--- a/CMakeLists.txt	Wed Jun 01 17:09:12 2016 +0200
+++ b/CMakeLists.txt	Wed Jun 01 17:11:45 2016 +0200
@@ -49,4 +49,5 @@
 add_subdirectory(modules/ini)
 add_subdirectory(modules/js)
 add_subdirectory(modules/json)
+add_subdirectory(modules/net)
 add_subdirectory(modules/options)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/CMakeLists.txt	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,29 @@
+#
+# CMakeLists.txt -- code building for common code
+#
+# Copyright (c) 2013-2016 David Demelier <markand@malikania.fr>
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+
+find_package(OpenSSL)
+
+if (OPENSSL_FOUND)
+	code_define_module(
+		NAME net
+		SOURCES net.hpp
+		LIBRARIES $<$<BOOL:${WIN32}>:ws2_32> ${OPENSSL_LIBRARIES}
+		INCLUDES ${OPENSSL_INCLUDE_DIR}
+		FLAGS DIRECTORY=\"${CMAKE_CURRENT_SOURCE_DIR}/test/\"
+	)
+endif ()
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/doc/mainpage.cpp	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,57 @@
+/**
+ * @mainpage
+ *
+ * Welcome to the net library.
+ *
+ * ## Introduction
+ *
+ * Portable and convenient library for networking in C++14.
+ *
+ * ## What it is?
+ *
+ * A clean and portable set of classes and function wrapping the BSD sockets family. It provides an API as close as
+ * possible to the original BSD sockets functions.
+ *
+ * It is implemented using templates to make sockets as type safe as possible.
+ *
+ * This module also adds the following:
+ *
+ *   - Generic synchronous multiplexer based on select, poll, epoll and kqueue,
+ *   - Convenient object-oriented option system,
+ *   - Convenient object-oriented address system,
+ *   - Experimental [OpenSSL][] support.
+ *
+ * ## What it is not?
+ *
+ * This module is not a high-level network library. It does not add asynchronous stuff like [Boost.Asio][asio] does. It is
+ * targeted to people who like BSD sockets and want low level facilities. It only depends on C++11 standard library and
+ * optionally [OpenSSL][].
+ *
+ * ## Requirements
+ *
+ *   - C++11.
+ *   - OpenSSL, optional.
+ *
+ * ## Installation
+ *
+ * Just copy the file net.hpp and add it to your project.
+ *
+ * ## Overview
+ *
+ * ````
+ * #include "net.h"
+ *
+ * try {
+ *     net::SocketTcpIpv4 sc;
+ *
+ *     sc.bind(net::address::Ipv4("*", 8080));
+ *     sc.listen(64);
+ * } catch (const std::exception &ex) {
+ *     std::cerr << ex.what() << std::endl;
+ *     std::exit(1);
+ * }
+ * ````
+ *
+ * [asio]: http://www.boost.org/doc/libs/1_60_0/doc/html/boost_asio.html
+ * [OpenSSL]: http://openssl.org
+ */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/blocking-accept.cpp	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,52 @@
+/*
+ * blocking-accept.cpp -- example of blocking accept
+ *
+ * Options:
+ *   - WITH_PORT (int), the port to use (default: 16000)
+ *   - WITH_TIMEOUT (int), number of seconds before giving up (default: 60)
+ *   - WITH_SSL (bool), true to test with SSL (default: false)
+ */
+
+#include <iostream>
+
+#include "sockets.h"
+
+#if !defined(WITH_PORT)
+#  define WITH_PORT 16000
+#endif
+
+#if !defined(WITH_TIMEOUT)
+#  define WITH_TIMEOUT 60
+#endif
+
+int main()
+{
+#if defined(WITH_SSL)
+	net::SocketTls<net::address::Ip> master;
+	net::SocketTls<net::address::Ip> client{net::Invalid};
+#else
+	net::SocketTcp<net::address::Ip> master;
+	net::SocketTcp<net::address::Ip> client{net::Invalid};
+#endif
+
+	net::Listener<> listener;
+
+	try {
+		master.set(net::option::SockReuseAddress{true});
+		master.bind(net::address::Ip{"*", WITH_PORT});
+		master.listen();
+
+		listener.set(master.handle(), net::Condition::Readable);
+		listener.wait(std::chrono::seconds(WITH_TIMEOUT));
+
+		master.accept(client);
+	} catch (const net::Error &error) {
+		std::cerr << "error: " << error.what() << std::endl;
+		std::exit(1);
+	}
+
+	std::cout << "Client successfully accepted!" << std::endl;
+
+	return 0;	
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/blocking-connect.cpp	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,48 @@
+/*
+ * blocking-connect.cpp -- example of blocking connect
+ *
+ * Options:
+ *   - WITH_HOST (string literal), the host to try (default: "malikania.fr")
+ *   - WITH_PORT (int), the port to use (default: 80)
+ *   - WITH_TIMEOUT (int), number of seconds before giving up (default: 30)
+ *   - WITH_SSL (bool), true to test with SSL (default: false)
+ */
+
+#include <iostream>
+
+#if !defined(WITH_HOST)
+#  define WITH_HOST "malikania.fr"
+#endif
+
+#if !defined(WITH_PORT)
+#  define WITH_PORT 80
+#endif
+
+#if !defined(WITH_TIMEOUT)
+#  define WITH_TIMEOUT 30
+#endif
+
+#include "elapsed-timer.h"
+#include "sockets.h"
+
+int main()
+{
+#if defined(WITH_SSL)
+	net::SocketTls<net::address::Ipv4> socket;
+#else
+	net::SocketTcp<net::address::Ipv4> socket;
+#endif
+
+	try {
+		std::cout << "Trying to connect to " << WITH_HOST << ":" << WITH_PORT << std::endl;
+		socket.connect(net::address::Ip(WITH_HOST, WITH_PORT));
+	} catch (const net::Error &error) {
+		std::cerr << "error: " << error.what() << std::endl;
+		std::exit(1);
+	}
+
+	std::cout << "Successfully connected!" << std::endl;
+
+	return 0;
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/elapsed-timer.cpp	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,60 @@
+/*
+ * elapsed-timer.cpp -- measure elapsed time
+ *
+ * Copyright (c) 2013-2015 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "elapsed-timer.h"
+
+using std::chrono::duration_cast;
+using std::chrono::high_resolution_clock;
+using std::chrono::milliseconds;
+
+ElapsedTimer::ElapsedTimer() noexcept
+{
+	m_last = high_resolution_clock::now();
+}
+
+void ElapsedTimer::pause() noexcept
+{
+	/*
+	 * When we put the timer on pause, do not forget to set the already
+	 * elapsed time.
