
+  void do_receive()
+  {
+    socket_.async_receive_from(
+        boost::asio::buffer(data_, max_length), sender_endpoint_,
+        [this](boost::system::error_code ec, std::size_t bytes_recvd)
+        {
+          if (!ec && bytes_recvd > 0)
+          {
+            do_send(bytes_recvd);
+          }
+          else
+          {
+            do_receive();
+          }
+        });
+  }
+
+  void do_send(std::size_t length)
+  {
+    socket_.async_send_to(
+        boost::asio::buffer(data_, length), sender_endpoint_,
+        [this](boost::system::error_code /*ec*/, std::size_t /*bytes_sent*/)
+        {
+          do_receive();
+        });
+  }
+
+private:
+  udp::socket socket_;
+  udp::endpoint sender_endpoint_;
+  enum { max_length = 1024 };
+  char data_[max_length];
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: async_udp_echo_server <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    server s(io_context, std::atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/echo/blocking_tcp_echo_client.cpp

@@ -0,0 +1,55 @@
+//
+// blocking_tcp_echo_client.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::tcp;
+
+enum { max_length = 1024 };
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 3)
+    {
+      std::cerr << "Usage: blocking_tcp_echo_client <host> <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    tcp::socket s(io_context);
+    tcp::resolver resolver(io_context);
+    boost::asio::connect(s, resolver.resolve(argv[1], argv[2]));
+
+    std::cout << "Enter message: ";
+    char request[max_length];
+    std::cin.getline(request, max_length);
+    size_t request_length = std::strlen(request);
+    boost::asio::write(s, boost::asio::buffer(request, request_length));
+
+    char reply[max_length];
+    size_t reply_length = boost::asio::read(s,
+        boost::asio::buffer(reply, request_length));
+    std::cout << "Reply is: ";
+    std::cout.write(reply, reply_length);
+    std::cout << "\n";
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/echo/blocking_tcp_echo_server.cpp

@@ -0,0 +1,74 @@
+//
+// blocking_tcp_echo_server.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <iostream>
+#include <thread>
+#include <utility>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::tcp;
+
+const int max_length = 1024;
+
+void session(tcp::socket sock)
+{
+  try
+  {
+    for (;;)
+    {
+      char data[max_length];
+
+      boost::system::error_code error;
+      size_t length = sock.read_some(boost::asio::buffer(data), error);
+      if (error == boost::asio::error::eof)
+        break; // Connection closed cleanly by peer.
+      else if (error)
+        throw boost::system::system_error(error); // Some other error.
+
+      boost::asio::write(sock, boost::asio::buffer(data, length));
+    }
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception in thread: " << e.what() << "\n";
+  }
+}
+
+void server(boost::asio::io_context& io_context, unsigned short port)
+{
+  tcp::acceptor a(io_context, tcp::endpoint(tcp::v4(), port));
+  for (;;)
+  {
+    std::thread(session, a.accept()).detach();
+  }
+}
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: blocking_tcp_echo_server <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    server(io_context, std::atoi(argv[1]));
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/echo/blocking_udp_echo_client.cpp

@@ -0,0 +1,58 @@
+//
+// blocking_udp_echo_client.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::udp;
+
+enum { max_length = 1024 };
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 3)
+    {
+      std::cerr << "Usage: blocking_udp_echo_client <host> <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    udp::socket s(io_context, udp::endpoint(udp::v4(), 0));
+
+    udp::resolver resolver(io_context);
+    udp::resolver::results_type endpoints =
+      resolver.resolve(udp::v4(), argv[1], argv[2]);
+
+    std::cout << "Enter message: ";
+    char request[max_length];
+    std::cin.getline(request, max_length);
+    size_t request_length = std::strlen(request);
+    s.send_to(boost::asio::buffer(request, request_length), *endpoints.begin());
+
+    char reply[max_length];
+    udp::endpoint sender_endpoint;
+    size_t reply_length = s.receive_from(
+        boost::asio::buffer(reply, max_length), sender_endpoint);
+    std::cout << "Reply is: ";
+    std::cout.write(reply, reply_length);
+    std::cout << "\n";
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/echo/blocking_udp_echo_server.cpp

@@ -0,0 +1,52 @@
+//
+// blocking_udp_echo_server.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <iostream>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::udp;
+
+enum { max_length = 1024 };
+
+void server(boost::asio::io_context& io_context, unsigned short port)
+{
+  udp::socket sock(io_context, udp::endpoint(udp::v4(), port));
+  for (;;)
+  {
+    char data[max_length];
+    udp::endpoint sender_endpoint;
+    size_t length = sock.receive_from(
+        boost::asio::buffer(data, max_length), sender_endpoint);
+    sock.send_to(boost::asio::buffer(data, length), sender_endpoint);
+  }
+}
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: blocking_udp_echo_server <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    server(io_context, std::atoi(argv[1]));
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/executors/Jamfile.v2

@@ -0,0 +1,50 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+project
+  : requirements
+    <library>/boost/system//boost_system
+    <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe actor : actor.cpp ;
+exe bank_account_1 : bank_account_1.cpp ;
+exe bank_account_2 : bank_account_2.cpp ;
+exe fork_join : fork_join.cpp ;
+exe pipeline : pipeline.cpp ;
+exe priority_scheduler : priority_scheduler.cpp ;

libs/asio/example/cpp11/executors/actor.cpp

@@ -0,0 +1,286 @@
+#include <boost/asio/defer.hpp>
+#include <boost/asio/executor.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/asio/strand.hpp>
+#include <boost/asio/system_executor.hpp>
+#include <condition_variable>
+#include <deque>
+#include <memory>
+#include <mutex>
+#include <typeinfo>
+#include <vector>
+
+using boost::asio::defer;
+using boost::asio::executor;
+using boost::asio::post;
+using boost::asio::strand;
+using boost::asio::system_executor;
+
+//------------------------------------------------------------------------------
+// A tiny actor framework
+// ~~~~~~~~~~~~~~~~~~~~~~
+
+class actor;
+
+// Used to identify the sender and recipient of messages.
+typedef actor* actor_address;
+
+// Base class for all registered message handlers.
+class message_handler_base
+{
+public:
+  virtual ~message_handler_base() {}
+
+  // Used to determine which message handlers receive an incoming message.
+  virtual const std::type_info& message_id() const = 0;
+};
+
+// Base class for a handler for a specific message type.
+template <class Message>
+class message_handler : public message_handler_base
+{
+public:
+  // Handle an incoming message.
+  virtual void handle_message(Message msg, actor_address from) = 0;
+};
+
+// Concrete message handler for a specific message type.
+template <class Actor, class Message>
+class mf_message_handler : public message_handler<Message>
+{
+public:
+  // Construct a message handler to invoke the specified member function.
+  mf_message_handler(void (Actor::* mf)(Message, actor_address), Actor* a)
+    : function_(mf), actor_(a)
+  {
+  }
+
+  // Used to determine which message handlers receive an incoming message.
+  virtual const std::type_info& message_id() const
+  {
+    return typeid(Message);
+  }
+
+  // Handle an incoming message.
+  virtual void handle_message(Message msg, actor_address from)
+  {
+    (actor_->*function_)(std::move(msg), from);
+  }
+
+  // Determine whether the message handler represents the specified function.
+  bool is_function(void (Actor::* mf)(Message, actor_address)) const
+  {
+    return mf == function_;
+  }
+
+private:
+  void (Actor::* function_)(Message, actor_address);
+  Actor* actor_;
+};
+
+// Base class for all actors.
+class actor
+{
+public:
+  virtual ~actor()
+  {
+  }
+
+  // Obtain the actor's address for use as a message sender or recipient.
+  actor_address address()
+  {
+    return this;
+  }
+
+  // Send a message from one actor to another.
+  template <class Message>
+  friend void send(Message msg, actor_address from, actor_address to)
+  {
+    // Execute the message handler in the context of the target's executor.
+    post(to->executor_,
+      [=]
+      {
+        to->call_handler(std::move(msg), from);
+      });
+  }
+
+protected:
+  // Construct the actor to use the specified executor for all message handlers.
+  actor(executor e)
+    : executor_(std::move(e))
+  {
+  }
+
+  // Register a handler for a specific message type. Duplicates are permitted.
+  template <class Actor, class Message>
+  void register_handler(void (Actor::* mf)(Message, actor_address))
+  {
+    handlers_.push_back(
+      std::make_shared<mf_message_handler<Actor, Message>>(
+        mf, static_cast<Actor*>(this)));
+  }
+
+  // Deregister a handler. Removes only the first matching handler.
+  template <class Actor, class Message>
+  void deregister_handler(void (Actor::* mf)(Message, actor_address))
+  {
+    const std::type_info& id = typeid(message_handler<Message>);
+    for (auto iter = handlers_.begin(); iter != handlers_.end(); ++iter)
+    {
+      if ((*iter)->message_id() == id)
+      {
+        auto mh = static_cast<mf_message_handler<Actor, Message>*>(iter->get());
+        if (mh->is_function(mf))
+        {
+          handlers_.erase(iter);
+          return;
+        }
+      }
+    }
+  }
+
+  // Send a message from within a message handler.
+  template <class Message>
+  void tail_send(Message msg, actor_address to)
+  {
+    // Execute the message handler in the context of the target's executor.
+    actor* from = this;
+    defer(to->executor_,
+      [=]
+      {
+        to->call_handler(std::move(msg), from);
+      });
+  }
+
+private:
+  // Find the matching message handlers, if any, and call them.
+  template <class Message>
+  void call_handler(Message msg, actor_address from)
+  {
+    const std::type_info& message_id = typeid(Message);
+    for (auto& h: handlers_)
+    {
+      if (h->message_id() == message_id)
+      {
+        auto mh = static_cast<message_handler<Message>*>(h.get());
+        mh->handle_message(msg, from);
+      }
+    }
+  }
+
+  // All messages associated with a single actor object should be processed
+  // non-concurrently. We use a strand to ensure non-concurrent execution even
+  // if the underlying executor may use multiple threads.
+  strand<executor> executor_;
+
+  std::vector<std::shared_ptr<message_handler_base>> handlers_;
+};
+
+// A concrete actor that allows synchronous message retrieval.
+template <class Message>
+class receiver : public actor
+{
+public:
+  receiver()
+    : actor(system_executor())
+  {
+    register_handler(&receiver::message_handler);
+  }
+
+  // Block until a message has been received.
+  Message wait()
+  {
+    std::unique_lock<std::mutex> lock(mutex_);
+    condition_.wait(lock, [this]{ return !message_queue_.empty(); });
+    Message msg(std::move(message_queue_.front()));
+    message_queue_.pop_front();
+    return msg;
+  }
+
+private:
+  // Handle a new message by adding it to the queue and waking a waiter.
+  void message_handler(Message msg, actor_address /* from */)
+  {
+    std::lock_guard<std::mutex> lock(mutex_);
+    message_queue_.push_back(std::move(msg));
+    condition_.notify_one();
+  }
+
+  std::mutex mutex_;
+  std::condition_variable condition_;
+  std::deque<Message> message_queue_;
+};
+
+//------------------------------------------------------------------------------
+
+#include <boost/asio/thread_pool.hpp>
+#include <iostream>
+
+using boost::asio::thread_pool;
+
+class member : public actor
+{
+public:
+  explicit member(executor e)
+    : actor(std::move(e))
+  {
+    register_handler(&member::init_handler);
+  }
+
+private:
+  void init_handler(actor_address next, actor_address from)
+  {
+    next_ = next;
+    caller_ = from;
+
+    register_handler(&member::token_handler);
+    deregister_handler(&member::init_handler);
+  }
+
+  void token_handler(int token, actor_address /*from*/)
+  {
+    int msg(token);
+    actor_address to(caller_);
+
+    if (token > 0)
+    {
+      msg = token - 1;
+      to = next_;
+    }
+
+    tail_send(msg, to);
+  }
+
+  actor_address next_;
+  actor_address caller_;
+};
+
+int main()
+{
+  const std::size_t num_threads = 16;
+  const int num_hops = 50000000;
+  const std::size_t num_actors = 503;
+  const int token_value = (num_hops + num_actors - 1) / num_actors;
+  const std::size_t actors_per_thread = num_actors / num_threads;
+
+  struct single_thread_pool : thread_pool { single_thread_pool() : thread_pool(1) {} };
+  single_thread_pool pools[num_threads];
+  std::vector<std::shared_ptr<member>> members(num_actors);
+  receiver<int> rcvr;
+
+  // Create the member actors.
+  for (std::size_t i = 0; i < num_actors; ++i)
+    members[i] = std::make_shared<member>(pools[(i / actors_per_thread) % num_threads].get_executor());
+
+  // Initialise the actors by passing each one the address of the next actor in the ring.
+  for (std::size_t i = num_actors, next_i = 0; i > 0; next_i = --i)
+    send(members[next_i]->address(), rcvr.address(), members[i - 1]->address());
+
+  // Send exactly one token to each actor, all with the same initial value, rounding up if required.
+  for (std::size_t i = 0; i < num_actors; ++i)
+    send(token_value, rcvr.address(), members[i]->address());
+
+  // Wait for all signal messages, indicating the tokens have all reached zero.
+  for (std::size_t i = 0; i < num_actors; ++i)
+    rcvr.wait();
+}

libs/asio/example/cpp11/executors/bank_account_1.cpp

@@ -0,0 +1,54 @@
+#include <boost/asio/post.hpp>
+#include <boost/asio/thread_pool.hpp>
+#include <iostream>
+
+using boost::asio::post;
+using boost::asio::thread_pool;
+
+// Traditional active object pattern.
+// Member functions do not block.
+
+class bank_account
+{
+  int balance_ = 0;
+  mutable thread_pool pool_{1};
+
+public:
+  void deposit(int amount)
+  {
+    post(pool_, [=]
+      {
+        balance_ += amount;
+      });
+  }
+
+  void withdraw(int amount)
+  {
+    post(pool_, [=]
+      {
+        if (balance_ >= amount)
+          balance_ -= amount;
+      });
+  }
+
+  void print_balance() const
+  {
+    post(pool_, [=]
+      {
+        std::cout << "balance = " << balance_ << "\n";
+      });
+  }
+
+  ~bank_account()
+  {
+    pool_.join();
+  }
+};
+
+int main()
+{
+  bank_account acct;
+  acct.deposit(20);
+  acct.withdraw(10);
+  acct.print_balance();
+}

