Create C++11 versions of the fork, local, multicast and nonblocking examples.

asio/boostify.pl

@@ -518,10 +518,15 @@ sub copy_examples
       "src/examples/cpp11/chat",
       "src/examples/cpp11/echo",
       "src/examples/cpp11/executors",
+      "src/examples/cpp11/fork",
       "src/examples/cpp11/futures",
+      "src/examples/cpp11/handler_tracking",
       "src/examples/cpp11/http/server",
       "src/examples/cpp11/invocation",
       "src/examples/cpp11/iostreams",
+      "src/examples/cpp11/local",
+      "src/examples/cpp11/multicast",
+      "src/examples/cpp11/nonblocking",
       "src/examples/cpp11/spawn",
       "src/examples/cpp14/executors");
 

asio/src/doc/examples.qbk

@@ -313,6 +313,7 @@ coroutines.
 Examples showing how to use UNIX domain (local) sockets.
 
 * [@../src/examples/cpp03/local/connect_pair.cpp]
+* [@../src/examples/cpp03/local/iostream_client.cpp]
 * [@../src/examples/cpp03/local/stream_server.cpp]
 * [@../src/examples/cpp03/local/stream_client.cpp]
 
@@ -370,6 +371,20 @@ and asynchronous operations.
 * [@../src/examples/cpp11/echo/blocking_udp_echo_server.cpp] ([@examples/diffs/echo/blocking_udp_echo_server.cpp.html diff to C++03])
 
 
+[heading Fork]
+
+These POSIX-specific examples show how to use Asio in conjunction with the
+`fork()` system call. The first example illustrates the steps required to start
+a daemon process:
+
+* [@../src/examples/cpp11/fork/daemon.cpp] ([@examples/diffs/fork/daemon.cpp.html diff to C++03])
+
+The second example demonstrates how it is possible to fork a process from
+within a completion handler.
+
+* [@../src/examples/cpp11/fork/process_per_connection.cpp] ([@examples/diffs/fork/process_per_connection.cpp.html diff to C++03])
+
+
 [heading Futures]
 
 This example demonstrates how to use std::future in conjunction with
@@ -378,6 +393,13 @@ Asio's asynchronous operations.
 * [@../src/examples/cpp11/futures/daytime_client.cpp]
 
 
+[heading Handler Tracking]
+
+This example shows how to implement custom handler tracking.
+
+* [@../src/examples/cpp11/handler_tracking/custom_tracking.hpp]
+
+
 [heading HTTP Server]
 
 This example illustrates the use of asio in a simple single-threaded server
@@ -403,6 +425,23 @@ cancelling all outstanding asynchronous operations.
 * [@../src/examples/cpp11/http/server/server.hpp] ([@examples/diffs/http/server/server.hpp.html diff to C++03])
 
 
+[heading Multicast]
+
+An example showing the use of multicast to transmit packets to a group of
+subscribers.
+
+* [@../src/examples/cpp11/multicast/receiver.cpp] ([@examples/diffs/multicast/receiver.cpp.html diff to C++03])
+* [@../src/examples/cpp11/multicast/sender.cpp] ([@examples/diffs/multicast/sender.cpp.html diff to C++03])
+
+
+[heading Nonblocking]
+
+Example demonstrating reactor-style operations for integrating a third-party
+library that wants to perform the I/O operations itself.
+
+* [@../src/examples/cpp11/nonblocking/third_party_lib.cpp] ([@examples/diffs/nonblocking/third_party_lib.cpp.html diff to C++03])
+
+
 [heading Spawn]
 
 Example of using the asio::spawn() function, a wrapper around the
@@ -413,6 +452,16 @@ coroutines.
 * [@../src/examples/cpp11/spawn/echo_server.cpp] ([@examples/diffs/spawn/echo_server.cpp.html diff to C++03])
 
 
+[heading UNIX Domain Sockets]
+
+Examples showing how to use UNIX domain (local) sockets.
+
+* [@../src/examples/cpp11/local/connect_pair.cpp] ([@examples/diffs/local/connect_pair.cpp.html diff to C++03])
+* [@../src/examples/cpp11/local/iostream_client.cpp] ([@examples/diffs/local/iostream_client.cpp.html diff to C++03])
+* [@../src/examples/cpp11/local/stream_server.cpp] ([@examples/diffs/local/stream_server.cpp.html diff to C++03])
+* [@../src/examples/cpp11/local/stream_client.cpp] ([@examples/diffs/local/stream_client.cpp.html diff to C++03])
+
+
 [endsect]
 