+	 */
+	(void)elapsed();
+	m_paused = true;
+}
+
+void ElapsedTimer::restart() noexcept
+{
+	m_paused = false;
+	m_last = high_resolution_clock::now();
+}
+
+void ElapsedTimer::reset() noexcept
+{
+	m_elapsed = 0;
+	m_last = high_resolution_clock::now();
+}
+
+unsigned ElapsedTimer::elapsed() noexcept
+{
+	if (!m_paused) {
+		m_elapsed += duration_cast<milliseconds>(high_resolution_clock::now() - m_last).count();
+		m_last = high_resolution_clock::now();
+	}
+
+	return m_elapsed;
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/elapsed-timer.h	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,77 @@
+/*
+ * elapsed-timer.h -- measure elapsed time
+ *
+ * Copyright (c) 2013-2015 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _ELAPSED_TIMER_H_
+#define _ELAPSED_TIMER_H_
+
+/**
+ * @file ElapsedTimer.h
+ * @brief Measure elapsed time
+ */
+
+#include <chrono>
+
+/**
+ * @class ElapsedTimer
+ * @brief Measure elapsed time
+ *
+ * This class provides an abstraction to measure elapsed time since the
+ * construction of the object.
+ *
+ * It uses std::chrono::high_resolution_clock for more precision and uses
+ * milliseconds only.
+ */
+class ElapsedTimer {
+public:
+	using TimePoint = std::chrono::time_point<std::chrono::high_resolution_clock>;
+
+private:
+	TimePoint m_last;
+	bool m_paused{false};
+	unsigned m_elapsed{0};
+
+public:
+	/**
+	 * Construct the elapsed timer, start counting.
+	 */
+	ElapsedTimer() noexcept;
+
+	/**
+	 * Put the timer on pause, the already elapsed time is stored.
+	 */
+	void pause() noexcept;
+
+	/**
+	 * Restart the timer, does not reset it.
+	 */
+	void restart() noexcept;
+
+	/**
+	 * Reset the timer to 0.
+	 */
+	void reset() noexcept;
+
+	/**
+	 * Get the number of elapsed milliseconds.
+	 *
+	 * @return the milliseconds
+	 */
+	unsigned elapsed() noexcept;
+};
+
+#endif // !_ELAPSED_TIMER_H_

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/non-blocking-accept.cpp	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,89 @@
+/*
+ * non-blocking-accept.cpp -- example of total non-blocking accept
+ *
+ * Options:
+ *   - WITH_PORT (int), the port to use (default: 16000)
+ *   - WITH_TIMEOUT (int), number of milliseconds before giving up (default: 3000)
+ *   - WITH_SSL (bool), true to test with SSL (default: false)
+ */
+
+#include <iostream>
+
+#include "elapsed-timer.h"
+#include "sockets.h"
+
+#if !defined(WITH_PORT)
+#  define WITH_PORT 16000
+#endif
+
+#if !defined(WITH_TIMEOUT)
+#  define WITH_TIMEOUT 3000
+#endif
+
+int main()
+{
+#if defined(WITH_SSL)
+	net::SocketTls<net::address::Ip> master;
+	net::SocketTls<net::address::Ip> client{net::Invalid};
+#else
+	net::SocketTcp<net::address::Ip> master;
+	net::SocketTcp<net::address::Ip> client{net::Invalid};
+#endif
+
+	net::Listener<> listener;
+	net::Condition cond;
+
+	ElapsedTimer timer;
+
+	// 1. Create the master socket for listening.
+	try {
+		master.set(net::option::SockReuseAddress{true});
+		master.set(net::option::SockBlockMode{false});
+		master.bind(net::address::Ip{"*", WITH_PORT});
+		master.listen();
+
+		listener.set(master.handle(), net::Condition::Readable);
+	} catch (const net::Error &error) {
+		std::cerr << "error: " << error.what() << std::endl;
+		std::exit(1);
+	}
+
+	while (!client.isOpen() && timer.elapsed() < WITH_TIMEOUT) {
+		try {
+			if (!client.isOpen()) {
+				// 2. Wait for a pre-accept process.
+				listener.wait(std::chrono::seconds(WITH_TIMEOUT));
+				master.accept(client, nullptr, &cond);
+				client.set(net::option::SockBlockMode(false));
+				listener.remove(master.handle());
+
+				std::cout << "Accepting new client" << std::endl;
+
+				if (cond != net::Condition::None) {
+					std::cout << "Client accept state not complete" << std::endl;
+					listener.set(client.handle(), cond);
+				}
+			} else {
+				// 3. Wait for the accept process to complete.
+				std::cout << "Continuing accept for the client" << std::endl;
+
+				listener.wait(std::chrono::seconds(WITH_TIMEOUT - timer.elapsed()));
+				client.accept(&cond);
+				listener.remove(client.handle());
+
+				if (cond != net::Condition::None) {
+					std::cout << "Client accept state not complete" << std::endl;
+					listener.set(client.handle(), cond);
+				}
+			}
+		} catch (const net::Error &error) {
+			std::cerr << error.function() << ": " << error.what() << std::endl;
+			std::exit(1);
+		}
+	}
+
+	if (client.isOpen())
+		std::cout << "Client successfully accepted!" << std::endl;
+
+	return 0;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/non-blocking-connect.cpp	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,65 @@
+/*
+ * non-blocking-connect.cpp -- example of non blocking connect
+ *
+ * Options:
+ *   - WITH_HOST (string literal), the host to try (default: "malikania.fr")
+ *   - WITH_PORT (int), the port to use (default: 80)
+ *   - WITH_TIMEOUT (int), number of milliseconds before giving up (default: 3000)
+ *   - WITH_SSL (bool), true to test with SSL (default: false)
+ */
+
+#include <iostream>
+
+#if !defined(WITH_HOST)
+#  define WITH_HOST "malikania.fr"
+#endif
+
+#if !defined(WITH_PORT)
+#  define WITH_PORT 80
+#endif
+
+#if !defined(WITH_TIMEOUT)
+#  define WITH_TIMEOUT 3000
+#endif
+
+#include "elapsed-timer.h"
+#include "sockets.h"
+
+int main()
+{
+#if defined(WITH_SSL)
+	net::SocketTls<net::address::Ip> socket;
+#else
+	net::SocketTcp<net::address::Ip> socket;
+#endif
+
+	net::Listener<> listener;
+	net::Condition cond;
+	ElapsedTimer timer;
+
+	// 1. Set to non-blocking.
+	socket.set(net::option::SockBlockMode(false));
+
+	try {
+		std::cout << "Trying to connect to " << WITH_HOST << ":" << WITH_PORT << std::endl;
+
+		// 2. Initial connection process.
+		socket.connect(net::address::Ip(WITH_HOST, WITH_PORT), &cond);
+
+		while (cond != net::Condition::None && timer.elapsed() < WITH_TIMEOUT) {
+			listener.remove(socket.handle());
+
+			// 2. Now complete by waiting for the appropriate condition.