libs/asio/example/cpp11/executors/bank_account_2.cpp

@@ -0,0 +1,54 @@
+#include <boost/asio/post.hpp>
+#include <boost/asio/thread_pool.hpp>
+#include <boost/asio/use_future.hpp>
+#include <iostream>
+
+using boost::asio::post;
+using boost::asio::thread_pool;
+using boost::asio::use_future;
+
+// Traditional active object pattern.
+// Member functions block until operation is finished.
+
+class bank_account
+{
+  int balance_ = 0;
+  mutable thread_pool pool_{1};
+
+public:
+  void deposit(int amount)
+  {
+    post(pool_,
+      use_future([=]
+        {
+          balance_ += amount;
+        })).get();
+  }
+
+  void withdraw(int amount)
+  {
+    post(pool_,
+      use_future([=]
+        {
+          if (balance_ >= amount)
+            balance_ -= amount;
+        })).get();
+  }
+
+  int balance() const
+  {
+    return post(pool_,
+      use_future([=]
+        {
+          return balance_;
+        })).get();
+  }
+};
+
+int main()
+{
+  bank_account acct;
+  acct.deposit(20);
+  acct.withdraw(10);
+  std::cout << "balance = " << acct.balance() << "\n";
+}

libs/asio/example/cpp11/executors/fork_join.cpp

@@ -0,0 +1,327 @@
+#include <boost/asio/dispatch.hpp>
+#include <boost/asio/execution_context.hpp>
+#include <boost/asio/thread_pool.hpp>
+#include <condition_variable>
+#include <memory>
+#include <mutex>
+#include <queue>
+#include <thread>
+
+using boost::asio::dispatch;
+using boost::asio::execution_context;
+using boost::asio::thread_pool;
+
+// A fixed-size thread pool used to implement fork/join semantics. Functions
+// are scheduled using a simple FIFO queue. Implementing work stealing, or
+// using a queue based on atomic operations, are left as tasks for the reader.
+class fork_join_pool : public execution_context
+{
+public:
+  // The constructor starts a thread pool with the specified number of threads.
+  // Note that the thread_count is not a fixed limit on the pool's concurrency.
+  // Additional threads may temporarily be added to the pool if they join a
+  // fork_executor.
+  explicit fork_join_pool(
+      std::size_t thread_count = std::thread::hardware_concurrency() * 2)
+    : use_count_(1),
+      threads_(thread_count)
+  {
+    try
+    {
+      // Ask each thread in the pool to dequeue and execute functions until
+      // it is time to shut down, i.e. the use count is zero.
+      for (thread_count_ = 0; thread_count_ < thread_count; ++thread_count_)
+      {
+        dispatch(threads_, [&]
+            {
+              std::unique_lock<std::mutex> lock(mutex_);
+              while (use_count_ > 0)
+                if (!execute_next(lock))
+                  condition_.wait(lock);
+            });
+      }
+    }
+    catch (...)
+    {
+      stop_threads();
+      threads_.join();
+      throw;
+    }
+  }
+
+  // The destructor waits for the pool to finish executing functions.
+  ~fork_join_pool()
+  {
+    stop_threads();
+    threads_.join();
+  }
+
+private:
+  friend class fork_executor;
+
+  // The base for all functions that are queued in the pool.
+  struct function_base
+  {
+    std::shared_ptr<std::size_t> work_count_;
+    void (*execute_)(std::shared_ptr<function_base>& p);
+  };
+
+  // Execute the next function from the queue, if any. Returns true if a
+  // function was executed, and false if the queue was empty.
+  bool execute_next(std::unique_lock<std::mutex>& lock)
+  {
+    if (queue_.empty())
+      return false;
+    auto p(queue_.front());
+    queue_.pop();
+    lock.unlock();
+    execute(lock, p); 
+    return true;
+  }
+
+  // Execute a function and decrement the outstanding work.
+  void execute(std::unique_lock<std::mutex>& lock,
+      std::shared_ptr<function_base>& p)
+  {
+    std::shared_ptr<std::size_t> work_count(std::move(p->work_count_));
+    try
+    {
+      p->execute_(p);
+      lock.lock();
+      do_work_finished(work_count);
+    }
+    catch (...)
+    {
+      lock.lock();
+      do_work_finished(work_count);
+      throw;
+    }
+  }
+
+  // Increment outstanding work.
+  void do_work_started(const std::shared_ptr<std::size_t>& work_count) noexcept
+  {
+    if (++(*work_count) == 1)
+      ++use_count_;
+  }
+
+  // Decrement outstanding work. Notify waiting threads if we run out.
+  void do_work_finished(const std::shared_ptr<std::size_t>& work_count) noexcept
+  {
+    if (--(*work_count) == 0)
+    {
+      --use_count_;
+      condition_.notify_all();
+    }
+  }
+
+  // Dispatch a function, executing it immediately if the queue is already
+  // loaded. Otherwise adds the function to the queue and wakes a thread.
+  void do_dispatch(std::shared_ptr<function_base> p,
+      const std::shared_ptr<std::size_t>& work_count)
+  {
+    std::unique_lock<std::mutex> lock(mutex_);
+    if (queue_.size() > thread_count_ * 16)
+    {
+      do_work_started(work_count);
+      lock.unlock();
+      execute(lock, p);
+    }
+    else
+    {
+      queue_.push(p);
+      do_work_started(work_count);
+      condition_.notify_one();
+    }
+  }
+
+  // Add a function to the queue and wake a thread.
+  void do_post(std::shared_ptr<function_base> p,
+      const std::shared_ptr<std::size_t>& work_count)
+  {
+    std::lock_guard<std::mutex> lock(mutex_);
+    queue_.push(p);
+    do_work_started(work_count);
+    condition_.notify_one();
+  }
+
+  // Ask all threads to shut down.
+  void stop_threads()
+  {
+    std::lock_guard<std::mutex> lock(mutex_);
+    --use_count_;
+    condition_.notify_all();
+  }
+
+  std::mutex mutex_;
+  std::condition_variable condition_;
+  std::queue<std::shared_ptr<function_base>> queue_;
+  std::size_t use_count_;
+  std::size_t thread_count_;
+  thread_pool threads_;
+};
+
+// A class that satisfies the Executor requirements. Every function or piece of
+// work associated with a fork_executor is part of a single, joinable group.
+class fork_executor
+{
+public:
+  fork_executor(fork_join_pool& ctx)
+    : context_(ctx),
+      work_count_(std::make_shared<std::size_t>(0))
+  {
+  }
+
+  fork_join_pool& context() const noexcept
+  {
+    return context_;
+  }
+
+  void on_work_started() const noexcept
+  {
+    std::lock_guard<std::mutex> lock(context_.mutex_);
+    context_.do_work_started(work_count_);
+  }
+
+  void on_work_finished() const noexcept
+  {
+    std::lock_guard<std::mutex> lock(context_.mutex_);
+    context_.do_work_finished(work_count_);
+  }
+
+  template <class Func, class Alloc>
+  void dispatch(Func&& f, const Alloc& a) const
+  {
+    auto p(std::allocate_shared<function<Func>>(
+          typename std::allocator_traits<Alloc>::template rebind_alloc<char>(a),
+          std::move(f), work_count_));
+    context_.do_dispatch(p, work_count_);
+  }
+
+  template <class Func, class Alloc>
+  void post(Func f, const Alloc& a) const
+  {
+    auto p(std::allocate_shared<function<Func>>(
+          typename std::allocator_traits<Alloc>::template rebind_alloc<char>(a),
+          std::move(f), work_count_));
+    context_.do_post(p, work_count_);
+  }
+
+  template <class Func, class Alloc>
+  void defer(Func&& f, const Alloc& a) const
+  {
+    post(std::forward<Func>(f), a);
+  }
+
+  friend bool operator==(const fork_executor& a,
+      const fork_executor& b) noexcept
+  {
+    return a.work_count_ == b.work_count_;
+  }
+
+  friend bool operator!=(const fork_executor& a,
+      const fork_executor& b) noexcept
+  {
+    return a.work_count_ != b.work_count_;
+  }
+
+  // Block until all work associated with the executor is complete. While it is
+  // waiting, the thread may be borrowed to execute functions from the queue.
+  void join() const
+  {
+    std::unique_lock<std::mutex> lock(context_.mutex_);
+    while (*work_count_ > 0)
+      if (!context_.execute_next(lock))
+        context_.condition_.wait(lock);
+  }
+
+private:
+  template <class Func>
+  struct function : fork_join_pool::function_base
+  {
+    explicit function(Func f, const std::shared_ptr<std::size_t>& w)
+      : function_(std::move(f))
+    {
+      work_count_ = w;
+      execute_ = [](std::shared_ptr<fork_join_pool::function_base>& p)
+      {
+        Func tmp(std::move(static_cast<function*>(p.get())->function_));
+        p.reset();
+        tmp();
+      };
+    }
+
+    Func function_;
+  };
+
+  fork_join_pool& context_;
+  std::shared_ptr<std::size_t> work_count_;
+};
+
+// Helper class to automatically join a fork_executor when exiting a scope.
+class join_guard
+{
+public:
+  explicit join_guard(const fork_executor& ex) : ex_(ex) {}
+  join_guard(const join_guard&) = delete;
+  join_guard(join_guard&&) = delete;
+  ~join_guard() { ex_.join(); }
+
+private:
+  fork_executor ex_;
+};
+
+//------------------------------------------------------------------------------
+
+#include <algorithm>
+#include <iostream>
+#include <random>
+#include <vector>
+
+fork_join_pool pool;
+
+template <class Iterator>
+void fork_join_sort(Iterator begin, Iterator end)
+{
+  std::size_t n = end - begin;
+  if (n > 32768)
+  {
+    {
+      fork_executor fork(pool);
+      join_guard join(fork);
+      dispatch(fork, [=]{ fork_join_sort(begin, begin + n / 2); });
+      dispatch(fork, [=]{ fork_join_sort(begin + n / 2, end); });
+    }
+    std::inplace_merge(begin, begin + n / 2, end);
+  }
+  else
+  {
+    std::sort(begin, end);
+  }
+}
+
+int main(int argc, char* argv[])
+{
+  if (argc != 2)
+  {
+    std::cerr << "Usage: fork_join <size>\n";
+    return 1;
+  }
+
+  std::vector<double> vec(std::atoll(argv[1]));
+  std::iota(vec.begin(), vec.end(), 0);
+
+  std::random_device rd;
+  std::mt19937 g(rd());
+  std::shuffle(vec.begin(), vec.end(), g);
+
+  std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
+
+  fork_join_sort(vec.begin(), vec.end());
+
+  std::chrono::steady_clock::duration elapsed = std::chrono::steady_clock::now() - start;
+
+  std::cout << "sort took ";
+  std::cout << std::chrono::duration_cast<std::chrono::microseconds>(elapsed).count();
+  std::cout << " microseconds" << std::endl;
+}

libs/asio/example/cpp11/executors/pipeline.cpp

@@ -0,0 +1,298 @@
+#include <boost/asio/associated_executor.hpp>
+#include <boost/asio/bind_executor.hpp>
+#include <boost/asio/execution_context.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/asio/system_executor.hpp>
+#include <boost/asio/use_future.hpp>
+#include <condition_variable>
+#include <future>
+#include <memory>
+#include <mutex>
+#include <queue>
+#include <thread>
+#include <vector>
+
+using boost::asio::execution_context;
+using boost::asio::executor_binder;
+using boost::asio::get_associated_executor;
+using boost::asio::post;
+using boost::asio::system_executor;
+using boost::asio::use_future;
+using boost::asio::use_service;
+
+// An executor that launches a new thread for each function submitted to it.
+// This class satisfies the Executor requirements.
+class thread_executor
+{
+private:
+  // Service to track all threads started through a thread_executor.
+  class thread_bag : public execution_context::service
+  {
+  public:
+    typedef thread_bag key_type;
+
+    explicit thread_bag(execution_context& ctx)
+      : execution_context::service(ctx)
+    {
+    }
+
+    void add_thread(std::thread&& t)
+    {
+      std::unique_lock<std::mutex> lock(mutex_);
+      threads_.push_back(std::move(t));
+    }
+
+  private:
+    virtual void shutdown()
+    {
+      for (auto& t : threads_)
+        t.join();
+    }
+
+    std::mutex mutex_;
+    std::vector<std::thread> threads_;
+  };
+
+public:
+  execution_context& context() const noexcept
+  {
+    return system_executor().context();
+  }
+
+  void on_work_started() const noexcept
+  {
+    // This executor doesn't count work.
+  }
+
+  void on_work_finished() const noexcept
+  {
+    // This executor doesn't count work.
+  }
+
+  template <class Func, class Alloc>
+  void dispatch(Func&& f, const Alloc& a) const
+  {
+    post(std::forward<Func>(f), a);
+  }
+
+  template <class Func, class Alloc>
+  void post(Func f, const Alloc&) const
+  {
+    thread_bag& bag = use_service<thread_bag>(context());
+    bag.add_thread(std::thread(std::move(f)));
+  }
+
+  template <class Func, class Alloc>
+  void defer(Func&& f, const Alloc& a) const
+  {
+    post(std::forward<Func>(f), a);
+  }
+
+  friend bool operator==(const thread_executor&,
+      const thread_executor&) noexcept
+  {
+    return true;
+  }
+
+  friend bool operator!=(const thread_executor&,
+      const thread_executor&) noexcept
+  {
+    return false;
+  }
+};
+
+// Base class for all thread-safe queue implementations.
+class queue_impl_base
+{
+  template <class> friend class queue_front;
+  template <class> friend class queue_back;
+  std::mutex mutex_;
+  std::condition_variable condition_;
+  bool stop_ = false;
+};
+
+// Underlying implementation of a thread-safe queue, shared between the
+// queue_front and queue_back classes.
+template <class T>
+class queue_impl : public queue_impl_base
+{
+  template <class> friend class queue_front;
+  template <class> friend class queue_back;
+  std::queue<T> queue_;
+};
+
+// The front end of a queue between consecutive pipeline stages.
+template <class T>
+class queue_front
+{
+public:
+  typedef T value_type;
+
+  explicit queue_front(std::shared_ptr<queue_impl<T>> impl)
+    : impl_(impl)
+  {
+  }
+
+  void push(T t)
+  {
+    std::unique_lock<std::mutex> lock(impl_->mutex_);
+    impl_->queue_.push(std::move(t));
+    impl_->condition_.notify_one();
+  }
+
+  void stop()
+  {
+    std::unique_lock<std::mutex> lock(impl_->mutex_);
+    impl_->stop_ = true;
+    impl_->condition_.notify_one();
+  }
+
+private:
+  std::shared_ptr<queue_impl<T>> impl_;
+};
+
+// The back end of a queue between consecutive pipeline stages.
+template <class T>
+class queue_back
+{
+public:
+  typedef T value_type;
+
+  explicit queue_back(std::shared_ptr<queue_impl<T>> impl)
+    : impl_(impl)
+  {
+  }
+
+  bool pop(T& t)
+  {
+    std::unique_lock<std::mutex> lock(impl_->mutex_);
+    while (impl_->queue_.empty() && !impl_->stop_)
+      impl_->condition_.wait(lock);
+    if (!impl_->queue_.empty())
+    {
+      t = impl_->queue_.front();
+      impl_->queue_.pop();
+      return true;
+    }
+    return false;
+  }
+
+private:
+  std::shared_ptr<queue_impl<T>> impl_;
+};
+
+// Launch the last stage in a pipeline.
+template <class T, class F>
+std::future<void> pipeline(queue_back<T> in, F f)
+{
+  // Get the function's associated executor, defaulting to thread_executor.
+  auto ex = get_associated_executor(f, thread_executor());
+
+  // Run the function, and as we're the last stage return a future so that the
+  // caller can wait for the pipeline to finish.
+  return post(ex, use_future([in, f]() mutable { f(in); }));
+}
+
+// Launch an intermediate stage in a pipeline.
+template <class T, class F, class... Tail>
+std::future<void> pipeline(queue_back<T> in, F f, Tail... t)
+{
+  // Determine the output queue type.
+  typedef typename executor_binder<F, thread_executor>::second_argument_type::value_type output_value_type;
+
+  // Create the output queue and its implementation.
+  auto out_impl = std::make_shared<queue_impl<output_value_type>>();
+  queue_front<output_value_type> out(out_impl);
+  queue_back<output_value_type> next_in(out_impl);
+
+  // Get the function's associated executor, defaulting to thread_executor.
+  auto ex = get_associated_executor(f, thread_executor());
+
+  // Run the function.
+  post(ex, [in, out, f]() mutable
+      {
+        f(in, out);
+        out.stop();
+      });
+
+  // Launch the rest of the pipeline.
+  return pipeline(next_in, std::move(t)...);
+}
+
+// Launch the first stage in a pipeline.
+template <class F, class... Tail>
+std::future<void> pipeline(F f, Tail... t)
+{
+  // Determine the output queue type.
+  typedef typename executor_binder<F, thread_executor>::argument_type::value_type output_value_type;
+
+  // Create the output queue and its implementation.
+  auto out_impl = std::make_shared<queue_impl<output_value_type>>();
+  queue_front<output_value_type> out(out_impl);
+  queue_back<output_value_type> next_in(out_impl);
+
+  // Get the function's associated executor, defaulting to thread_executor.
+  auto ex = get_associated_executor(f, thread_executor());
+
+  // Run the function.
+  post(ex, [out, f]() mutable
+      {
+        f(out);
+        out.stop();
+      });
+
+  // Launch the rest of the pipeline.
+  return pipeline(next_in, std::move(t)...);
+}
+
+//------------------------------------------------------------------------------
+
+#include <boost/asio/thread_pool.hpp>
+#include <iostream>
+#include <string>
+
+using boost::asio::bind_executor;
+using boost::asio::thread_pool;
+
+void reader(queue_front<std::string> out)
+{
+  std::string line;
+  while (std::getline(std::cin, line))
+    out.push(line);
+}
+
+void filter(queue_back<std::string> in, queue_front<std::string> out)
+{
+  std::string line;
+  while (in.pop(line))
+    if (line.length() > 5)
+      out.push(line);
+}
+
+void upper(queue_back<std::string> in, queue_front<std::string> out)
+{
+  std::string line;
+  while (in.pop(line))
+  {
+    std::string new_line;
+    for (char c : line)
+      new_line.push_back(std::toupper(c));
+    out.push(new_line);
+  }
+}
+
+void writer(queue_back<std::string> in)
+{
+  std::size_t count = 0;
+  std::string line;
+  while (in.pop(line))
+    std::cout << count++ << ": " << line << std::endl;
+}
+
+int main()
+{
+  thread_pool pool;
+
+  auto f = pipeline(reader, filter, bind_executor(pool, upper), writer);
+  f.wait();
+}