 

asio/src/examples/cpp11/Makefile.am

@@ -29,7 +29,20 @@ noinst_PROGRAMS = \
 	futures/daytime_client \
 	http/server/http_server \
 	invocation/prioritised_handlers \
-	iostreams/http_client
+	iostreams/http_client \
+	multicast/receiver \
+	multicast/sender \
+	nonblocking/third_party_lib
+
+if !WINDOWS_TARGET
+noinst_PROGRAMS += \
+	fork/daemon \
+	fork/process_per_connection \
+	local/connect_pair \
+	local/iostream_client \
+	local/stream_server \
+	local/stream_client
+endif
 
 if HAVE_BOOST_COROUTINE
 noinst_PROGRAMS += \
@@ -70,6 +83,18 @@ http_server_http_server_SOURCES = \
 	http/server/server.cpp
 invocation_prioritised_handlers_SOURCES = invocation/prioritised_handlers.cpp
 iostreams_http_client_SOURCES = iostreams/http_client.cpp
+multicast_receiver_SOURCES = multicast/receiver.cpp
+multicast_sender_SOURCES = multicast/sender.cpp
+nonblocking_third_party_lib_SOURCES = nonblocking/third_party_lib.cpp
+
+if !WINDOWS_TARGET
+fork_daemon_SOURCES = fork/daemon.cpp
+fork_process_per_connection_SOURCES = fork/process_per_connection.cpp
+local_connect_pair_SOURCES = local/connect_pair.cpp
+local_iostream_client_SOURCES = local/iostream_client.cpp
+local_stream_server_SOURCES = local/stream_server.cpp
+local_stream_client_SOURCES = local/stream_client.cpp
+endif
 
 if HAVE_BOOST_COROUTINE
 spawn_echo_server_SOURCES = spawn/echo_server.cpp

asio/src/examples/cpp11/fork/.gitignore

@@ -0,0 +1,11 @@
+.deps
+.dirstamp
+*.o
+*.obj
+*.exe
+*.ilk
+*.manifest
+*.pdb
+*.tds
+daemon
+process_per_connection

asio/src/examples/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 <asio/io_context.hpp>
+#include <asio/ip/udp.hpp>
+#include <asio/signal_set.hpp>
+#include <array>
+#include <ctime>
+#include <iostream>
+#include <syslog.h>
+#include <unistd.h>
+
+using asio::ip::udp;
+
+class udp_daytime_server
+{
+public:
+  udp_daytime_server(asio::io_context& io_context)
+    : socket_(io_context, {udp::v4(), 13})
+  {
+    receive();
+  }
+
+private:
+  void receive()
+  {
+    socket_.async_receive_from(
+        asio::buffer(recv_buffer_), remote_endpoint_,
+        [this](std::error_code ec, std::size_t /*n*/)
+        {
+          if (!ec || ec == asio::error::message_size)
+          {
+            using namespace std; // For time_t, time and ctime;
+            time_t now = time(0);
+            std::string message = ctime(&now);
+
+            std::error_code ignored_ec;
+            socket_.send_to(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
+  {
+    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.
+    asio::signal_set signals(io_context, SIGINT, SIGTERM);
+    signals.async_wait(
+        [&](std::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(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(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(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(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;
+  }
+}

asio/src/examples/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 <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/signal_set.hpp>
+#include <asio/write.hpp>
+#include <cstdlib>
+#include <iostream>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+using asio::ip::tcp;
+
+class server
+{
+public:
+  server(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](std::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](std::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(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(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(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(asio::buffer(data_),
+        [this](std::error_code ec, std::size_t length)
+        {
+          if (!ec)
+            write(length);
+        });
+  }
+
+  void write(std::size_t length)
+  {
+    asio::async_write(socket_, asio::buffer(data_, length),
+        [this](std::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+            read();
+        });
+  }
+
+  asio::io_context& io_context_;
+  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;
+    }
+
+    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;
+  }
+}

asio/src/examples/cpp11/handler_tracking/custom_tracking.hpp

@@ -72,8 +72,8 @@ struct custom_tracking
   }
 
   // Record the creation of a tracked handler.
-  static void creation(asio::execution_context& /*ctx*/, tracked_handler& h,
+  static void creation(asio::execution_context& /*ctx*/,
-      const char* object_type, void* /*object*/,
+      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.

asio/src/examples/cpp11/local/.gitignore

@@ -0,0 +1,13 @@
+.deps
+.dirstamp
+*.o
+*.obj
+*.exe
+connect_pair
+stream_server
+stream_client
+iostream_client
+*.ilk
+*.manifest
+*.pdb
+*.tds

asio/src/examples/cpp11/local/connect_pair.cpp

@@ -0,0 +1,129 @@
+//
+// 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 <asio.hpp>
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS)
+
+using 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(asio::buffer(data_),
+        [this](std::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 asio::system_error(ec);
+          }
+        });
+  }
+
+  void write(std::size_t size)
+  {
+    asio::async_write(socket_, asio::buffer(data_, size),
+        [this](std::error_code ec, std::size_t /*size*/)
+        {
+          if (!ec)
+          {
+            // Wait for request.
+            read();
+          }
+          else
+          {
+            throw asio::system_error(ec);
+          }
+        });
+  }
+
+  stream_protocol::socket socket_;
+  std::array<char, 512> data_;
+};
+
+int main()
+{
+  try
+  {
+    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);
+    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.
+    asio::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.
+      asio::write(socket, asio::buffer(request));
+
+      // Wait for reply from filter.
+      std::vector<char> reply(request.size());
+      asio::read(socket, 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(ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)