+			listener.set(socket.handle(), cond);
+			listener.wait(std::chrono::milliseconds(WITH_TIMEOUT - timer.elapsed()));
+			socket.connect(&cond);
+		}
+	} catch (const net::Error &error) {
+		std::cerr << "error: " << error.what() << std::endl;
+		std::exit(1);
+	}
+
+	std::cout << "Successfully connected!" << std::endl;
+
+	return 0;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/test.crt	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,14 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/examples/test.key	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,15 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/net/net.hpp	Wed Jun 01 17:11:45 2016 +0200
@@ -0,0 +1,5052 @@
+/*
+ * net.hpp -- portable C++ socket wrappers
+ *
+ * Copyright (c) 2013-2016 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef NET_HPP
+#define NET_HPP
+
+/**
+ * \file net.hpp
+ * \brief Networking
+ * \author David Demelier <markand@malikania.fr>
+ */
+
+/**
+ * \defgroup net-module-tcp Network TCP support
+ * \brief TCP support in the networking module.
+ */
+
+/**
+ * \defgroup net-module-udp Network UDP support
+ * \brief UDP support in networking module.
+ */
+
+/**
+ * \defgroup net-module-tls Network TLS support
+ * \brief TLS support in networking module.
+ */
+
+/**
+ * \defgroup net-module-addresses Network predefined addresses
+ * \brief Predefined addresses for sockets
+ */
+
+/**
+ * \defgroup net-module-options Network predefined options
+ * \brief Predefined options for sockets
+ */
+
+/**
+ * \defgroup net-module-backends Network predefined backends
+ * \brief Predefined backends for Listener
+ */
+
+/**
+ * \defgroup net-module-resolv Network resolver
+ * \brief Resolv functions
+ */
+
+/**
+ * \page Networking Networking
+ *
+ *   - \subpage net-configuration
+ *   - \subpage net-options
+ *   - \subpage net-concepts
+ *   - \subpage net-examples
+ */
+
+/**
+ * \page net-configuration Configuration
+ *
+ * # General compatibility options.
+ *
+ * The following options are auto detected but you can override them if you want.
+ *
+ * - **NET_HAVE_INET_PTON**: (bool) Set to 1 if you have inet_pton function. True for all platforms and Windows
+ *   if _WIN32_WINNT is greater or equal to 0x0600.
+ *
+ * - **NET_HAVE_INET_NTOP**: (bool) Same as above.
+ *
+ * **Note:** On Windows, it is highly encouraged to set _WIN32_WINNT to at least 0x0600 on MinGW.
+ *
+ * # Options for Listener class
+ *
+ * Feature detection, multiple implementations may be avaible, for example, Linux has poll, select and epoll.
+ *
+ * We assume that `select(2)` is always available.
+ *
+ * Of course, you can set the variables yourself if you test it with your build system.
+ *
+ * - **NET_HAVE_POLL**: Defined on all BSD, Linux. Also defined on Windows
+ *   if _WIN32_WINNT is set to 0x0600 or greater.
+ *
+ * - **NET_HAVE_KQUEUE**: Defined on all BSD and Apple.
+ * - **NET_HAVE_EPOLL**: Defined on Linux only.
+ * - **NET_DEFAULT_BACKEND**: Which backend to use (e.g. `Select`).
+ *
+ * The preference priority is ordered from left to right.
+ *
+ * | System        | Backend                 | Class name   |
+ * |---------------|-------------------------|--------------|
+ * | Linux         | epoll(7)                | Epoll        |
+ * | *BSD          | kqueue(2)               | Kqueue       |
+ * | Windows       | poll(2), select(2)      | Poll, Select |
+ * | Mac OS X      | kqueue(2)               | Kqueue       |
+ */
+
+/**
+ * \page net-options User options
+ *
+ * The user may set the following variables before compiling these files:
+ *
+ * # General options
+ *
+ * - **NET_NO_AUTO_INIT**: (bool) Set to 0 if you don't want Socket class to
+ * automatically calls net::init function and net::finish functions.
+ *
+ * - **NET_NO_SSL**: (bool) Set to 0 if you don't have access to OpenSSL library.
+ *
+ * - **NET_NO_AUTO_SSL_INIT**: (bool) Set to 0 if you don't want Socket class with Tls to automatically init
+ *   the OpenSSL library. You will need to call net::ssl::init and net::ssl::finish.
+ */
+
+/**
+ * \page net-concepts Concepts
+ *
+ *   - \subpage net-concept-address
+ *   - \subpage net-concept-backend
+ *   - \subpage net-concept-option
+ *   - \subpage net-concept-stream
+ *   - \subpage net-concept-datagram
+ */
+
+/**
+ * \page net-concept-address Address (Concept)
+ *
+ * An address is used in many place for creating, binding, connecting, receiving and sending. They are implemented as
+ * templates to allow any type of address and to make sure the same address is used for a given socket.
+ *
+ * This concepts requires the following functions:
+ *
+ * # Address (constructor)
+ *
+ * The address must have the following constructor overloads.
+ *
+ * **Note**: the user can add custom constructors.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * Address(); // (0);
+ * Address(const sockaddr *sa, socklen_t length); // (1)
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **ss**: the storage to construct from,
+ *   - **length**: the storage length.
+ *
+ * # domain
+ *
+ * Get the domain (e.g. AF_INET).
+ *
+ * ## Synopsis
+ *
+ * ````
+ * int domain() const noexcept;
+ * ````
+ *
+ * ## Returns
+ *
+ * The domain.
+ *
+ * # address
+ *
+ * Get the underlying address.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * const sockaddr *address() const noexcept;
+ * ````
+ *
+ * ## Returns
+ *
+ * The address.
+ *
+ * # length
+ *
+ * Get the underlying length.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * socklen_t length() const noexcept;
+ * ````
+ *
+ * ## Returns
+ *
+ * The length.
+ */
+
+/**
+ * \page net-concept-backend Backend (Concept)
+ *
+ * A backend is an interface for the Listener class. It is primarily designed to be the most suitable for the host
+ * environment.
+ *
+ * The backend must be default constructible, it is highly encouraged to be move constructible.
+ *
+ * This concepts requires the following functions:
+ *
+ * # name
+ *
+ * Get the backend name, informational only.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * std::string name() const;
+ * ````
+ *
+ * ## Returns
+ *
+ * The backend name.
+ *
+ * # set
+ *
+ * Set one or more condition for the given handle.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * void set(const ListenerTable &table, Handle handle, Condition condition, bool add);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **table**: the current table of sockets,
+ *   - **handle**: the handle to set,
+ *   - **condition**: the condition to add (may be OR'ed),
+ *   - **add**: hint set to true if the handle is not currently registered at all.