libs/asio/example/cpp11/executors/priority_scheduler.cpp

@@ -0,0 +1,168 @@
+#include <boost/asio/dispatch.hpp>
+#include <boost/asio/execution_context.hpp>
+#include <condition_variable>
+#include <iostream>
+#include <memory>
+#include <mutex>
+#include <queue>
+
+using boost::asio::dispatch;
+using boost::asio::execution_context;
+
+class priority_scheduler : public execution_context
+{
+public:
+  // A class that satisfies the Executor requirements.
+  class executor_type
+  {
+  public:
+    executor_type(priority_scheduler& ctx, int pri) noexcept
+      : context_(ctx), priority_(pri)
+    {
+    }
+
+    priority_scheduler& context() const noexcept
+    {
+      return context_;
+    }
+
+    void on_work_started() const noexcept
+    {
+      // This executor doesn't count work. Instead, the scheduler simply runs
+      // until explicitly stopped.
+    }
+
+    void on_work_finished() const noexcept
+    {
+      // This executor doesn't count work. Instead, the scheduler simply runs
+      // until explicitly stopped.
+    }
+
+    template <class Func, class Alloc>
+    void dispatch(Func&& f, const Alloc& a) const
+    {
+      post(std::forward<Func>(f), a);
+    }
+
+    template <class Func, class Alloc>
+    void post(Func f, const Alloc& a) const
+    {
+      auto p(std::allocate_shared<item<Func>>(
+            typename std::allocator_traits<
+              Alloc>::template rebind_alloc<char>(a),
+            priority_, std::move(f)));
+      std::lock_guard<std::mutex> lock(context_.mutex_);
+      context_.queue_.push(p);
+      context_.condition_.notify_one();
+    }
+
+    template <class Func, class Alloc>
+    void defer(Func&& f, const Alloc& a) const
+    {
+      post(std::forward<Func>(f), a);
+    }
+
+    friend bool operator==(const executor_type& a,
+        const executor_type& b) noexcept
+    {
+      return &a.context_ == &b.context_;
+    }
+
+    friend bool operator!=(const executor_type& a,
+        const executor_type& b) noexcept
+    {
+      return &a.context_ != &b.context_;
+    }
+
+  private:
+    priority_scheduler& context_;
+    int priority_;
+  };
+
+  executor_type get_executor(int pri = 0) noexcept
+  {
+    return executor_type(*const_cast<priority_scheduler*>(this), pri);
+  }
+
+  void run()
+  {
+    std::unique_lock<std::mutex> lock(mutex_);
+    for (;;)
+    {
+      condition_.wait(lock, [&]{ return stopped_ || !queue_.empty(); });
+      if (stopped_)
+        return;
+      auto p(queue_.top());
+      queue_.pop();
+      lock.unlock();
+      p->execute_(p);
+      lock.lock();
+    }
+  }
+
+  void stop()
+  {
+    std::lock_guard<std::mutex> lock(mutex_);
+    stopped_ = true;
+    condition_.notify_all();
+  }
+
+private:
+  struct item_base
+  {
+    int priority_;
+    void (*execute_)(std::shared_ptr<item_base>&);
+  };
+
+  template <class Func>
+  struct item : item_base
+  {
+    item(int pri, Func f) : function_(std::move(f))
+    {
+      priority_ = pri;
+      execute_ = [](std::shared_ptr<item_base>& p)
+      {
+        Func tmp(std::move(static_cast<item*>(p.get())->function_));
+        p.reset();
+        tmp();
+      };
+    }
+
+    Func function_;
+  };
+
+  struct item_comp
+  {
+    bool operator()(
+        const std::shared_ptr<item_base>& a,
+        const std::shared_ptr<item_base>& b)
+    {
+      return a->priority_ < b->priority_;
+    }
+  };
+
+  std::mutex mutex_;
+  std::condition_variable condition_;
+  std::priority_queue<
+    std::shared_ptr<item_base>,
+    std::vector<std::shared_ptr<item_base>>,
+    item_comp> queue_;
+  bool stopped_ = false;
+};
+
+int main()
+{
+  priority_scheduler sched;
+  auto low = sched.get_executor(0);
+  auto med = sched.get_executor(1);
+  auto high = sched.get_executor(2);
+  dispatch(low, []{ std::cout << "1\n"; });
+  dispatch(low, []{ std::cout << "11\n"; });
+  dispatch(med, []{ std::cout << "2\n"; });
+  dispatch(med, []{ std::cout << "22\n"; });
+  dispatch(high, []{ std::cout << "3\n"; });
+  dispatch(high, []{ std::cout << "33\n"; });
+  dispatch(high, []{ std::cout << "333\n"; });
+  dispatch(sched.get_executor(-1), [&]{ sched.stop(); });
+  sched.run();
+}

libs/asio/example/cpp11/fork/Jamfile.v2

@@ -0,0 +1,59 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe daemon
+  : daemon.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe process_per_connection
+  : process_per_connection.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/fork/daemon.cpp

@@ -0,0 +1,189 @@
+//
+// daemon.cpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/ip/udp.hpp>
+#include <boost/asio/signal_set.hpp>
+#include <array>
+#include <ctime>
+#include <iostream>
+#include <syslog.h>
+#include <unistd.h>
+
+using boost::asio::ip::udp;
+
+class udp_daytime_server
+{
+public:
+  udp_daytime_server(boost::asio::io_context& io_context)
+    : socket_(io_context, {udp::v4(), 13})
+  {
+    receive();
+  }
+
+private:
+  void receive()
+  {
+    socket_.async_receive_from(
+        boost::asio::buffer(recv_buffer_), remote_endpoint_,
+        [this](boost::system::error_code ec, std::size_t /*n*/)
+        {
+          if (!ec)
+          {
+            using namespace std; // For time_t, time and ctime;
+            time_t now = time(0);
+            std::string message = ctime(&now);
+
+            boost::system::error_code ignored_ec;
+            socket_.send_to(boost::asio::buffer(message),
+                remote_endpoint_, 0, ignored_ec);
+          }
+
+          receive();
+        });
+  }
+
+  udp::socket socket_;
+  udp::endpoint remote_endpoint_;
+  std::array<char, 1> recv_buffer_;
+};
+
+int main()
+{
+  try
+  {
+    boost::asio::io_context io_context;
+
+    // Initialise the server before becoming a daemon. If the process is
+    // started from a shell, this means any errors will be reported back to the
+    // user.
+    udp_daytime_server server(io_context);
+
+    // Register signal handlers so that the daemon may be shut down. You may
+    // also want to register for other signals, such as SIGHUP to trigger a
+    // re-read of a configuration file.
+    boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);
+    signals.async_wait(
+        [&](boost::system::error_code /*ec*/, int /*signo*/)
+        {
+          io_context.stop();
+        });
+
+    // Inform the io_context that we are about to become a daemon. The
+    // io_context cleans up any internal resources, such as threads, that may
+    // interfere with forking.
+    io_context.notify_fork(boost::asio::io_context::fork_prepare);
+
+    // Fork the process and have the parent exit. If the process was started
+    // from a shell, this returns control to the user. Forking a new process is
+    // also a prerequisite for the subsequent call to setsid().
+    if (pid_t pid = fork())
+    {
+      if (pid > 0)
+      {
+        // We're in the parent process and need to exit.
+        //
+        // When the exit() function is used, the program terminates without
+        // invoking local variables' destructors. Only global variables are
+        // destroyed. As the io_context object is a local variable, this means
+        // we do not have to call:
+        //
+        //   io_context.notify_fork(boost::asio::io_context::fork_parent);
+        //
+        // However, this line should be added before each call to exit() if
+        // using a global io_context object. An additional call:
+        //
+        //   io_context.notify_fork(boost::asio::io_context::fork_prepare);
+        //
+        // should also precede the second fork().
+        exit(0);
+      }
+      else
+      {
+        syslog(LOG_ERR | LOG_USER, "First fork failed: %m");
+        return 1;
+      }
+    }
+
+    // Make the process a new session leader. This detaches it from the
+    // terminal.
+    setsid();
+
+    // A process inherits its working directory from its parent. This could be
+    // on a mounted filesystem, which means that the running daemon would
+    // prevent this filesystem from being unmounted. Changing to the root
+    // directory avoids this problem.
+    chdir("/");
+
+    // The file mode creation mask is also inherited from the parent process.
+    // We don't want to restrict the permissions on files created by the
+    // daemon, so the mask is cleared.
+    umask(0);
+
+    // A second fork ensures the process cannot acquire a controlling terminal.
+    if (pid_t pid = fork())
+    {
+      if (pid > 0)
+      {
+        exit(0);
+      }
+      else
+      {
+        syslog(LOG_ERR | LOG_USER, "Second fork failed: %m");
+        return 1;
+      }
+    }
+
+    // Close the standard streams. This decouples the daemon from the terminal
+    // that started it.
+    close(0);
+    close(1);
+    close(2);
+
+    // We don't want the daemon to have any standard input.
+    if (open("/dev/null", O_RDONLY) < 0)
+    {
+      syslog(LOG_ERR | LOG_USER, "Unable to open /dev/null: %m");
+      return 1;
+    }
+
+    // Send standard output to a log file.
+    const char* output = "/tmp/asio.daemon.out";
+    const int flags = O_WRONLY | O_CREAT | O_APPEND;
+    const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
+    if (open(output, flags, mode) < 0)
+    {
+      syslog(LOG_ERR | LOG_USER, "Unable to open output file %s: %m", output);
+      return 1;
+    }
+
+    // Also send standard error to the same log file.
+    if (dup(1) < 0)
+    {
+      syslog(LOG_ERR | LOG_USER, "Unable to dup output descriptor: %m");
+      return 1;
+    }
+
+    // Inform the io_context that we have finished becoming a daemon. The
+    // io_context uses this opportunity to create any internal file descriptors
+    // that need to be private to the new process.
+    io_context.notify_fork(boost::asio::io_context::fork_child);
+
+    // The io_context can now be used normally.
+    syslog(LOG_INFO | LOG_USER, "Daemon started");
+    io_context.run();
+    syslog(LOG_INFO | LOG_USER, "Daemon stopped");
+  }
+  catch (std::exception& e)
+  {
+    syslog(LOG_ERR | LOG_USER, "Exception: %s", e.what());
+    std::cerr << "Exception: " << e.what() << std::endl;
+  }
+}