asio/src/examples/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 "asio.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS)
+
+using 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(ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)

asio/src/examples/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 "asio.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS)
+
+using 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;
+    }
+
+    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);
+    asio::write(s, asio::buffer(request, request_length));
+
+    char reply[max_length];
+    size_t reply_length = asio::read(s,
+        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(ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)

asio/src/examples/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 "asio.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS)
+
+using 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(asio::buffer(data_),
+        [this, self](std::error_code ec, std::size_t length)
+        {
+          if (!ec)
+            do_write(length);
+        });
+  }
+
+  void do_write(std::size_t length)
+  {
+    auto self(shared_from_this());
+    asio::async_write(socket_,
+        asio::buffer(data_, length),
+        [this, self](std::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(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](std::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;
+    }
+
+    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(ASIO_HAS_LOCAL_SOCKETS)
+# error Local sockets not available on this platform.
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)

asio/src/examples/cpp11/multicast/.gitignore

@@ -0,0 +1,11 @@
+.deps
+.dirstamp
+receiver
+sender
+*.o
+*.obj
+*.exe
+*.ilk
+*.manifest
+*.pdb
+*.tds

asio/src/examples/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 "asio.hpp"
+
+constexpr short multicast_port = 30001;
+
+class receiver
+{
+public:
+  receiver(asio::io_context& io_context,
+      const asio::ip::address& listen_address,
+      const asio::ip::address& multicast_address)
+    : socket_(io_context)
+  {
+    // Create the socket so that multiple may be bound to the same address.
+    asio::ip::udp::endpoint listen_endpoint(
+        listen_address, multicast_port);
+    socket_.open(listen_endpoint.protocol());
+    socket_.set_option(asio::ip::udp::socket::reuse_address(true));
+    socket_.bind(listen_endpoint);
+
+    // Join the multicast group.
+    socket_.set_option(
+        asio::ip::multicast::join_group(multicast_address));
+
+    do_receive();
+  }
+
+private:
+  void do_receive()
+  {
+    socket_.async_receive_from(
+        asio::buffer(data_), sender_endpoint_,
+        [this](std::error_code ec, std::size_t length)
+        {
+          if (!ec)
+          {
+            std::cout.write(data_.data(), length);
+            std::cout << std::endl;
+
+            do_receive();
+          }
+        });
+  }
+
+  asio::ip::udp::socket socket_;
+  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;
+    }
+
+    asio::io_context io_context;
+    receiver r(io_context,
+        asio::ip::make_address(argv[1]),
+        asio::ip::make_address(argv[2]));
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

asio/src/examples/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 "asio.hpp"
+
+constexpr short multicast_port = 30001;
+constexpr int max_message_count = 10;
+
+class sender
+{
+public:
+  sender(asio::io_context& io_context,
+      const 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(
+        asio::buffer(message_), endpoint_,
+        [this](std::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](std::error_code ec)
+        {
+          if (!ec)
+            do_send();
+        });
+  }
+
+private:
+  asio::ip::udp::endpoint endpoint_;
+  asio::ip::udp::socket socket_;
+  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;
+    }
+
+    asio::io_context io_context;
+    sender s(io_context, asio::ip::make_address(argv[1]));
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}

asio/src/examples/cpp11/nonblocking/.gitignore

@@ -0,0 +1,10 @@
+.deps
+.dirstamp
+*.o
+*.obj
+*.exe
+third_party_lib
+*.ilk
+*.manifest
+*.pdb
+*.tds

asio/src/examples/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 <asio.hpp>
+#include <array>
+#include <iostream>
+#include <memory>
+
+using 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(std::error_code& ec)
+  {
+    if (std::size_t len = socket_.read_some(asio::buffer(data_), ec))
+    {
+      write_buffer_ = 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(std::error_code& ec)
+  {
+    if (std::size_t len = socket_.write_some(
+          asio::buffer(write_buffer_), ec))
+    {
+      write_buffer_ = write_buffer_ + len;
+      state_ = asio::buffer_size(write_buffer_) > 0 ? writing : reading;
+    }
+  }
+
+private:
+  tcp::socket& socket_;
+  enum { reading, writing } state_ = reading;
+  std::array<char, 128> data_;
+  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](std::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 == 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](std::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 == 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(asio::io_context& io_context, unsigned short port)
+    : acceptor_(io_context, {tcp::v4(), port})
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](std::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;
+    }
+
+    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;
+}