+ *
+ * # unset
+ *
+ * Unset one or more condition for the given handle.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * void unset(const ListenerTable &table, Handle handle, Condition condition, bool remove);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **table**: the current table of sockets,
+ *   - **handle**: the handle to update,
+ *   - **condition**: the condition to remove (may be OR'ed),
+ *   - **remove**: hint set to true if the handle will be completely removed.
+ *
+ * # wait
+ *
+ * Wait for multiple sockets to be ready.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * std::vector<ListenerStatus> wait(const ListenerTable &table, int ms);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **table**: the current table,
+ *   - **ms**: the number to wait in milliseconds, negative means forever.
+ *
+ * ## Returns
+ *
+ * The list of sockets ready paired to their condition.
+ */
+
+/**
+ * \page net-concept-option Option (Concept)
+ *
+ * An option can be set or get from a socket.
+ *
+ * If an operation is not available, provides the function but throws an exception with ENOSYS errno code.
+ *
+ * This concepts requires the following functions:
+ *
+ * # Option (constructor)
+ *
+ * At least one default constructor must be present.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * Option() noexcept;
+ * ````
+ *
+ * # set
+ *
+ * Set the option.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * inline void set(Socket<Address, Protocol> &sc) const;
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket.
+ *
+ * # get
+ *
+ * Get an option, T can be any type.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * inline bool get(Socket<Address, Protocol> &sc) const;
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket.
+ *
+ * ## Returns
+ *
+ * The value.
+ */
+
+/**
+ * \page net-concept-stream Stream (Concept)
+ *
+ * This concepts requires the following functions:
+ *
+ * # type
+ *
+ * Return the type of socket, usually `SOCK_STREAM`.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * int type() const noexcept;
+ * ````
+ *
+ * ## Returns
+ *
+ * The type of socket.
+ *
+ * # create
+ *
+ * Function called immediately after creation of socket. Interface must provides this function even if the
+ * interface does not require anything.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address>
+ * void create(Socket<Address, Tcp> &) const noexcept;
+ * ````
+ *
+ * # connect
+ *
+ * Initial connect function.
+ *
+ * In this function, the interface receive the socket, address and a condition (initially set to None). If the
+ * underlying socket is marked non-blocking and the operation would block, the interface must set the condition
+ * to the required one.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * void connect(Socket<Address, Protocol> &sc, const sockaddr *address, socklen_t length, Condition &cond);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **address**: the address,
+ *   - **length**: the address length,
+ *   - **cond**: the condition to update.
+ *
+ * # resumeConnect
+ *
+ * Continue the connection.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * void resumeConnect(Socket<Address, Protocol> &sc, Condition &cond)
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **cond**: the condition to update.
+ *
+ * # accept
+ *
+ * Accept a new client.
+ *
+ * If the interface has no pending connection, an invalid socket SHOULD be returned, otherwise return the client and
+ * set the condition if the accept process is not complete yet.
+ *
+ * The interface MUST stores the client information into address and length parameters, they are guaranted to never be
+ * null.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * Socket<Address, Protocol> accept(Socket<Address, Protocol> &sc, sockaddr *address, socklen_t *length, Condition &cond);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **address**: the information address,
+ *   - **length**: the address initial length (sockaddr_storage),
+ *   - **cond**: the condition to update.
+ *
+ * # resumeAccept
+ *
+ * Continue the accept process on the returned client.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * void accept(Socket<Address, Protocol> &sc, Condition &cond) const noexcept;
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **cond**: the condition to update.
+ *
+ * # recv
+ *
+ * Receive data.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address>
+ * std::size_t recv(Socket<Address, Tcp> &sc, void *data, std::size_t length, Condition &cond);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **data**: the destination buffer,
+ *   - **length**: the destination buffer length,
+ *   - **cond**: the condition to update.
+ *
+ * ## Returns
+ *
+ * The number of bytes sent.
+ *
+ * # send
+ *
+ * Send data.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address>
+ * std::size_t send(Socket<Address, Tcp> &sc, const void *data, std::size_t length, Condition &cond);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **data**: the data to send,
+ *   - **length**: the data length,
+ *   - **cond**: the condition to update.
+ *
+ * ## Returns
+ *
+ * The number of bytes sent.
+ */
+
+/**
+ * \page net-concept-datagram Datagram (Concept)
+ *
+ * This concepts requires the following functions:
+ *
+ * # type
+ *
+ * Return the type of socket, usually `SOCK_DGRAM`.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * int type() const noexcept;
+ * ````
+ *
+ * ## Returns
+ *
+ * The type of socket.
+ *
+ * # recvfrom
+ *
+ * Receive data.
+ *
+ * ## Synopsis
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * std::size_t recvfrom(Socket<Address, Protocol> &sc, void *data, std::size_t length, sockaddr *address, socklen_t *addrlen, Condition &cond);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **data**: the data,
+ *   - **length**: the length,
+ *   - **address**: the source address,
+ *   - **addrlen**: the source address in/out length,
+ *   - **cond**: the condition.
+ *
+ * ## Returns
+ *
+ * The number of bytes received.
+ *
+ * # sendto
+ *
+ * ````
+ * template <typename Address, typename Protocol>
+ * std::size_t sendto(Socket<Address, Protocol> &sc, const void *data, std::size_t length, const sockaddr *address, socklen_t addrlen, Condition &cond);
+ * ````
+ *
+ * ## Arguments
+ *
+ *   - **sc**: the socket,
+ *   - **data**: the data to send,
+ *   - **length**: the data length,
+ *   - **address**: the destination address,
+ *   - **addrlen**: the destination address length,
+ *   - **cond**: the condition.
+ *
+ * ## Returns
+ *
+ * The number of bytes sent.
+ */
+
+/**
+ * \page net-examples Examples
+ *
+ * # Non blocking examples
+ *
+ * Non-blocking sockets can be tedious, here various examples on how to do it with this module.
+ *
+ *   - \subpage net-example-non-blocking-connect
+ */
+
+/**
+ * \page net-example-non-blocking-connect Non-blocking connect
+ *
+ * This example shows how to make a non-blocking connect.
+ *
+ * Because SSL support is first class value, the connection functions are a bit more tricky but don't be afraid it is completely
+ * transparent for the user.
+ *
+ * ## Background
+ *
+ * First, let's explain what usually happen in traditional fashion.
+ *
+ * When you use the connect(2) function in a non-blocking socket, EINPROGRESS is returned if the connection could not be immediately
+ * established, the user must then wait until the socket is writable and check for SOL_SOCKET/SO_ERROR option. For OpenSSL, user must wait
+ * for readable/writable depending on the current operation, remember that OpenSSL requires several roundtrips to finalize handshake.
+ *
+ * Because these operations are different on TCP and SSL sockets, the Socket class has a unique resumeConnect function which have a
+ * different implementation depending if the socket is SSL or raw TCP. Also because resumeConnect() must be called only when the socket is
+ * either readable or writable, a condition is given to the user in several function including Socket::connect().