libs/asio/example/cpp11/fork/process_per_connection.cpp

@@ -0,0 +1,162 @@
+//
+// process_per_connection.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/signal_set.hpp>
+#include <boost/asio/write.hpp>
+#include <cstdlib>
+#include <iostream>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+using boost::asio::ip::tcp;
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, unsigned short port)
+    : io_context_(io_context),
+      signal_(io_context, SIGCHLD),
+      acceptor_(io_context, {tcp::v4(), port}),
+      socket_(io_context)
+  {
+    wait_for_signal();
+    accept();
+  }
+
+private:
+  void wait_for_signal()
+  {
+    signal_.async_wait(
+        [this](boost::system::error_code /*ec*/, int /*signo*/)
+        {
+          // Only the parent process should check for this signal. We can
+          // determine whether we are in the parent by checking if the acceptor
+          // is still open.
+          if (acceptor_.is_open())
+          {
+            // Reap completed child processes so that we don't end up with
+            // zombies.
+            int status = 0;
+            while (waitpid(-1, &status, WNOHANG) > 0) {}
+
+            wait_for_signal();
+          }
+        });
+  }
+
+  void accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, tcp::socket new_socket)
+        {
+          if (!ec)
+          {
+            // Take ownership of the newly accepted socket.
+            socket_ = std::move(new_socket);
+
+            // Inform the io_context that we are about to fork. The io_context
+            // cleans up any internal resources, such as threads, that may
+            // interfere with forking.
+            io_context_.notify_fork(boost::asio::io_context::fork_prepare);
+
+            if (fork() == 0)
+            {
+              // Inform the io_context that the fork is finished and that this
+              // is the child process. The io_context uses this opportunity to
+              // create any internal file descriptors that must be private to
+              // the new process.
+              io_context_.notify_fork(boost::asio::io_context::fork_child);
+
+              // The child won't be accepting new connections, so we can close
+              // the acceptor. It remains open in the parent.
+              acceptor_.close();
+
+              // The child process is not interested in processing the SIGCHLD
+              // signal.
+              signal_.cancel();
+
+              read();
+            }
+            else
+            {
+
+              // Inform the io_context that the fork is finished (or failed)
+              // and that this is the parent process. The io_context uses this
+              // opportunity to recreate any internal resources that were
+              // cleaned up during preparation for the fork.
+              io_context_.notify_fork(boost::asio::io_context::fork_parent);
+
+              // The parent process can now close the newly accepted socket. It
+              // remains open in the child.
+              socket_.close();
+
+              accept();
+            }
+          }
+          else
+          {
+            std::cerr << "Accept error: " << ec.message() << std::endl;
+            accept();
+          }
+        });
+  }
+
+  void read()
+  {
+    socket_.async_read_some(boost::asio::buffer(data_),
+        [this](boost::system::error_code ec, std::size_t length)
+        {
+          if (!ec)
+            write(length);
+        });
+  }
+
+  void write(std::size_t length)
+  {
+    boost::asio::async_write(socket_, boost::asio::buffer(data_, length),
+        [this](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+            read();
+        });
+  }
+
+  boost::asio::io_context& io_context_;
+  boost::asio::signal_set signal_;
+  tcp::acceptor acceptor_;
+  tcp::socket socket_;
+  std::array<char, 1024> data_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: process_per_connection <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    using namespace std; // For atoi.
+    server s(io_context, atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << std::endl;
+  }
+}

libs/asio/example/cpp11/futures/Jamfile.v2

@@ -0,0 +1,43 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe server
+  : daytime_client.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/futures/daytime_client.cpp

@@ -0,0 +1,94 @@
+//
+// daytime_client.cpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <array>
+#include <future>
+#include <iostream>
+#include <thread>
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/ip/udp.hpp>
+#include <boost/asio/use_future.hpp>
+
+using boost::asio::ip::udp;
+
+void get_daytime(boost::asio::io_context& io_context, const char* hostname)
+{
+  try
+  {
+    udp::resolver resolver(io_context);
+
+    std::future<udp::resolver::results_type> endpoints =
+      resolver.async_resolve(
+          udp::v4(), hostname, "daytime",
+          boost::asio::use_future);
+
+    // The async_resolve operation above returns the endpoints as a future
+    // value that is not retrieved ...
+
+    udp::socket socket(io_context, udp::v4());
+
+    std::array<char, 1> send_buf  = {{ 0 }};
+    std::future<std::size_t> send_length =
+      socket.async_send_to(boost::asio::buffer(send_buf),
+          *endpoints.get().begin(), // ... until here. This call may block.
+          boost::asio::use_future);
+
+    // Do other things here while the send completes.
+
+    send_length.get(); // Blocks until the send is complete. Throws any errors.
+
+    std::array<char, 128> recv_buf;
+    udp::endpoint sender_endpoint;
+    std::future<std::size_t> recv_length =
+      socket.async_receive_from(
+          boost::asio::buffer(recv_buf),
+          sender_endpoint,
+          boost::asio::use_future);
+
+    // Do other things here while the receive completes.
+
+    std::cout.write(
+        recv_buf.data(),
+        recv_length.get()); // Blocks until receive is complete.
+  }
+  catch (std::system_error& e)
+  {
+    std::cerr << e.what() << std::endl;
+  }
+}
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: daytime_client <host>" << std::endl;
+      return 1;
+    }
+
+    // We run the io_context off in its own thread so that it operates
+    // completely asynchronously with respect to the rest of the program.
+    boost::asio::io_context io_context;
+    auto work = boost::asio::make_work_guard(io_context);
+    std::thread thread([&io_context](){ io_context.run(); });
+
+    get_daytime(io_context, argv[1]);
+
+    io_context.stop();
+    thread.join();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << e.what() << std::endl;
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/handler_tracking/Jamfile.v2

@@ -0,0 +1,45 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe async_tcp_echo_server
+  : async_tcp_echo_server.cpp
+    /boost/system//boost_system
+  : <include>.
+    <define>BOOST_ALL_NO_LIB=1
+    <define>BOOST_ASIO_CUSTOM_HANDLER_TRACKING=\\\"custom_tracking.hpp\\\"
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/handler_tracking/async_tcp_echo_server.cpp

@@ -0,0 +1,114 @@
+//
+// async_tcp_echo_server.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+#include <utility>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::tcp;
+
+class session
+  : public std::enable_shared_from_this<session>
+{
+public:
+  session(tcp::socket socket)
+    : socket_(std::move(socket))
+  {
+  }
+
+  void start()
+  {
+    do_read();
+  }
+
+private:
+  void do_read()
+  {
+    auto self(shared_from_this());
+    socket_.async_read_some(boost::asio::buffer(data_, max_length),
+        [this, self](boost::system::error_code ec, std::size_t length)
+        {
+          if (!ec)
+          {
+            do_write(length);
+          }
+        });
+  }
+
+  void do_write(std::size_t length)
+  {
+    auto self(shared_from_this());
+    boost::asio::async_write(socket_, boost::asio::buffer(data_, length),
+        [this, self](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+          {
+            do_read();
+          }
+        });
+  }
+
+  tcp::socket socket_;
+  enum { max_length = 1024 };
+  char data_[max_length];
+};
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, short port)
+    : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, tcp::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<session>(std::move(socket))->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  tcp::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: async_tcp_echo_server <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    server s(io_context, std::atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/handler_tracking/custom_tracking.hpp

@@ -0,0 +1,201 @@
+//
+// custom_tracking.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef CUSTOM_TRACKING_HPP
+#define CUSTOM_TRACKING_HPP
+
+#include <cinttypes>
+#include <cstdint>
+#include <cstdio>
+
+# define BOOST_ASIO_INHERIT_TRACKED_HANDLER \
+  : public ::custom_tracking::tracked_handler
+
+# define BOOST_ASIO_ALSO_INHERIT_TRACKED_HANDLER \
+  , public ::custom_tracking::tracked_handler
+
+# define BOOST_ASIO_HANDLER_TRACKING_INIT \
+  ::custom_tracking::init()
+
+# define BOOST_ASIO_HANDLER_CREATION(args) \
+  ::custom_tracking::creation args
+
+# define BOOST_ASIO_HANDLER_COMPLETION(args) \
+  ::custom_tracking::completion tracked_completion args
+
+# define BOOST_ASIO_HANDLER_INVOCATION_BEGIN(args) \
+  tracked_completion.invocation_begin args
+
+# define BOOST_ASIO_HANDLER_INVOCATION_END \
+  tracked_completion.invocation_end()
+
+# define BOOST_ASIO_HANDLER_OPERATION(args) \
+  ::custom_tracking::operation args
+
+# define BOOST_ASIO_HANDLER_REACTOR_REGISTRATION(args) \
+  ::custom_tracking::reactor_registration args
+
+# define BOOST_ASIO_HANDLER_REACTOR_DEREGISTRATION(args) \
+  ::custom_tracking::reactor_deregistration args
+
+# define BOOST_ASIO_HANDLER_REACTOR_READ_EVENT 1
+# define BOOST_ASIO_HANDLER_REACTOR_WRITE_EVENT 2
+# define BOOST_ASIO_HANDLER_REACTOR_ERROR_EVENT 4
+
+# define BOOST_ASIO_HANDLER_REACTOR_EVENTS(args) \
+  ::custom_tracking::reactor_events args
+
+# define BOOST_ASIO_HANDLER_REACTOR_OPERATION(args) \
+  ::custom_tracking::reactor_operation args
+
+struct custom_tracking
+{
+  // Base class for objects containing tracked handlers.
+  struct tracked_handler
+  {
+    std::uintmax_t handler_id_ = 0; // To uniquely identify a handler.
+    std::uintmax_t tree_id_ = 0; // To identify related handlers.
+    const char* object_type_; // The object type associated with the handler.
+    std::uintmax_t native_handle_; // Native handle, if any.
+  };
+
+  // Initialise the tracking system.
+  static void init()
+  {
+  }
+
+  // Record the creation of a tracked handler.
+  static void creation(boost::asio::execution_context& /*ctx*/,
+      tracked_handler& h, const char* object_type, void* /*object*/,
+      std::uintmax_t native_handle, const char* op_name)
+  {
+    // Generate a unique id for the new handler.
+    static std::atomic<std::uintmax_t> next_handler_id{1};
+    h.handler_id_ = next_handler_id++;
+
+    // Copy the tree identifier forward from the current handler.
+    if (*current_completion())
+      h.tree_id_ = (*current_completion())->handler_.tree_id_;
+
+    // Store various attributes of the operation to use in later output.
+    h.object_type_ = object_type;
+    h.native_handle_ = native_handle;
+
+    std::printf(
+        "Starting operation %s.%s for native_handle = %" PRIuMAX
+        ", handler = %" PRIuMAX ", tree = %" PRIuMAX "\n",
+        object_type, op_name, h.native_handle_, h.handler_id_, h.tree_id_);
+  }
+
+  struct completion
+  {
+    explicit completion(const tracked_handler& h)
+      : handler_(h),
+        next_(*current_completion())
+    {
+      *current_completion() = this;
+    }
+
+    completion(const completion&) = delete;
+    completion& operator=(const completion&) = delete;
+
+    // Destructor records only when an exception is thrown from the handler, or
+    // if the memory is being freed without the handler having been invoked.
+    ~completion()
+    {
+      *current_completion() = next_;
+    }
+
+    // Records that handler is to be invoked with the specified arguments.
+    template <class... Args>
+    void invocation_begin(Args&&... /*args*/)
+    {
+      std::printf("Entering handler %" PRIuMAX " in tree %" PRIuMAX "\n",
+          handler_.handler_id_, handler_.tree_id_);
+    }
+
+    // Record that handler invocation has ended.
+    void invocation_end()
+    {
+      std::printf("Leaving handler %" PRIuMAX " in tree %" PRIuMAX "\n",
+          handler_.handler_id_, handler_.tree_id_);
+    }
+
+    tracked_handler handler_;
+
+    // Completions may nest. Here we stash a pointer to the outer completion.
+    completion* next_;
+  };
+
+  static completion** current_completion()
+  {
+    static BOOST_ASIO_THREAD_KEYWORD completion* current = nullptr;
+    return &current;
+  }
+
+  // Record an operation that is not directly associated with a handler.
+  static void operation(boost::asio::execution_context& /*ctx*/,
+      const char* /*object_type*/, void* /*object*/,
+      std::uintmax_t /*native_handle*/, const char* /*op_name*/)
+  {
+  }
+
+  // Record that a descriptor has been registered with the reactor.
+  static void reactor_registration(boost::asio::execution_context& context,
+      uintmax_t native_handle, uintmax_t registration)
+  {
+    std::printf("Adding to reactor native_handle = %" PRIuMAX
+        ", registration = %" PRIuMAX "\n", native_handle, registration);
+  }
+
+  // Record that a descriptor has been deregistered from the reactor.
+  static void reactor_deregistration(boost::asio::execution_context& context,
+      uintmax_t native_handle, uintmax_t registration)
+  {
+    std::printf("Removing from reactor native_handle = %" PRIuMAX
+        ", registration = %" PRIuMAX "\n", native_handle, registration);
+  }
+
+  // Record reactor-based readiness events associated with a descriptor.
+  static void reactor_events(boost::asio::execution_context& context,
+      uintmax_t registration, unsigned events)
+  {
+    std::printf(
+        "Reactor readiness for registration = %" PRIuMAX ", events =%s%s%s\n",
+        registration,
+        (events & BOOST_ASIO_HANDLER_REACTOR_READ_EVENT) ? " read" : "",
+        (events & BOOST_ASIO_HANDLER_REACTOR_WRITE_EVENT) ? " write" : "",
+        (events & BOOST_ASIO_HANDLER_REACTOR_ERROR_EVENT) ? " error" : "");
+  }
+
+  // Record a reactor-based operation that is associated with a handler.
+  static void reactor_operation(const tracked_handler& h,
+      const char* op_name, const boost::system::error_code& ec)
+  {
+    std::printf(
+        "Performed operation %s.%s for native_handle = %" PRIuMAX
+        ", ec = %s:%d\n", h.object_type_, op_name, h.native_handle_,
+        ec.category().name(), ec.value());
+  }
+
+  // Record a reactor-based operation that is associated with a handler.
+  static void reactor_operation(const tracked_handler& h,
+      const char* op_name, const boost::system::error_code& ec,
+      std::size_t bytes_transferred)
+  {
+    std::printf(
+        "Performed operation %s.%s for native_handle = %" PRIuMAX
+        ", ec = %s:%d, n = %" PRIuMAX "\n", h.object_type_, op_name,
+        h.native_handle_, ec.category().name(), ec.value(),
+        static_cast<uintmax_t>(bytes_transferred));
+  }
+};
+
+#endif // CUSTOM_TRACKING_HPP

libs/asio/example/cpp11/http/server/Jamfile.v2

@@ -0,0 +1,51 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe server
+  : connection.cpp
+    connection_manager.cpp
+    main.cpp
+    mime_types.cpp
+    reply.cpp
+    request_handler.cpp
+    request_parser.cpp
+    server.cpp
+    /boost/system//boost_system
+    /boost/thread//boost_thread
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/http/server/connection.cpp