+ *
+ * ## Code
+ *
+ * In this code, we will try to connect to example.org on port 9090 using TCP/IPv4.
+ *
+ * ````cpp
+ * #include <iostream>
+ *
+ * #include "net.hpp"
+ *
+ * void connect(net::SocketTcpIpv4 &sc)
+ * {
+ *   // (0) The listener, used to wait for a condition.
+ *   net::Listener<> listener;
+ *
+ *   // (1) The condition that we must wait for, no need to initialize.
+ *   net::Condition cond;
+ *
+ *   // (2) Do the initial connection attempt
+ *   //
+ *   // If cond != net::Condition::None, the connection was unable to complete immediately.
+ *   sc.connect(net::address::Ipv4::resolve("example.org", "9090"), cond);
+ *
+ *   while (cond != net::Condition::None) {
+ *     // (3) Erase the previous condition.
+ *     listener.remove(sc.handle());
+ *
+ *     // (4) Add the requested condition.
+ *     listener.set(sc.handle(), cond);
+ *
+ *     // (5) Wait and try to resume the condition, don't forget to give cond again.
+ *     listener.wait();
+ *     sc.resumeConnect(cond);
+ *   }
+ * }
+ *
+ * int main()
+ * {
+ *   try {
+ *     net::SocketTcpIpv4 sc;
+ *
+ *     // Set the socket non-blocking.
+ *     sc.set(net::option::SockBlockMode(false));
+ *
+ *     connect(sc);
+ *   } catch (const std::exception &ex) {
+ *     std::cerr << ex.what() << std::endl;
+ *     return 1;
+ *   }
+ *
+ *   return 0;
+ * }
+ * ````
+ */
+
+/*
+ * Headers to include.
+ * ------------------------------------------------------------------
+ */
+
+// Include Windows headers before because it brings _WIN32_WINNT if not specified by the user.
+#if defined(_WIN32)
+#  include <WinSock2.h>
+#  include <WS2tcpip.h>
+#else
+#  include <sys/ioctl.h>
+#  include <sys/types.h>
+#  include <sys/socket.h>
+#  include <sys/un.h>
+
+#  include <arpa/inet.h>
+
+#  include <netinet/in.h>
+#  include <netinet/tcp.h>
+
+#  include <fcntl.h>
+#  include <netdb.h>
+#  include <unistd.h>
+#endif
+
+#include <algorithm>
+#include <atomic>
+#include <cassert>
+#include <cerrno>
+#include <chrono>
+#include <climits>
+#include <cstddef>
+#include <cstdlib>
+#include <cstring>
+#include <iterator>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#if !defined(NET_NO_SSL)
+
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/ssl.h>
+
+#endif // !NET_NO_SSL
+
+/*
+ * Determine which I/O multiplexing implementations are available.
+ * ------------------------------------------------------------------
+ *
+ * May define the following:
+ *
+ *   - NET_HAVE_EPOLL
+ *   - NET_HAVE_KQUEUE
+ *   - NET_HAVE_POLL
+ */
+
+#if defined(_WIN32)
+#  if _WIN32_WINNT >= 0x0600 && !defined(NET_HAVE_POLL)
+#    define NET_HAVE_POLL
+#  endif
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
+#  if !defined(NET_HAVE_KQUEUE)
+#    define NET_HAVE_KQUEUE
+#  endif
+#  if !defined(NET_HAVE_POLL)
+#    define NET_HAVE_POLL
+#  endif
+#elif defined(__linux__)
+#  if !defined(NET_HAVE_EPOLL)
+#    define NET_HAVE_EPOLL
+#  endif
+#  if !defined(NET_HAVE_POLL)
+#    define NET_HAVE_POLL
+#  endif
+#endif
+
+/*
+ * Compatibility macros.
+ * ------------------------------------------------------------------
+ */
+
+/**
+ * \brief Tells if inet_pton is available
+ */
+#if !defined(NET_HAVE_INET_PTON)
+#  if defined(_WIN32)
+#    if _WIN32_WINNT >= 0x0600
+#      define NET_HAVE_INET_PTON
+#    endif
+#  else
+#    define NET_HAVE_INET_PTON
+#  endif
+#endif
+
+/**
+ * \brief Tells if inet_ntop is available
+ */
+#if !defined(NET_HAVE_INET_NTOP)
+#  if defined(_WIN32)
+#    if _WIN32_WINNT >= 0x0600
+#      define NET_HAVE_INET_NTOP
+#    endif
+#  else
+#    define NET_HAVE_INET_NTOP
+#  endif
+#endif
+
+/*
+ * Define NET_DEFAULT_BACKEND.
+ * ------------------------------------------------------------------
+ *
+ * Define the default I/O multiplexing implementation to use if not specified.
+ */
+
+/**
+ * \brief Defines the default backend
+ */
+#if defined(_WIN32)
+#  if !defined(NET_DEFAULT_BACKEND)
+#    if defined(NET_HAVE_POLL)
+#      define NET_DEFAULT_BACKEND Poll
+#    else
+#      define NET_DEFAULT_BACKEND Select
+#    endif
+#  endif
+#elif defined(__linux__)
+#  include <sys/epoll.h>
+
+#  if !defined(NET_DEFAULT_BACKEND)
+#    define NET_DEFAULT_BACKEND Epoll
+#  endif
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__) || defined(__APPLE__)
+#  include <sys/types.h>
+#  include <sys/event.h>
+#  include <sys/time.h>
+
+#  if !defined(NET_DEFAULT_BACKEND)
+#    define NET_DEFAULT_BACKEND Kqueue
+#  endif
+#else
+#  if !defined(NET_DEFAULT_BACKEND)
+#    define NET_DEFAULT_BACKEND Select
+#  endif
+#endif
+
+#if defined(NET_HAVE_POLL) && !defined(_WIN32)
+#  include <poll.h>
+#endif
+
+/**
+ * The network namespace.
+ */
+namespace net {
+
+/*
+ * Portables types.
+ * ------------------------------------------------------------------
+ *
+ * The following types are defined differently between Unix and Windows.
+ */
+
+#if defined(_WIN32)
+
+/**
+ * Socket type, SOCKET.
+ */
+using Handle = SOCKET;
+
+/**
+ * Argument to pass to set.
+ */
+using ConstArg = const char *;
+
+/**
+ * Argument to pass to get.
+ */
+using Arg = char *;
+
+#else
+
+/**
+ * Socket type, int.
+ */
+using Handle = int;
+
+/**
+ * Argument to pass to set.
+ */
+using ConstArg = const void *;
+
+/**
+ * Argument to pass to get.
+ */
+using Arg = void *;
+
+#endif
+
+/*
+ * Portable constants.