@@ -0,0 +1,94 @@
+//
+// connection.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "connection.hpp"
+#include <utility>
+#include <vector>
+#include "connection_manager.hpp"
+#include "request_handler.hpp"
+
+namespace http {
+namespace server {
+
+connection::connection(boost::asio::ip::tcp::socket socket,
+    connection_manager& manager, request_handler& handler)
+  : socket_(std::move(socket)),
+    connection_manager_(manager),
+    request_handler_(handler)
+{
+}
+
+void connection::start()
+{
+  do_read();
+}
+
+void connection::stop()
+{
+  socket_.close();
+}
+
+void connection::do_read()
+{
+  auto self(shared_from_this());
+  socket_.async_read_some(boost::asio::buffer(buffer_),
+      [this, self](boost::system::error_code ec, std::size_t bytes_transferred)
+      {
+        if (!ec)
+        {
+          request_parser::result_type result;
+          std::tie(result, std::ignore) = request_parser_.parse(
+              request_, buffer_.data(), buffer_.data() + bytes_transferred);
+
+          if (result == request_parser::good)
+          {
+            request_handler_.handle_request(request_, reply_);
+            do_write();
+          }
+          else if (result == request_parser::bad)
+          {
+            reply_ = reply::stock_reply(reply::bad_request);
+            do_write();
+          }
+          else
+          {
+            do_read();
+          }
+        }
+        else if (ec != boost::asio::error::operation_aborted)
+        {
+          connection_manager_.stop(shared_from_this());
+        }
+      });
+}
+
+void connection::do_write()
+{
+  auto self(shared_from_this());
+  boost::asio::async_write(socket_, reply_.to_buffers(),
+      [this, self](boost::system::error_code ec, std::size_t)
+      {
+        if (!ec)
+        {
+          // Initiate graceful connection closure.
+          boost::system::error_code ignored_ec;
+          socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both,
+            ignored_ec);
+        }
+
+        if (ec != boost::asio::error::operation_aborted)
+        {
+          connection_manager_.stop(shared_from_this());
+        }
+      });
+}
+
+} // namespace server
+} // namespace http

libs/asio/example/cpp11/http/server/connection.hpp

@@ -0,0 +1,79 @@
+//
+// connection.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_CONNECTION_HPP
+#define HTTP_CONNECTION_HPP
+
+#include <array>
+#include <memory>
+#include <boost/asio.hpp>
+#include "reply.hpp"
+#include "request.hpp"
+#include "request_handler.hpp"
+#include "request_parser.hpp"
+
+namespace http {
+namespace server {
+
+class connection_manager;
+
+/// Represents a single connection from a client.
+class connection
+  : public std::enable_shared_from_this<connection>
+{
+public:
+  connection(const connection&) = delete;
+  connection& operator=(const connection&) = delete;
+
+  /// Construct a connection with the given socket.
+  explicit connection(boost::asio::ip::tcp::socket socket,
+      connection_manager& manager, request_handler& handler);
+
+  /// Start the first asynchronous operation for the connection.
+  void start();
+
+  /// Stop all asynchronous operations associated with the connection.
+  void stop();
+
+private:
+  /// Perform an asynchronous read operation.
+  void do_read();
+
+  /// Perform an asynchronous write operation.
+  void do_write();
+
+  /// Socket for the connection.
+  boost::asio::ip::tcp::socket socket_;
+
+  /// The manager for this connection.
+  connection_manager& connection_manager_;
+
+  /// The handler used to process the incoming request.
+  request_handler& request_handler_;
+
+  /// Buffer for incoming data.
+  std::array<char, 8192> buffer_;
+
+  /// The incoming request.
+  request request_;
+
+  /// The parser for the incoming request.
+  request_parser request_parser_;
+
+  /// The reply to be sent back to the client.
+  reply reply_;
+};
+
+typedef std::shared_ptr<connection> connection_ptr;
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_CONNECTION_HPP

libs/asio/example/cpp11/http/server/connection_manager.cpp

@@ -0,0 +1,40 @@
+//
+// connection_manager.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "connection_manager.hpp"
+
+namespace http {
+namespace server {
+
+connection_manager::connection_manager()
+{
+}
+
+void connection_manager::start(connection_ptr c)
+{
+  connections_.insert(c);
+  c->start();
+}
+
+void connection_manager::stop(connection_ptr c)
+{
+  connections_.erase(c);
+  c->stop();
+}
+
+void connection_manager::stop_all()
+{
+  for (auto c: connections_)
+    c->stop();
+  connections_.clear();
+}
+
+} // namespace server
+} // namespace http

libs/asio/example/cpp11/http/server/connection_manager.hpp

@@ -0,0 +1,48 @@
+//
+// connection_manager.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_CONNECTION_MANAGER_HPP
+#define HTTP_CONNECTION_MANAGER_HPP
+
+#include <set>
+#include "connection.hpp"
+
+namespace http {
+namespace server {
+
+/// Manages open connections so that they may be cleanly stopped when the server
+/// needs to shut down.
+class connection_manager
+{
+public:
+  connection_manager(const connection_manager&) = delete;
+  connection_manager& operator=(const connection_manager&) = delete;
+
+  /// Construct a connection manager.
+  connection_manager();
+
+  /// Add the specified connection to the manager and start it.
+  void start(connection_ptr c);
+
+  /// Stop the specified connection.
+  void stop(connection_ptr c);
+
+  /// Stop all connections.
+  void stop_all();
+
+private:
+  /// The managed connections.
+  std::set<connection_ptr> connections_;
+};
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_CONNECTION_MANAGER_HPP

libs/asio/example/cpp11/http/server/header.hpp

@@ -0,0 +1,28 @@
+//
+// header.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_HEADER_HPP
+#define HTTP_HEADER_HPP
+
+#include <string>
+
+namespace http {
+namespace server {
+
+struct header
+{
+  std::string name;
+  std::string value;
+};
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_HEADER_HPP

libs/asio/example/cpp11/http/server/main.cpp

@@ -0,0 +1,43 @@
+//
+// main.cpp
+// ~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <iostream>
+#include <string>
+#include <boost/asio.hpp>
+#include "server.hpp"
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    // Check command line arguments.
+    if (argc != 4)
+    {
+      std::cerr << "Usage: http_server <address> <port> <doc_root>\n";
+      std::cerr << "  For IPv4, try:\n";
+      std::cerr << "    receiver 0.0.0.0 80 .\n";
+      std::cerr << "  For IPv6, try:\n";
+      std::cerr << "    receiver 0::0 80 .\n";
+      return 1;
+    }
+
+    // Initialise the server.
+    http::server::server s(argv[1], argv[2], argv[3]);
+
+    // Run the server until stopped.
+    s.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/http/server/mime_types.cpp

@@ -0,0 +1,45 @@
+//
+// mime_types.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "mime_types.hpp"
+
+namespace http {
+namespace server {
+namespace mime_types {
+
+struct mapping
+{
+  const char* extension;
+  const char* mime_type;
+} mappings[] =
+{
+  { "gif", "image/gif" },
+  { "htm", "text/html" },
+  { "html", "text/html" },
+  { "jpg", "image/jpeg" },
+  { "png", "image/png" }
+};
+
+std::string extension_to_type(const std::string& extension)
+{
+  for (mapping m: mappings)
+  {
+    if (m.extension == extension)
+    {
+      return m.mime_type;
+    }
+  }
+
+  return "text/plain";
+}
+
+} // namespace mime_types
+} // namespace server
+} // namespace http

libs/asio/example/cpp11/http/server/mime_types.hpp

@@ -0,0 +1,27 @@
+//
+// mime_types.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_MIME_TYPES_HPP
+#define HTTP_MIME_TYPES_HPP
+
+#include <string>
+
+namespace http {
+namespace server {
+namespace mime_types {
+
+/// Convert a file extension into a MIME type.
+std::string extension_to_type(const std::string& extension);
+
+} // namespace mime_types
+} // namespace server
+} // namespace http
+
+#endif // HTTP_MIME_TYPES_HPP

libs/asio/example/cpp11/http/server/reply.cpp

@@ -0,0 +1,255 @@
+//
+// reply.cpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "reply.hpp"
+#include <string>
+
+namespace http {
+namespace server {
+
+namespace status_strings {
+
+const std::string ok =
+  "HTTP/1.0 200 OK\r\n";
+const std::string created =
+  "HTTP/1.0 201 Created\r\n";
+const std::string accepted =
+  "HTTP/1.0 202 Accepted\r\n";
+const std::string no_content =
+  "HTTP/1.0 204 No Content\r\n";
+const std::string multiple_choices =
+  "HTTP/1.0 300 Multiple Choices\r\n";
+const std::string moved_permanently =
+  "HTTP/1.0 301 Moved Permanently\r\n";
+const std::string moved_temporarily =
+  "HTTP/1.0 302 Moved Temporarily\r\n";
+const std::string not_modified =
+  "HTTP/1.0 304 Not Modified\r\n";
+const std::string bad_request =
+  "HTTP/1.0 400 Bad Request\r\n";
+const std::string unauthorized =
+  "HTTP/1.0 401 Unauthorized\r\n";
+const std::string forbidden =
+  "HTTP/1.0 403 Forbidden\r\n";
+const std::string not_found =
+  "HTTP/1.0 404 Not Found\r\n";
+const std::string internal_server_error =
+  "HTTP/1.0 500 Internal Server Error\r\n";
+const std::string not_implemented =
+  "HTTP/1.0 501 Not Implemented\r\n";
+const std::string bad_gateway =
+  "HTTP/1.0 502 Bad Gateway\r\n";
+const std::string service_unavailable =
+  "HTTP/1.0 503 Service Unavailable\r\n";
+
+boost::asio::const_buffer to_buffer(reply::status_type status)
+{
+  switch (status)
+  {
+  case reply::ok:
+    return boost::asio::buffer(ok);
+  case reply::created:
+    return boost::asio::buffer(created);
+  case reply::accepted:
+    return boost::asio::buffer(accepted);
+  case reply::no_content:
+    return boost::asio::buffer(no_content);
+  case reply::multiple_choices:
+    return boost::asio::buffer(multiple_choices);
+  case reply::moved_permanently:
+    return boost::asio::buffer(moved_permanently);
+  case reply::moved_temporarily:
+    return boost::asio::buffer(moved_temporarily);
+  case reply::not_modified:
+    return boost::asio::buffer(not_modified);
+  case reply::bad_request:
+    return boost::asio::buffer(bad_request);
+  case reply::unauthorized:
+    return boost::asio::buffer(unauthorized);
+  case reply::forbidden:
+    return boost::asio::buffer(forbidden);
+  case reply::not_found:
+    return boost::asio::buffer(not_found);
+  case reply::internal_server_error:
+    return boost::asio::buffer(internal_server_error);
+  case reply::not_implemented:
+    return boost::asio::buffer(not_implemented);
+  case reply::bad_gateway:
+    return boost::asio::buffer(bad_gateway);
+  case reply::service_unavailable:
+    return boost::asio::buffer(service_unavailable);
+  default:
+    return boost::asio::buffer(internal_server_error);
+  }
+}
+
+} // namespace status_strings
+
+namespace misc_strings {
+
+const char name_value_separator[] = { ':', ' ' };
+const char crlf[] = { '\r', '\n' };
+
+} // namespace misc_strings
+
+std::vector<boost::asio::const_buffer> reply::to_buffers()
+{
+  std::vector<boost::asio::const_buffer> buffers;
+  buffers.push_back(status_strings::to_buffer(status));
+  for (std::size_t i = 0; i < headers.size(); ++i)
+  {
+    header& h = headers[i];
+    buffers.push_back(boost::asio::buffer(h.name));
+    buffers.push_back(boost::asio::buffer(misc_strings::name_value_separator));
+    buffers.push_back(boost::asio::buffer(h.value));
+    buffers.push_back(boost::asio::buffer(misc_strings::crlf));
+  }
+  buffers.push_back(boost::asio::buffer(misc_strings::crlf));
+  buffers.push_back(boost::asio::buffer(content));
+  return buffers;
+}
+
+namespace stock_replies {
+
+const char ok[] = "";
+const char created[] =
+  "<html>"
+  "<head><title>Created</title></head>"
+  "<body><h1>201 Created</h1></body>"
+  "</html>";
+const char accepted[] =
+  "<html>"
+  "<head><title>Accepted</title></head>"
+  "<body><h1>202 Accepted</h1></body>"
+  "</html>";
+const char no_content[] =
+  "<html>"
+  "<head><title>No Content</title></head>"
+  "<body><h1>204 Content</h1></body>"
+  "</html>";
+const char multiple_choices[] =
+  "<html>"
+  "<head><title>Multiple Choices</title></head>"
+  "<body><h1>300 Multiple Choices</h1></body>"
+  "</html>";
+const char moved_permanently[] =
+  "<html>"
+  "<head><title>Moved Permanently</title></head>"
+  "<body><h1>301 Moved Permanently</h1></body>"
+  "</html>";
+const char moved_temporarily[] =
+  "<html>"
+  "<head><title>Moved Temporarily</title></head>"
+  "<body><h1>302 Moved Temporarily</h1></body>"
+  "</html>";
+const char not_modified[] =
+  "<html>"
+  "<head><title>Not Modified</title></head>"
+  "<body><h1>304 Not Modified</h1></body>"
+  "</html>";
+const char bad_request[] =
+  "<html>"
+  "<head><title>Bad Request</title></head>"
+  "<body><h1>400 Bad Request</h1></body>"
+  "</html>";
+const char unauthorized[] =
+  "<html>"
+  "<head><title>Unauthorized</title></head>"
+  "<body><h1>401 Unauthorized</h1></body>"
+  "</html>";
+const char forbidden[] =
+  "<html>"
+  "<head><title>Forbidden</title></head>"
+  "<body><h1>403 Forbidden</h1></body>"
+  "</html>";
+const char not_found[] =
+  "<html>"
+  "<head><title>Not Found</title></head>"
+  "<body><h1>404 Not Found</h1></body>"
+  "</html>";
+const char internal_server_error[] =
+  "<html>"
+  "<head><title>Internal Server Error</title></head>"
+  "<body><h1>500 Internal Server Error</h1></body>"
+  "</html>";
+const char not_implemented[] =
+  "<html>"
+  "<head><title>Not Implemented</title></head>"
+  "<body><h1>501 Not Implemented</h1></body>"
+  "</html>";
+const char bad_gateway[] =
+  "<html>"
+  "<head><title>Bad Gateway</title></head>"
+  "<body><h1>502 Bad Gateway</h1></body>"
+  "</html>";
+const char service_unavailable[] =
+  "<html>"
+  "<head><title>Service Unavailable</title></head>"
+  "<body><h1>503 Service Unavailable</h1></body>"
+  "</html>";
+
+std::string to_string(reply::status_type status)
+{
+  switch (status)
+  {
+  case reply::ok:
+    return ok;
+  case reply::created:
+    return created;
+  case reply::accepted:
+    return accepted;
+  case reply::no_content:
+    return no_content;
+  case reply::multiple_choices:
+    return multiple_choices;
+  case reply::moved_permanently:
+    return moved_permanently;
+  case reply::moved_temporarily:
+    return moved_temporarily;
+  case reply::not_modified:
+    return not_modified;
+  case reply::bad_request:
+    return bad_request;
+  case reply::unauthorized:
+    return unauthorized;
+  case reply::forbidden:
+    return forbidden;
+  case reply::not_found:
+    return not_found;
+  case reply::internal_server_error:
+    return internal_server_error;
+  case reply::not_implemented:
+    return not_implemented;
+  case reply::bad_gateway:
+    return bad_gateway;
+  case reply::service_unavailable:
+    return service_unavailable;
+  default:
+    return internal_server_error;
+  }
+}
+
+} // namespace stock_replies
+
+reply reply::stock_reply(reply::status_type status)
+{
+  reply rep;
+  rep.status = status;
+  rep.content = stock_replies::to_string(status);
+  rep.headers.resize(2);
+  rep.headers[0].name = "Content-Length";
+  rep.headers[0].value = std::to_string(rep.content.size());
+  rep.headers[1].name = "Content-Type";
+  rep.headers[1].value = "text/html";
+  return rep;
+}
+
+} // namespace server
+} // namespace http

libs/asio/example/cpp11/http/server/reply.hpp

@@ -0,0 +1,64 @@
+//
+// reply.hpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_REPLY_HPP
+#define HTTP_REPLY_HPP
+
+#include <string>
+#include <vector>
+#include <boost/asio.hpp>
+#include "header.hpp"
+
+namespace http {
+namespace server {
+
+/// A reply to be sent to a client.
+struct reply
+{
+  /// The status of the reply.
+  enum status_type
+  {
+    ok = 200,
+    created = 201,
+    accepted = 202,
+    no_content = 204,
+    multiple_choices = 300,
+    moved_permanently = 301,
+    moved_temporarily = 302,
+    not_modified = 304,
+    bad_request = 400,
+    unauthorized = 401,
+    forbidden = 403,
+    not_found = 404,
+    internal_server_error = 500,
+    not_implemented = 501,
+    bad_gateway = 502,
+    service_unavailable = 503
+  } status;
+
+  /// The headers to be included in the reply.
+  std::vector<header> headers;
+
+  /// The content to be sent in the reply.
+  std::string content;
+
+  /// Convert the reply into a vector of buffers. The buffers do not own the
+  /// underlying memory blocks, therefore the reply object must remain valid and
+  /// not be changed until the write operation has completed.
+  std::vector<boost::asio::const_buffer> to_buffers();
+
+  /// Get a stock reply.
+  static reply stock_reply(status_type status);
+};
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_REPLY_HPP

libs/asio/example/cpp11/http/server/request.hpp

@@ -0,0 +1,34 @@
+//
+// request.hpp
+// ~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_REQUEST_HPP
+#define HTTP_REQUEST_HPP
+
+#include <string>
+#include <vector>
+#include "header.hpp"
+
+namespace http {
+namespace server {
+
+/// A request received from a client.
+struct request
+{
+  std::string method;
+  std::string uri;
+  int http_version_major;
+  int http_version_minor;
+  std::vector<header> headers;
+};
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_REQUEST_HPP

libs/asio/example/cpp11/http/server/request_handler.cpp

@@ -0,0 +1,121 @@
+//
+// request_handler.cpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "request_handler.hpp"
+#include <fstream>
+#include <sstream>
+#include <string>
+#include "mime_types.hpp"
+#include "reply.hpp"
+#include "request.hpp"
+
+namespace http {
+namespace server {
+
+request_handler::request_handler(const std::string& doc_root)
+  : doc_root_(doc_root)
+{
+}
+
+void request_handler::handle_request(const request& req, reply& rep)
+{
+  // Decode url to path.
+  std::string request_path;
+  if (!url_decode(req.uri, request_path))
+  {
+    rep = reply::stock_reply(reply::bad_request);
+    return;
+  }
+
+  // Request path must be absolute and not contain "..".
+  if (request_path.empty() || request_path[0] != '/'
+      || request_path.find("..") != std::string::npos)
+  {
+    rep = reply::stock_reply(reply::bad_request);
+    return;
+  }
+
+  // If path ends in slash (i.e. is a directory) then add "index.html".
+  if (request_path[request_path.size() - 1] == '/')
+  {
+    request_path += "index.html";
+  }
+
+  // Determine the file extension.
+  std::size_t last_slash_pos = request_path.find_last_of("/");
+  std::size_t last_dot_pos = request_path.find_last_of(".");
+  std::string extension;
+  if (last_dot_pos != std::string::npos && last_dot_pos > last_slash_pos)
+  {
+    extension = request_path.substr(last_dot_pos + 1);
+  }
+
+  // Open the file to send back.
+  std::string full_path = doc_root_ + request_path;
+  std::ifstream is(full_path.c_str(), std::ios::in | std::ios::binary);
+  if (!is)
+  {
+    rep = reply::stock_reply(reply::not_found);
+    return;
+  }
+
+  // Fill out the reply to be sent to the client.
+  rep.status = reply::ok;
+  char buf[512];
+  while (is.read(buf, sizeof(buf)).gcount() > 0)
+    rep.content.append(buf, is.gcount());
+  rep.headers.resize(2);
+  rep.headers[0].name = "Content-Length";
+  rep.headers[0].value = std::to_string(rep.content.size());
+  rep.headers[1].name = "Content-Type";
+  rep.headers[1].value = mime_types::extension_to_type(extension);
+}
+
+bool request_handler::url_decode(const std::string& in, std::string& out)
+{
+  out.clear();
+  out.reserve(in.size());
+  for (std::size_t i = 0; i < in.size(); ++i)
+  {
+    if (in[i] == '%')
+    {
+      if (i + 3 <= in.size())
+      {
+        int value = 0;
+        std::istringstream is(in.substr(i + 1, 2));
+        if (is >> std::hex >> value)
+        {
+          out += static_cast<char>(value);
+          i += 2;
+        }
+        else
+        {
+          return false;
+        }
+      }
+      else
+      {
+        return false;
+      }
+    }
+    else if (in[i] == '+')
+    {
+      out += ' ';
+    }
+    else
+    {
+      out += in[i];
+    }
+  }
+  return true;
+}
+
+} // namespace server
+} // namespace http

libs/asio/example/cpp11/http/server/request_handler.hpp

@@ -0,0 +1,47 @@
+//
+// request_handler.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_REQUEST_HANDLER_HPP
+#define HTTP_REQUEST_HANDLER_HPP
+
+#include <string>
+
+namespace http {
+namespace server {
+
+struct reply;
+struct request;
+
+/// The common handler for all incoming requests.
+class request_handler
+{
+public:
+  request_handler(const request_handler&) = delete;
+  request_handler& operator=(const request_handler&) = delete;
+
+  /// Construct with a directory containing files to be served.
+  explicit request_handler(const std::string& doc_root);
+
+  /// Handle a request and produce a reply.
+  void handle_request(const request& req, reply& rep);
+
+private:
+  /// The directory containing the files to be served.
+  std::string doc_root_;
+
+  /// Perform URL-decoding on a string. Returns false if the encoding was
+  /// invalid.
+  static bool url_decode(const std::string& in, std::string& out);
+};
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_REQUEST_HANDLER_HPP

libs/asio/example/cpp11/http/server/request_parser.cpp

@@ -0,0 +1,315 @@
+//
+// request_parser.cpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "request_parser.hpp"
+#include "request.hpp"
+
+namespace http {
+namespace server {
+
+request_parser::request_parser()
+  : state_(method_start)
+{
+}
+
+void request_parser::reset()
+{
+  state_ = method_start;
+}
+
+request_parser::result_type request_parser::consume(request& req, char input)
+{
+  switch (state_)
+  {
+  case method_start:
+    if (!is_char(input) || is_ctl(input) || is_tspecial(input))
+    {
+      return bad;
+    }
+    else
+    {
+      state_ = method;
+      req.method.push_back(input);
+      return indeterminate;
+    }
+  case method:
+    if (input == ' ')
+    {
+      state_ = uri;
+      return indeterminate;
+    }
+    else if (!is_char(input) || is_ctl(input) || is_tspecial(input))
+    {
+      return bad;
+    }
+    else
+    {
+      req.method.push_back(input);
+      return indeterminate;
+    }
+  case uri:
+    if (input == ' ')
+    {
+      state_ = http_version_h;
+      return indeterminate;
+    }
+    else if (is_ctl(input))
+    {
+      return bad;
+    }
+    else
+    {
+      req.uri.push_back(input);
+      return indeterminate;
+    }
+  case http_version_h:
+    if (input == 'H')
+    {
+      state_ = http_version_t_1;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_t_1:
+    if (input == 'T')
+    {
+      state_ = http_version_t_2;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_t_2:
+    if (input == 'T')
+    {
+      state_ = http_version_p;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_p:
+    if (input == 'P')
+    {
+      state_ = http_version_slash;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_slash:
+    if (input == '/')
+    {
+      req.http_version_major = 0;
+      req.http_version_minor = 0;
+      state_ = http_version_major_start;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_major_start:
+    if (is_digit(input))
+    {
+      req.http_version_major = req.http_version_major * 10 + input - '0';
+      state_ = http_version_major;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_major:
+    if (input == '.')
+    {
+      state_ = http_version_minor_start;
+      return indeterminate;
+    }
+    else if (is_digit(input))
+    {
+      req.http_version_major = req.http_version_major * 10 + input - '0';
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_minor_start:
+    if (is_digit(input))
+    {
+      req.http_version_minor = req.http_version_minor * 10 + input - '0';
+      state_ = http_version_minor;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case http_version_minor:
+    if (input == '\r')
+    {
+      state_ = expecting_newline_1;
+      return indeterminate;
+    }
+    else if (is_digit(input))
+    {
+      req.http_version_minor = req.http_version_minor * 10 + input - '0';
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case expecting_newline_1:
+    if (input == '\n')
+    {
+      state_ = header_line_start;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case header_line_start:
+    if (input == '\r')
+    {
+      state_ = expecting_newline_3;
+      return indeterminate;
+    }
+    else if (!req.headers.empty() && (input == ' ' || input == '\t'))
+    {
+      state_ = header_lws;
+      return indeterminate;
+    }
+    else if (!is_char(input) || is_ctl(input) || is_tspecial(input))
+    {
+      return bad;
+    }
+    else
+    {
+      req.headers.push_back(header());
+      req.headers.back().name.push_back(input);
+      state_ = header_name;
+      return indeterminate;
+    }
+  case header_lws:
+    if (input == '\r')
+    {
+      state_ = expecting_newline_2;
+      return indeterminate;
+    }
+    else if (input == ' ' || input == '\t')
+    {
+      return indeterminate;
+    }
+    else if (is_ctl(input))
+    {
+      return bad;
+    }
+    else
+    {
+      state_ = header_value;
+      req.headers.back().value.push_back(input);
+      return indeterminate;
+    }
+  case header_name:
+    if (input == ':')
+    {
+      state_ = space_before_header_value;
+      return indeterminate;
+    }
+    else if (!is_char(input) || is_ctl(input) || is_tspecial(input))
+    {
+      return bad;
+    }
+    else
+    {
+      req.headers.back().name.push_back(input);
+      return indeterminate;
+    }
+  case space_before_header_value:
+    if (input == ' ')
+    {
+      state_ = header_value;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case header_value:
+    if (input == '\r')
+    {
+      state_ = expecting_newline_2;
+      return indeterminate;
+    }
+    else if (is_ctl(input))
+    {
+      return bad;
+    }
+    else
+    {
+      req.headers.back().value.push_back(input);
+      return indeterminate;
+    }
+  case expecting_newline_2:
+    if (input == '\n')
+    {
+      state_ = header_line_start;
+      return indeterminate;
+    }
+    else
+    {
+      return bad;
+    }
+  case expecting_newline_3:
+    return (input == '\n') ? good : bad;
+  default:
+    return bad;
+  }
+}
+
+bool request_parser::is_char(int c)
+{
+  return c >= 0 && c <= 127;
+}
+
+bool request_parser::is_ctl(int c)
+{
+  return (c >= 0 && c <= 31) || (c == 127);
+}
+
+bool request_parser::is_tspecial(int c)
+{
+  switch (c)
+  {
+  case '(': case ')': case '<': case '>': case '@':
+  case ',': case ';': case ':': case '\\': case '"':
+  case '/': case '[': case ']': case '?': case '=':
+  case '{': case '}': case ' ': case '\t':
+    return true;
+  default:
+    return false;
+  }
+}
+
+bool request_parser::is_digit(int c)
+{
+  return c >= '0' && c <= '9';
+}
+
+} // namespace server
+} // namespace http

libs/asio/example/cpp11/http/server/request_parser.hpp

@@ -0,0 +1,96 @@
+//
+// request_parser.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_REQUEST_PARSER_HPP
+#define HTTP_REQUEST_PARSER_HPP
+
+#include <tuple>
+
+namespace http {
+namespace server {
+
+struct request;
+
+/// Parser for incoming requests.
+class request_parser
+{
+public:
+  /// Construct ready to parse the request method.
+  request_parser();
+
+  /// Reset to initial parser state.
+  void reset();
+
+  /// Result of parse.
+  enum result_type { good, bad, indeterminate };
+
+  /// Parse some data. The enum return value is good when a complete request has
+  /// been parsed, bad if the data is invalid, indeterminate when more data is
+  /// required. The InputIterator return value indicates how much of the input
+  /// has been consumed.
+  template <typename InputIterator>
+  std::tuple<result_type, InputIterator> parse(request& req,
+      InputIterator begin, InputIterator end)
+  {
+    while (begin != end)
+    {
+      result_type result = consume(req, *begin++);
+      if (result == good || result == bad)
+        return std::make_tuple(result, begin);
+    }
+    return std::make_tuple(indeterminate, begin);
+  }
+
+private:
+  /// Handle the next character of input.
+  result_type consume(request& req, char input);
+
+  /// Check if a byte is an HTTP character.
+  static bool is_char(int c);
+
+  /// Check if a byte is an HTTP control character.
+  static bool is_ctl(int c);
+
+  /// Check if a byte is defined as an HTTP tspecial character.
+  static bool is_tspecial(int c);
+
+  /// Check if a byte is a digit.
+  static bool is_digit(int c);
+
+  /// The current state of the parser.
+  enum state
+  {
+    method_start,
+    method,
+    uri,
+    http_version_h,
+    http_version_t_1,
+    http_version_t_2,
+    http_version_p,
+    http_version_slash,
+    http_version_major_start,
+    http_version_major,
+    http_version_minor_start,
+    http_version_minor,
+    expecting_newline_1,
+    header_line_start,
+    header_lws,
+    header_name,
+    space_before_header_value,
+    header_value,
+    expecting_newline_2,
+    expecting_newline_3
+  } state_;
+};
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_REQUEST_PARSER_HPP