+ * ------------------------------------------------------------------
+ *
+ * These constants are needed to check functions return codes, they are rarely needed in end user code.
+ */
+
+#if defined(_WIN32)
+
+/**
+ * Socket creation failure or invalidation.
+ */
+const Handle Invalid{INVALID_SOCKET};
+
+/**
+ * Socket operation failure.
+ */
+const int Failure{SOCKET_ERROR};
+
+#else
+
+/**
+ * Socket creation failure or invalidation.
+ */
+const Handle Invalid{-1};
+
+/**
+ * Socket operation failure.
+ */
+const int Failure{-1};
+
+#endif
+
+/**
+ * Close the socket library.
+ */
+inline void finish() noexcept
+{
+#if defined(_WIN32)
+	WSACleanup();
+#endif
+}
+
+/**
+ * Initialize the socket library. Except if you defined NET_NO_AUTO_INIT, you don't need to call this
+ * function manually.
+ */
+inline void init() noexcept
+{
+#if defined(_WIN32)
+	static std::atomic<bool> initialized;
+	static std::mutex mutex;
+
+	std::lock_guard<std::mutex> lock(mutex);
+
+	if (!initialized) {
+		initialized = true;
+
+		WSADATA wsa;
+		WSAStartup(MAKEWORD(2, 2), &wsa);
+
+		// If NET_NO_AUTO_INIT is not set then the user must also call finish himself.
+#if !defined(NET_NO_AUTO_INIT)
+		atexit(finish);
+#endif
+	}
+#endif
+}
+
+/**
+ * Get the last system error.
+ *
+ * \param errn the error number (errno or WSAGetLastError)
+ * \return the error
+ */
+inline std::string error(int errn)
+{
+#if defined(_WIN32)
+	LPSTR str = nullptr;
+	std::string errmsg = "Unknown error";
+
+	FormatMessageA(
+		FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
+		NULL,
+		errn,
+		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+		(LPSTR)&str, 0, NULL);
+
+
+	if (str) {
+		errmsg = std::string(str);
+		LocalFree(str);
+	}
+
+	return errmsg;
+#else
+	return strerror(errn);
+#endif
+}
+
+/**
+ * Get the last socket system error. The error is set from errno or from WSAGetLastError on Windows.
+ *
+ * \return a string message
+ */
+inline std::string error()
+{
+#if defined(_WIN32)
+	return error(WSAGetLastError());
+#else
+	return error(errno);
+#endif
+}
+
+#if !defined(NET_NO_SSL)
+
+/**
+ * \brief SSL namespace
+ */
+namespace ssl {
+
+/**
+ * \enum Method
+ * \brief Which OpenSSL method to use.
+ */
+enum Method {
+	Tlsv1,		//!< TLS v1.2 (recommended)
+	Sslv3		//!< SSLv3
+};
+
+/**
+ * Initialize the OpenSSL library. Except if you defined NET_NO_AUTO_SSL_INIT, you don't need to call this function
+ * manually.
+ */
+inline void init() noexcept
+{
+	static std::atomic<bool> initialized;
+	static std::mutex mutex;
+
+	std::lock_guard<std::mutex> lock(mutex);
+
+	if (!initialized) {
+		initialized = true;
+
+		SSL_library_init();
+		SSL_load_error_strings();
+		OpenSSL_add_all_algorithms();
+
+#if !defined(NET_NO_AUTO_SSL_INIT)
+		atexit(finish);
+#endif
+	}
+}
+
+/**
+ * Close the OpenSSL library.
+ */
+inline void finish() noexcept
+{
+	ERR_free_strings();
+}
+
+} // !ssl
+
+#endif // !NET_NO_SSL
+
+/*
+ * Error class.
+ * ------------------------------------------------------------------
+ *
+ * This is the main exception thrown on socket operations.
+ */
+
+/**
+ * \brief Base class for sockets error
+ */
+class Error : public std::exception {
+public:
+	/**
+	 * \enum Code
+	 * \brief Which kind of error
+	 */
+	enum Code {
+		Timeout,		///!< The action did timeout
+		System,			///!< There is a system error
+		Other			///!< Other custom error
+	};
+
+private:
+	Code m_code;
+	std::string m_function;
+	std::string m_error;
+
+public:
+	/**
+	 * Constructor that use the last system error.
+	 *
+	 * \param code which kind of error
+	 * \param function the function name
+	 */
+	inline Error(Code code, std::string function)
+		: m_code(code)
+		, m_function(std::move(function))
+		, m_error(error())
+	{
+	}
+
+	/**
+	 * Constructor that use the system error set by the user.
+	 *
+	 * \param code which kind of error
+	 * \param function the function name
+	 * \param n the error
+	 */
+	inline Error(Code code, std::string function, int n)
+		: m_code(code)
+		, m_function(std::move(function))
+		, m_error(error(n))
+	{
+	}
+
+	/**
+	 * Constructor that set the error specified by the user.
+	 *
+	 * \param code which kind of error
+	 * \param function the function name
+	 * \param error the error
+	 */
+	inline Error(Code code, std::string function, std::string error)
+		: m_code(code)
+		, m_function(std::move(function))
+		, m_error(std::move(error))
+	{
+	}
+
+	/**
+	 * Get which function has triggered the error.
+	 *
+	 * \return the function name (e.g connect)
+	 */
+	inline const std::string &function() const noexcept
+	{
+		return m_function;
+	}
+
+	/**
+	 * The error code.
+	 *
+	 * \return the code
+	 */
+	inline Code code() const noexcept
+	{
+		return m_code;
+	}
+
+	/**
+	 * Get the error (only the error content).
+	 *
+	 * \return the error
+	 */
+	const char *what() const noexcept override
+	{
+		return m_error.c_str();
+	}
+};
+
+/*
+ * Condition enum
+ * ------------------------------------------------------------------
+ *
+ * Defines if we must wait for reading or writing.
+ */
+
+/**
+ * \enum Condition
+ * \brief Define the required condition for the socket.
+ *
+ * As explained in Action enumeration, some operations required to be called several times, before calling these
+ * operations, the user must wait the socket to be readable or writable. This can be checked with Socket::condition.
+ */
+enum class Condition {
+	None,			//!< No condition is required
+	Readable = (1 << 0),	//!< The socket must be readable
+	Writable = (1 << 1)	//!< The socket must be writable
+};
+
+/**
+ * Apply bitwise XOR.
+ *
+ * \param v1 the first value
+ * \param v2 the second value
+ * \return the new value
+ */
+inline Condition operator^(Condition v1, Condition v2) noexcept
+{
+	return static_cast<Condition>(static_cast<int>(v1) ^ static_cast<int>(v2));
+}
+
+/**
+ * Apply bitwise AND.