libs/asio/example/cpp11/http/server/server.cpp

@@ -0,0 +1,94 @@
+//
+// server.cpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "server.hpp"
+#include <signal.h>
+#include <utility>
+
+namespace http {
+namespace server {
+
+server::server(const std::string& address, const std::string& port,
+    const std::string& doc_root)
+  : io_context_(1),
+    signals_(io_context_),
+    acceptor_(io_context_),
+    connection_manager_(),
+    request_handler_(doc_root)
+{
+  // Register to handle the signals that indicate when the server should exit.
+  // It is safe to register for the same signal multiple times in a program,
+  // provided all registration for the specified signal is made through Asio.
+  signals_.add(SIGINT);
+  signals_.add(SIGTERM);
+#if defined(SIGQUIT)
+  signals_.add(SIGQUIT);
+#endif // defined(SIGQUIT)
+
+  do_await_stop();
+
+  // Open the acceptor with the option to reuse the address (i.e. SO_REUSEADDR).
+  boost::asio::ip::tcp::resolver resolver(io_context_);
+  boost::asio::ip::tcp::endpoint endpoint =
+    *resolver.resolve(address, port).begin();
+  acceptor_.open(endpoint.protocol());
+  acceptor_.set_option(boost::asio::ip::tcp::acceptor::reuse_address(true));
+  acceptor_.bind(endpoint);
+  acceptor_.listen();
+
+  do_accept();
+}
+
+void server::run()
+{
+  // The io_context::run() call will block until all asynchronous operations
+  // have finished. While the server is running, there is always at least one
+  // asynchronous operation outstanding: the asynchronous accept call waiting
+  // for new incoming connections.
+  io_context_.run();
+}
+
+void server::do_accept()
+{
+  acceptor_.async_accept(
+      [this](boost::system::error_code ec, boost::asio::ip::tcp::socket socket)
+      {
+        // Check whether the server was stopped by a signal before this
+        // completion handler had a chance to run.
+        if (!acceptor_.is_open())
+        {
+          return;
+        }
+
+        if (!ec)
+        {
+          connection_manager_.start(std::make_shared<connection>(
+              std::move(socket), connection_manager_, request_handler_));
+        }
+
+        do_accept();
+      });
+}
+
+void server::do_await_stop()
+{
+  signals_.async_wait(
+      [this](boost::system::error_code /*ec*/, int /*signo*/)
+      {
+        // The server is stopped by cancelling all outstanding asynchronous
+        // operations. Once all operations have finished the io_context::run()
+        // call will exit.
+        acceptor_.close();
+        connection_manager_.stop_all();
+      });
+}
+
+} // namespace server
+} // namespace http

libs/asio/example/cpp11/http/server/server.hpp

@@ -0,0 +1,64 @@
+//
+// server.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef HTTP_SERVER_HPP
+#define HTTP_SERVER_HPP
+
+#include <boost/asio.hpp>
+#include <string>
+#include "connection.hpp"
+#include "connection_manager.hpp"
+#include "request_handler.hpp"
+
+namespace http {
+namespace server {
+
+/// The top-level class of the HTTP server.
+class server
+{
+public:
+  server(const server&) = delete;
+  server& operator=(const server&) = delete;
+
+  /// Construct the server to listen on the specified TCP address and port, and
+  /// serve up files from the given directory.
+  explicit server(const std::string& address, const std::string& port,
+      const std::string& doc_root);
+
+  /// Run the server's io_context loop.
+  void run();
+
+private:
+  /// Perform an asynchronous accept operation.
+  void do_accept();
+
+  /// Wait for a request to stop the server.
+  void do_await_stop();
+
+  /// The io_context used to perform asynchronous operations.
+  boost::asio::io_context io_context_;
+
+  /// The signal_set is used to register for process termination notifications.
+  boost::asio::signal_set signals_;
+
+  /// Acceptor used to listen for incoming connections.
+  boost::asio::ip::tcp::acceptor acceptor_;
+
+  /// The connection manager which owns all live connections.
+  connection_manager connection_manager_;
+
+  /// The handler for all incoming requests.
+  request_handler request_handler_;
+};
+
+} // namespace server
+} // namespace http
+
+#endif // HTTP_SERVER_HPP

libs/asio/example/cpp11/invocation/Jamfile.v2

@@ -0,0 +1,43 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe prioritised_handlers
+  : prioritised_handlers.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/invocation/prioritised_handlers.cpp

@@ -0,0 +1,202 @@
+//
+// prioritised_handlers.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/asio.hpp>
+#include <iostream>
+#include <memory>
+#include <queue>
+
+using boost::asio::ip::tcp;
+
+class handler_priority_queue : boost::asio::execution_context
+{
+public:
+  template <typename Function>
+  void add(int priority, Function function)
+  {
+    std::unique_ptr<queued_handler_base> handler(
+        new queued_handler<Function>(
+          priority, std::move(function)));
+
+    handlers_.push(std::move(handler));
+  }
+
+  void execute_all()
+  {
+    while (!handlers_.empty())
+    {
+      handlers_.top()->execute();
+      handlers_.pop();
+    }
+  }
+
+  class executor
+  {
+  public:
+    executor(handler_priority_queue& q, int p)
+      : context_(q), priority_(p)
+    {
+    }
+
+    handler_priority_queue& context() const noexcept
+    {
+      return context_;
+    }
+
+    template <typename Function, typename Allocator>
+    void dispatch(Function f, const Allocator&) const
+    {
+      context_.add(priority_, std::move(f));
+    }
+
+    template <typename Function, typename Allocator>
+    void post(Function f, const Allocator&) const
+    {
+      context_.add(priority_, std::move(f));
+    }
+
+    template <typename Function, typename Allocator>
+    void defer(Function f, const Allocator&) const
+    {
+      context_.add(priority_, std::move(f));
+    }
+
+    void on_work_started() const noexcept {}
+    void on_work_finished() const noexcept {}
+
+    bool operator==(const executor& other) const noexcept
+    {
+      return &context_ == &other.context_ && priority_ == other.priority_;
+    }
+
+    bool operator!=(const executor& other) const noexcept
+    {
+      return !operator==(other);
+    }
+
+  private:
+    handler_priority_queue& context_;
+    int priority_;
+  };
+
+  template <typename Handler>
+  boost::asio::executor_binder<Handler, executor>
+  wrap(int priority, Handler handler)
+  {
+    return boost::asio::bind_executor(
+        executor(*this, priority), std::move(handler));
+  }
+
+private:
+  class queued_handler_base
+  {
+  public:
+    queued_handler_base(int p)
+      : priority_(p)
+    {
+    }
+
+    virtual ~queued_handler_base()
+    {
+    }
+
+    virtual void execute() = 0;
+
+    friend bool operator<(const std::unique_ptr<queued_handler_base>& a,
+        const std::unique_ptr<queued_handler_base>& b) noexcept
+    {
+      return a->priority_ < b->priority_;
+    }
+
+  private:
+    int priority_;
+  };
+
+  template <typename Function>
+  class queued_handler : public queued_handler_base
+  {
+  public:
+    queued_handler(int p, Function f)
+      : queued_handler_base(p), function_(std::move(f))
+    {
+    }
+
+    void execute() override
+    {
+      function_();
+    }
+
+  private:
+    Function function_;
+  };
+
+  std::priority_queue<std::unique_ptr<queued_handler_base>> handlers_;
+};
+
+//----------------------------------------------------------------------
+
+void high_priority_handler(const boost::system::error_code& /*ec*/)
+{
+  std::cout << "High priority handler\n";
+}
+
+void middle_priority_handler(const boost::system::error_code& /*ec*/)
+{
+  std::cout << "Middle priority handler\n";
+}
+
+struct low_priority_handler
+{
+  // Make the handler a move-only type.
+  low_priority_handler() = default;
+  low_priority_handler(const low_priority_handler&) = delete;
+  low_priority_handler(low_priority_handler&&) = default;
+
+  void operator()()
+  {
+    std::cout << "Low priority handler\n";
+  }
+};
+
+int main()
+{
+  boost::asio::io_context io_context;
+
+  handler_priority_queue pri_queue;
+
+  // Post a completion handler to be run immediately.
+  boost::asio::post(io_context, pri_queue.wrap(0, low_priority_handler()));
+
+  // Start an asynchronous accept that will complete immediately.
+  tcp::endpoint endpoint(boost::asio::ip::address_v4::loopback(), 0);
+  tcp::acceptor acceptor(io_context, endpoint);
+  tcp::socket server_socket(io_context);
+  acceptor.async_accept(server_socket,
+      pri_queue.wrap(100, high_priority_handler));
+  tcp::socket client_socket(io_context);
+  client_socket.connect(acceptor.local_endpoint());
+
+  // Set a deadline timer to expire immediately.
+  boost::asio::steady_timer timer(io_context);
+  timer.expires_at(boost::asio::steady_timer::clock_type::time_point::min());
+  timer.async_wait(pri_queue.wrap(42, middle_priority_handler));
+
+  while (io_context.run_one())
+  {
+    // The custom invocation hook adds the handlers to the priority queue
+    // rather than executing them from within the poll_one() call.
+    while (io_context.poll_one())
+      ;
+
+    pri_queue.execute_all();
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/local/Jamfile.v2

@@ -0,0 +1,92 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe connect_pair
+  : connect_pair.cpp
+    /boost/system//boost_system
+    /boost/thread//boost_thread
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe iostream_client
+  : iostream_client.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe stream_client
+  : stream_client.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe stream_server
+  : stream_server.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/local/connect_pair.cpp

@@ -0,0 +1,130 @@
+//
+// connect_pair.cpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <array>
+#include <iostream>
+#include <string>
+#include <cctype>
+#include <boost/asio.hpp>
+#include <boost/thread/thread.hpp>
+
+#if defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+
+using boost::asio::local::stream_protocol;
+
+class uppercase_filter
+{
+public:
+  uppercase_filter(stream_protocol::socket sock)
+    : socket_(std::move(sock))
+  {
+    read();
+  }
+
+private:
+  void read()
+  {
+    socket_.async_read_some(boost::asio::buffer(data_),
+        [this](boost::system::error_code ec, std::size_t size)
+        {
+          if (!ec)
+          {
+            // Compute result.
+            for (std::size_t i = 0; i < size; ++i)
+              data_[i] = std::toupper(data_[i]);
+
+            // Send result.
+            write(size);
+          }
+          else
+          {
+            throw boost::system::system_error(ec);
+          }
+        });
+  }
+
+  void write(std::size_t size)
+  {
+    boost::asio::async_write(socket_, boost::asio::buffer(data_, size),
+        [this](boost::system::error_code ec, std::size_t /*size*/)
+        {
+          if (!ec)
+          {
+            // Wait for request.
+            read();
+          }
+          else
+          {
+            throw boost::system::system_error(ec);
+          }
+        });
+  }
+
+  stream_protocol::socket socket_;
+  std::array<char, 512> data_;
+};
+
+int main()
+{
+  try
+  {
+    boost::asio::io_context io_context;
+
+    // Create a connected pair and pass one end to a filter.
+    stream_protocol::socket socket(io_context);
+    stream_protocol::socket filter_socket(io_context);
+    boost::asio::local::connect_pair(socket, filter_socket);
+    uppercase_filter filter(std::move(filter_socket));
+
+    // The io_context runs in a background thread to perform filtering.
+    boost::thread thread(
+        [&io_context]()
+        {
+          try
+          {
+            io_context.run();
+          }
+          catch (std::exception& e)
+          {
+            std::cerr << "Exception in thread: " << e.what() << "\n";
+            std::exit(1);
+          }
+        });
+
+    for (;;)
+    {
+      // Collect request from user.
+      std::cout << "Enter a string: ";
+      std::string request;
+      std::getline(std::cin, request);
+
+      // Send request to filter.
+      boost::asio::write(socket, boost::asio::buffer(request));
+
+      // Wait for reply from filter.
+      std::vector<char> reply(request.size());
+      boost::asio::read(socket, boost::asio::buffer(reply));
+
+      // Show reply to user.
+      std::cout << "Result: ";
+      std::cout.write(&reply[0], request.size());
+      std::cout << std::endl;
+    }
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+    std::exit(1);
+  }
+}
+
+#else // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)

libs/asio/example/cpp11/local/iostream_client.cpp

@@ -0,0 +1,61 @@
+//
+// stream_client.cpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstring>
+#include <iostream>
+#include <boost/asio.hpp>
+
+#if defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+
+using boost::asio::local::stream_protocol;
+
+constexpr std::size_t max_length = 1024;
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: iostream_client <file>\n";
+      return 1;
+    }
+
+    stream_protocol::endpoint ep(argv[1]);
+    stream_protocol::iostream s(ep);
+    if (!s)
+    {
+      std::cerr << "Unable to connect: " << s.error().message() << std::endl;
+      return 1;
+    }
+
+    std::cout << "Enter message: ";
+    char request[max_length];
+    std::cin.getline(request, max_length);
+    size_t length = std::strlen(request);
+    s << request;
+
+    char reply[max_length];
+    s.read(reply, length);
+    std::cout << "Reply is: ";
+    std::cout.write(reply, length);
+    std::cout << "\n";
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}
+
+#else // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)

libs/asio/example/cpp11/local/stream_client.cpp

@@ -0,0 +1,60 @@
+//
+// stream_client.cpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <boost/asio.hpp>
+
+#if defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+
+using boost::asio::local::stream_protocol;
+
+constexpr std::size_t max_length = 1024;
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: stream_client <file>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    stream_protocol::socket s(io_context);
+    s.connect(stream_protocol::endpoint(argv[1]));
+
+    std::cout << "Enter message: ";
+    char request[max_length];
+    std::cin.getline(request, max_length);
+    size_t request_length = std::strlen(request);
+    boost::asio::write(s, boost::asio::buffer(request, request_length));
+
+    char reply[max_length];
+    size_t reply_length = boost::asio::read(s,
+        boost::asio::buffer(reply, request_length));
+    std::cout << "Reply is: ";
+    std::cout.write(reply, reply_length);
+    std::cout << "\n";
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}
+
+#else // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)

libs/asio/example/cpp11/local/stream_server.cpp

@@ -0,0 +1,121 @@
+//
+// stream_server.cpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <array>
+#include <cstdio>
+#include <iostream>
+#include <memory>
+#include <boost/asio.hpp>
+
+#if defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+
+using boost::asio::local::stream_protocol;
+
+class session
+  : public std::enable_shared_from_this<session>
+{
+public:
+  session(stream_protocol::socket sock)
+    : socket_(std::move(sock))
+  {
+  }
+
+  void start()
+  {
+    do_read();
+  }
+
+private:
+  void do_read()
+  {
+    auto self(shared_from_this());
+    socket_.async_read_some(boost::asio::buffer(data_),
+        [this, self](boost::system::error_code ec, std::size_t length)
+        {
+          if (!ec)
+            do_write(length);
+        });
+  }
+
+  void do_write(std::size_t length)
+  {
+    auto self(shared_from_this());
+    boost::asio::async_write(socket_,
+        boost::asio::buffer(data_, length),
+        [this, self](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+            do_read();
+        });
+  }
+
+  // The socket used to communicate with the client.
+  stream_protocol::socket socket_;
+
+  // Buffer used to store data received from the client.
+  std::array<char, 1024> data_;
+};
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, const std::string& file)
+    : acceptor_(io_context, stream_protocol::endpoint(file))
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, stream_protocol::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<session>(std::move(socket))->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  stream_protocol::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: stream_server <file>\n";
+      std::cerr << "*** WARNING: existing file is removed ***\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    std::remove(argv[1]);
+    server s(io_context, argv[1]);
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}
+
+#else // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)

libs/asio/example/cpp11/multicast/Jamfile.v2

@@ -0,0 +1,46 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+project
+  : requirements
+    <library>/boost/system//boost_system
+    <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;
+
+exe receiver : receiver.cpp ;
+exe sender : sender.cpp ;

libs/asio/example/cpp11/multicast/receiver.cpp

@@ -0,0 +1,88 @@
+//
+// receiver.cpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <array>
+#include <iostream>
+#include <string>
+#include <boost/asio.hpp>
+
+constexpr short multicast_port = 30001;
+
+class receiver
+{
+public:
+  receiver(boost::asio::io_context& io_context,
+      const boost::asio::ip::address& listen_address,
+      const boost::asio::ip::address& multicast_address)
+    : socket_(io_context)
+  {
+    // Create the socket so that multiple may be bound to the same address.
+    boost::asio::ip::udp::endpoint listen_endpoint(
+        listen_address, multicast_port);
+    socket_.open(listen_endpoint.protocol());
+    socket_.set_option(boost::asio::ip::udp::socket::reuse_address(true));
+    socket_.bind(listen_endpoint);
+
+    // Join the multicast group.
+    socket_.set_option(
+        boost::asio::ip::multicast::join_group(multicast_address));
+
+    do_receive();
+  }
+
+private:
+  void do_receive()
+  {
+    socket_.async_receive_from(
+        boost::asio::buffer(data_), sender_endpoint_,
+        [this](boost::system::error_code ec, std::size_t length)
+        {
+          if (!ec)
+          {
+            std::cout.write(data_.data(), length);
+            std::cout << std::endl;
+
+            do_receive();
+          }
+        });
+  }
+
+  boost::asio::ip::udp::socket socket_;
+  boost::asio::ip::udp::endpoint sender_endpoint_;
+  std::array<char, 1024> data_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 3)
+    {
+      std::cerr << "Usage: receiver <listen_address> <multicast_address>\n";
+      std::cerr << "  For IPv4, try:\n";
+      std::cerr << "    receiver 0.0.0.0 239.255.0.1\n";
+      std::cerr << "  For IPv6, try:\n";
+      std::cerr << "    receiver 0::0 ff31::8000:1234\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+    receiver r(io_context,
+        boost::asio::ip::make_address(argv[1]),
+        boost::asio::ip::make_address(argv[2]));
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/multicast/sender.cpp

@@ -0,0 +1,91 @@
+//
+// sender.cpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <boost/asio.hpp>
+
+constexpr short multicast_port = 30001;
+constexpr int max_message_count = 10;
+
+class sender
+{
+public:
+  sender(boost::asio::io_context& io_context,
+      const boost::asio::ip::address& multicast_address)
+    : endpoint_(multicast_address, multicast_port),
+      socket_(io_context, endpoint_.protocol()),
+      timer_(io_context),
+      message_count_(0)
+  {
+    do_send();
+  }
+
+private:
+  void do_send()
+  {
+    std::ostringstream os;
+    os << "Message " << message_count_++;
+    message_ = os.str();
+
+    socket_.async_send_to(
+        boost::asio::buffer(message_), endpoint_,
+        [this](boost::system::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec && message_count_ < max_message_count)
+            do_timeout();
+        });
+  }
+
+  void do_timeout()
+  {
+    timer_.expires_after(std::chrono::seconds(1));
+    timer_.async_wait(
+        [this](boost::system::error_code ec)
+        {
+          if (!ec)
+            do_send();
+        });
+  }
+
+private:
+  boost::asio::ip::udp::endpoint endpoint_;
+  boost::asio::ip::udp::socket socket_;
+  boost::asio::steady_timer timer_;
+  int message_count_;
+  std::string message_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: sender <multicast_address>\n";
+      std::cerr << "  For IPv4, try:\n";
+      std::cerr << "    sender 239.255.0.1\n";
+      std::cerr << "  For IPv6, try:\n";
+      std::cerr << "    sender ff31::8000:1234\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+    sender s(io_context, boost::asio::ip::make_address(argv[1]));
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/nonblocking/Jamfile.v2

@@ -0,0 +1,43 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe third_party_lib
+  : third_party_lib.cpp
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/nonblocking/third_party_lib.cpp

@@ -0,0 +1,212 @@
+//
+// third_party_lib.cpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/asio.hpp>
+#include <array>
+#include <iostream>
+#include <memory>
+
+using boost::asio::ip::tcp;
+
+namespace third_party_lib {
+
+// Simulation of a third party library that wants to perform read and write
+// operations directly on a socket. It needs to be polled to determine whether
+// it requires a read or write operation, and notified when the socket is ready
+// for reading or writing.
+class session
+{
+public:
+  session(tcp::socket& socket)
+    : socket_(socket)
+  {
+  }
+
+  // Returns true if the third party library wants to be notified when the
+  // socket is ready for reading.
+  bool want_read() const
+  {
+    return state_ == reading;
+  }
+
+  // Notify that third party library that it should perform its read operation.
+  void do_read(boost::system::error_code& ec)
+  {
+    if (std::size_t len = socket_.read_some(boost::asio::buffer(data_), ec))
+    {
+      write_buffer_ = boost::asio::buffer(data_, len);
+      state_ = writing;
+    }
+  }
+
+  // Returns true if the third party library wants to be notified when the
+  // socket is ready for writing.
+  bool want_write() const
+  {
+    return state_ == writing;
+  }
+
+  // Notify that third party library that it should perform its write operation.
+  void do_write(boost::system::error_code& ec)
+  {
+    if (std::size_t len = socket_.write_some(
+          boost::asio::buffer(write_buffer_), ec))
+    {
+      write_buffer_ = write_buffer_ + len;
+      state_ = boost::asio::buffer_size(write_buffer_) > 0 ? writing : reading;
+    }
+  }
+
+private:
+  tcp::socket& socket_;
+  enum { reading, writing } state_ = reading;
+  std::array<char, 128> data_;
+  boost::asio::const_buffer write_buffer_;
+};
+
+} // namespace third_party_lib
+
+// The glue between asio's sockets and the third party library.
+class connection
+  : public std::enable_shared_from_this<connection>
+{
+public:
+  connection(tcp::socket socket)
+    : socket_(std::move(socket))
+  {
+  }
+
+  void start()
+  {
+    // Put the socket into non-blocking mode.
+    socket_.non_blocking(true);
+
+    do_operations();
+  }
+
+private:
+  void do_operations()
+  {
+    auto self(shared_from_this());
+
+    // Start a read operation if the third party library wants one.
+    if (session_impl_.want_read() && !read_in_progress_)
+    {
+      read_in_progress_ = true;
+      socket_.async_wait(tcp::socket::wait_read,
+          [this, self](boost::system::error_code ec)
+          {
+            read_in_progress_ = false;
+
+            // Notify third party library that it can perform a read.
+            if (!ec)
+              session_impl_.do_read(ec);
+
+            // The third party library successfully performed a read on the
+            // socket. Start new read or write operations based on what it now
+            // wants.
+            if (!ec || ec == boost::asio::error::would_block)
+              do_operations();
+
+            // Otherwise, an error occurred. Closing the socket cancels any
+            // outstanding asynchronous read or write operations. The
+            // connection object will be destroyed automatically once those
+            // outstanding operations complete.
+            else
+              socket_.close();
+          });
+    }
+
+    // Start a write operation if the third party library wants one.
+    if (session_impl_.want_write() && !write_in_progress_)
+    {
+      write_in_progress_ = true;
+      socket_.async_wait(tcp::socket::wait_write,
+          [this, self](boost::system::error_code ec)
+          {
+            write_in_progress_ = false;
+
+            // Notify third party library that it can perform a write.
+            if (!ec)
+              session_impl_.do_write(ec);
+
+            // The third party library successfully performed a write on the
+            // socket. Start new read or write operations based on what it now
+            // wants.
+            if (!ec || ec == boost::asio::error::would_block)
+              do_operations();
+
+            // Otherwise, an error occurred. Closing the socket cancels any
+            // outstanding asynchronous read or write operations. The
+            // connection object will be destroyed automatically once those
+            // outstanding operations complete.
+            else
+              socket_.close();
+          });
+    }
+  }
+
+private:
+  tcp::socket socket_;
+  third_party_lib::session session_impl_{socket_};
+  bool read_in_progress_ = false;
+  bool write_in_progress_ = false;
+};
+
+class server
+{
+public:
+  server(boost::asio::io_context& io_context, unsigned short port)
+    : acceptor_(io_context, {tcp::v4(), port})
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](boost::system::error_code ec, tcp::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<connection>(std::move(socket))->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  tcp::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: third_party_lib <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    server s(io_context, std::atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/spawn/Jamfile.v2

@@ -0,0 +1,45 @@
+#
+# Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+  lib socket ;
+  lib nsl ;
+}
+else if [ os.name ] = NT
+{
+  lib ws2_32 ;
+  lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+  lib ipv6 ;
+}
+else if [ os.name ] = HAIKU
+{
+  lib network ;
+}
+
+exe server
+  : echo_server.cpp
+    /boost/context//boost_context
+    /boost/coroutine//boost_coroutine
+    /boost/system//boost_system
+  : <define>BOOST_ALL_NO_LIB=1
+    <threading>multi
+    <os>SOLARIS:<library>socket
+    <os>SOLARIS:<library>nsl
+    <os>NT:<define>_WIN32_WINNT=0x0501
+    <os>NT,<toolset>gcc:<library>ws2_32
+    <os>NT,<toolset>gcc:<library>mswsock
+    <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+    <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+    <os>HPUX:<library>ipv6
+    <os>HAIKU:<library>network
+  ;

libs/asio/example/cpp11/spawn/echo_server.cpp

@@ -0,0 +1,108 @@
+//
+// echo_server.cpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/spawn.hpp>
+#include <boost/asio/steady_timer.hpp>
+#include <boost/asio/write.hpp>
+#include <iostream>
+#include <memory>
+
+using boost::asio::ip::tcp;
+
+class session : public std::enable_shared_from_this<session>
+{
+public:
+  explicit session(tcp::socket socket)
+    : socket_(std::move(socket)),
+      timer_(socket_.get_io_context()),
+      strand_(socket_.get_io_context())
+  {
+  }
+
+  void go()
+  {
+    auto self(shared_from_this());
+    boost::asio::spawn(strand_,
+        [this, self](boost::asio::yield_context yield)
+        {
+          try
+          {
+            char data[128];
+            for (;;)
+            {
+              timer_.expires_from_now(std::chrono::seconds(10));
+              std::size_t n = socket_.async_read_some(boost::asio::buffer(data), yield);
+              boost::asio::async_write(socket_, boost::asio::buffer(data, n), yield);
+            }
+          }
+          catch (std::exception& e)
+          {
+            socket_.close();
+            timer_.cancel();
+          }
+        });
+
+    boost::asio::spawn(strand_,
+        [this, self](boost::asio::yield_context yield)
+        {
+          while (socket_.is_open())
+          {
+            boost::system::error_code ignored_ec;
+            timer_.async_wait(yield[ignored_ec]);
+            if (timer_.expires_from_now() <= std::chrono::seconds(0))
+              socket_.close();
+          }
+        });
+  }
+
+private:
+  tcp::socket socket_;
+  boost::asio::steady_timer timer_;
+  boost::asio::io_context::strand strand_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: echo_server <port>\n";
+      return 1;
+    }
+
+    boost::asio::io_context io_context;
+
+    boost::asio::spawn(io_context,
+        [&](boost::asio::yield_context yield)
+        {
+          tcp::acceptor acceptor(io_context,
+            tcp::endpoint(tcp::v4(), std::atoi(argv[1])));
+
+          for (;;)
+          {
+            boost::system::error_code ec;
+            tcp::socket socket(io_context);
+            acceptor.async_accept(socket, yield[ec]);
+            if (!ec) std::make_shared<session>(std::move(socket))->go();
+          }
+        });
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

libs/asio/example/cpp11/spawn/parallel_grep.cpp

@@ -0,0 +1,84 @@
+//
+// parallel_grep.cpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/asio/dispatch.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/asio/spawn.hpp>
+#include <boost/asio/strand.hpp>
+#include <boost/asio/thread_pool.hpp>
+#include <fstream>
+#include <iostream>
+#include <string>
+
+using boost::asio::dispatch;
+using boost::asio::spawn;
+using boost::asio::strand;
+using boost::asio::thread_pool;
+using boost::asio::yield_context;
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc < 2)
+    {
+      std::cerr << "Usage: parallel_grep <string> <files...>\n";
+      return 1;
+    }
+
+    // We use a fixed size pool of threads for reading the input files. The
+    // number of threads is automatically determined based on the number of
+    // CPUs available in the system.
+    thread_pool pool;
+
+    // To prevent the output from being garbled, we use a strand to synchronise
+    // printing.
+    strand<thread_pool::executor_type> output_strand(pool.get_executor());
+
+    // Spawn a new coroutine for each file specified on the command line.
+    std::string search_string = argv[1];
+    for (int argn = 2; argn < argc; ++argn)
+    {
+      std::string input_file = argv[argn];
+      spawn(pool,
+        [=](yield_context yield)
+        {
+          std::ifstream is(input_file.c_str());
+          std::string line;
+          std::size_t line_num = 0;
+          while (std::getline(is, line))
+          {
+            // If we find a match, send a message to the output.
+            if (line.find(search_string) != std::string::npos)
+            {
+              dispatch(output_strand,
+                  [=]
+                  {
+                    std::cout << input_file << ':' << line << std::endl;
+                  });
+            }
+
+            // Every so often we yield control to another coroutine.
+            if (++line_num % 10 == 0)
+              post(yield);
+          }
+        });
+    }
+
+    // Join the thread pool to wait for all the spawned tasks to complete.
+    pool.join();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}