+ *
+ * \param v1 the first value
+ * \param v2 the second value
+ * \return the new value
+ */
+inline Condition operator&(Condition v1, Condition v2) noexcept
+{
+	return static_cast<Condition>(static_cast<int>(v1) & static_cast<int>(v2));
+}
+
+/**
+ * Apply bitwise OR.
+ *
+ * \param v1 the first value
+ * \param v2 the second value
+ * \return the new value
+ */
+inline Condition operator|(Condition v1, Condition v2) noexcept
+{
+	return static_cast<Condition>(static_cast<int>(v1) | static_cast<int>(v2));
+}
+
+/**
+ * Apply bitwise NOT.
+ *
+ * \param v the value
+ * \return the complement
+ */
+inline Condition operator~(Condition v) noexcept
+{
+	return static_cast<Condition>(~static_cast<int>(v));
+}
+
+/**
+ * Assign bitwise OR.
+ *
+ * \param v1 the first value
+ * \param v2 the second value
+ * \return the new value
+ */
+inline Condition &operator|=(Condition &v1, Condition v2) noexcept
+{
+	v1 = static_cast<Condition>(static_cast<int>(v1) | static_cast<int>(v2));
+
+	return v1;
+}
+
+/**
+ * Assign bitwise AND.
+ *
+ * \param v1 the first value
+ * \param v2 the second value
+ * \return the new value
+ */
+inline Condition &operator&=(Condition &v1, Condition v2) noexcept
+{
+	v1 = static_cast<Condition>(static_cast<int>(v1) & static_cast<int>(v2));
+
+	return v1;
+}
+
+/**
+ * Assign bitwise XOR.
+ *
+ * \param v1 the first value
+ * \param v2 the second value
+ * \return the new value
+ */
+inline Condition &operator^=(Condition &v1, Condition v2) noexcept
+{
+	v1 = static_cast<Condition>(static_cast<int>(v1) ^ static_cast<int>(v2));
+
+	return v1;
+}
+
+/*
+ * Base Socket class
+ * ------------------------------------------------------------------
+ *
+ * This base class has operations that are common to all types of sockets but you usually instanciate
+ * a SocketTcp or SocketUdp
+ */
+
+/**
+ * \brief Base socket class for socket operations.
+ *
+ * **Important:** When using non-blocking sockets, some considerations must be taken. See the implementation of the
+ * underlying protocol for more details.
+ *
+ * When using non-blocking sockets, it is important to pass the condition to functions which may block, they indicate
+ * the condition to wait to perform or continue the operation if they would block.
+ *
+ * For example, when trying to connect with non-blocking, user should do the following:
+ *
+ * 1. Call Socket::connect() with the condition,
+ * 2. Loop until condition is not set to Condition::None (or an exception is thrown),
+ * 3. Wait with a listener for the condition to be ready (see Listener::wait),
+ * 4. Call Socket::resumeConnect() with the condition again.
+ *
+ * \see protocol::Tls
+ * \see protocol::Tcp
+ * \see protocol::Udp
+ */
+template <typename Address, typename Protocol>
+class Socket {
+private:
+	Protocol m_proto;
+
+protected:
+	/**
+	 * The native handle.
+	 */
+	Handle m_handle{Invalid};
+
+public:
+	/**
+	 * Create a socket handle.
+	 *
+	 * This is the primary function and the only one that creates the socket handle, all other constructors
+	 * are just overloaded functions.
+	 *
+	 * \param domain the domain AF_*
+	 * \param type the type SOCK_*
+	 * \param protocol the protocol
+	 * \param iface the implementation
+	 * \throw net::Error on errors
+	 */
+	Socket(int domain, int type, int protocol, Protocol iface = {})
+		: m_proto(std::move(iface))
+	{
+#if !defined(NET_NO_AUTO_INIT)
+		init();
+#endif
+		m_handle = ::socket(domain, type, protocol);
+
+		if (m_handle == Invalid)
+			throw Error(Error::System, "socket");
+
+		m_proto.create(*this);
+	}
+
+	/**
+	 * This tries to create a socket.
+	 *
+	 * Domain and type are determined by the Address and Protocol object.
+	 *
+	 * \param address which type of address
+	 * \param protocol the protocol
+	 * \throw net::Error on errors
+	 */
+	explicit inline Socket(const Address &address = {}, Protocol protocol = {})
+		: Socket(address.domain(), protocol.type(), 0, std::move(protocol))
+	{
+	}
+
+	/**
+	 * Create the socket with an already defined handle and its protocol.
+	 *
+	 * \param handle the handle
+	 * \param protocol the protocol
+	 */
+	explicit inline Socket(Handle handle, Protocol protocol = {}) noexcept
+		: m_proto(std::move(protocol))
+		, m_handle(handle)
+	{
+	}
+
+	/**
+	 * Create an invalid socket. Can be used when you cannot instanciate the socket immediately.
+	 */
+	explicit inline Socket(std::nullptr_t) noexcept
+		: m_handle(Invalid)
+	{
+	}
+
+	/**
+	 * Copy constructor deleted.
+	 */
+	Socket(const Socket &) = delete;
+
+	/**
+	 * Transfer ownership from other to this.
+	 *
+	 * \param other the other socket
+	 */
+	inline Socket(Socket &&other) noexcept
+		: m_proto(std::move(other.m_proto))
+		, m_handle(other.m_handle)
+	{
+		other.m_handle = Invalid;
+	}
+
+	/**
+	 * Default destructor.
+	 */
+	virtual ~Socket()
+	{
+		close();
+	}
+
+	/**
+	 * Access the implementation.
+	 *
+	 * \return the implementation
+	 * \warning use this function with care
+	 */
+	inline const Protocol &protocol() const noexcept
+	{
+		return m_proto;
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \return the implementation
+	 */
+	inline Protocol &protocol() noexcept
+	{
+		return m_proto;
+	}
+
+	/**
+	 * Tells if the socket is not invalid.
+	 *
+	 * \return true if not invalid
+	 */
+	inline bool isOpen() const noexcept
+	{
+		return m_handle != Invalid;
+	}
+
+	/**
+	 * Set an option for the socket. Wrapper of setsockopt(2).
+	 *
+	 * \pre isOpen()
+	 * \param level the setting level
+	 * \param name the name
+	 * \param arg the value
+	 * \throw net::Error on errors
+	 */
+	template <typename Argument>
+	inline void set(int level, int name, const Argument &arg)
+	{
+		assert(m_handle != Invalid);
+
+		if (setsockopt(m_handle, level, name, (ConstArg)&arg, sizeof (arg)) == Failure)
+			throw Error(Error::System, "set");
+	}
+
+	/**
+	 * Object-oriented option setter.
+	 *
+	 * The object must have `set(Socket<Address, Protocol> &) const`.
+	 *
+	 * \pre isOpen()
+	 * \param option the option
+	 * \throw net::Error on errors
+	 */
+	template <typename Option>
+	inline void set(const Option &option)
+	{
+		assert(m_handle != Invalid);
+
+		option.set(*this);
+	}
+
+	/**
+	 * Get an option for the socket. Wrapper of getsockopt(2).
+	 *
+	 * \pre isOpen()
+	 * \param level the setting level
+	 * \param name the name
+	 * \return the value
+	 * \throw net::Error on errors
+	 */
+	template <typename Argument>
+	Argument get(int level, int name)
+	{
+		assert(m_handle != Invalid);
+
+		Argument desired, result{};
+		socklen_t size = sizeof (result);
+
+		if (getsockopt(m_handle, level, name, (Arg)&desired, &size) == Failure)
+			throw Error(Error::System, "get");
+
+		std::memcpy(&result, &desired, size);
+
+		return result;
+	}
+
+	/**
+	 * Object-oriented option getter.
+	 *
+	 * The object must have `T get(Socket<Address, Protocol> &) const`, T can be any type and it is the value
+	 * returned from this function.
+	 *
+	 * \pre isOpen()
+	 * \return the same value as get() in the option
+	 * \throw net::Error on errors
+	 */
+	template <typename Option>
+	inline auto get() -> decltype(std::declval<Option>().get(*this))
+	{
+		assert(m_handle != Invalid);
+
+		return Option().get(*this);
+	}
+
+	/**
+	 * Get the native handle.
+	 *
+	 * \return the handle
+	 * \warning Not portable
+	 */
+	inline Handle handle() const noexcept
+	{
+		return m_handle;
+	}
+
+	/**
+	 * Bind using a native address.
+	 *
+	 * \pre isOpen()
+	 * \param address the address
+	 * \param length the size
+	 * \throw net::Error on errors
+	 */
+	inline void bind(const sockaddr *address, socklen_t length)
+	{
+		assert(m_handle != Invalid);
+
+		if (::bind(m_handle, address, length) == Failure)
+			throw Error(Error::System, "bind");
+	}
+
+	/**
+	 * Overload that takes an address.
+	 *
+	 * \pre isOpen()
+	 * \param address the address
+	 * \throw net::Error on errors
+	 */
+	inline void bind(const Address &address)
+	{
+		assert(m_handle != Invalid);
+
+		if (::bind(m_handle, address.address(), address.length()) == Failure)
+			throw Error(Error::System, "bind");
+	}
+
+	/**
+	 * Listen for pending connection.
+	 *
+	 * \pre isOpen()
+	 * \param max the maximum number
+	 * \throw net::Error on errors
+	 */
+	inline void listen(int max = 128)
+	{
+		assert(m_handle != Invalid);
+
+		if (::listen(this->m_handle, max) == Failure)
+			throw Error(Error::System, "listen");
+	}
+
+	/**
+	 * Get the local name. This is a wrapper of getsockname().
+	 *
+	 * \pre isOpen()
+	 * \return the address
+	 * \throw Error on failures
+	 */
+	Address getsockname() const
+	{
+		assert(m_handle != Invalid);
+
+		sockaddr_storage ss;
+		socklen_t length = sizeof (sockaddr_storage);
+
+		if (::getsockname(m_handle, reinterpret_cast<sockaddr *>(&ss), &length) == Failure)
+			throw Error(Error::System, "getsockname");
+
+		return Address(reinterpret_cast<sockaddr *>(&ss), length);
+	}
+
+	/**
+	 * Get connected address. This is a wrapper for getpeername().
+	 *
+	 * \pre isOpen()
+	 * \return the address
+	 * \throw Error on failures
+	 */
+	Address getpeername() const
+	{
+		assert(m_handle != Invalid);
+
+		sockaddr_storage ss;
+		socklen_t length = sizeof (sockaddr_storage);
+
+		if (::getpeername(m_handle, reinterpret_cast<sockaddr *>(&ss), &length) == Failure)
+			throw Error(Error::System, "getpeername");
+
+		return Address(reinterpret_cast<sockaddr *>(&ss), length);
+	}
+
+	/**
+	 * Initialize connection to the given address.
+	 *
+	 * \pre isOpen()
+	 * \param address the address
+	 * \param length the address length
+	 * \param cond the condition
+	 * \throw net::Error on failures
+	 */
+	inline void connect(const sockaddr *address, socklen_t length, Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		cond = Condition::None;
+
+		m_proto.connect(*this, address, length, cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param address the address
+	 * \param length the address length
+	 * \throw net::Error on failures
+	 */
+	inline void connect(const sockaddr *address, socklen_t length)
+	{
+		Condition dummy;
+
+		connect(address, length, dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param address the address
+	 * \param cond the condition
+	 * \throw net::Error on failures
+	 */
+	inline void connect(const Address &address, Condition &cond)
+	{
+		connect(address.address(), address.length(), cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param address the address
+	 * \throw net::Error on failures
+	 */
+	inline void connect(const Address &address)
+	{
+		Condition dummy;
+
+		connect(address.address(), address.length(), dummy);
+	}
+
+	/**
+	 * Continue connect process.
+	 *
+	 * \pre isOpen()
+	 * \param cond the condition require for next selection
+	 * \throw net::Error on failures
+	 */
+	inline void resumeConnect(Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		cond = Condition::None;
+
+		m_proto.resumeConnect(*this, cond);
+	}
+
+	/**
+	 * Continue connect process.
+	 *
+	 * \pre isOpen()
+	 * \throw net::Error on failures
+	 */
+	inline void resumeConnect()
+	{
+		Condition dummy;
+
+		resumeConnect(dummy);
+	}
+
+	/**
+	 * Accept a new client.
+	 *
+	 * If no connection is available immediately, returns an invalid socket.
+	 *
+	 * \pre isOpen()
+	 * \param address the client information
+	 * \param cond the condition to wait to complete accept on the **client**
+	 * \return the new client or an invalid if no client is immediately available
+	 * \throw net::Error on failures
+	 */
+	Socket<Address, Protocol> accept(Address &address, Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		sockaddr_storage storage;
+		socklen_t length = sizeof (storage);
+
+		cond = Condition::None;
+
+		Socket<Address, Protocol> client = m_proto.accept(*this, reinterpret_cast<sockaddr *>(&storage), &length, cond);
+
+		address = Address(reinterpret_cast<sockaddr *>(&storage), length);
+
+		return client;
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param address the client information
+	 * \return the new client or an invalid if no client is immediately available
+	 * \throw net::Error on failures
+	 */
+	inline Socket<Address, Protocol> accept(Address &address)
+	{
+		Condition dummy;
+
+		return accept(address, dummy);
+	}
+
+	/**
+	 * Overlaoded function.
+	 *
+	 * \pre isOpen()
+	 * \return the new client or an invalid if no client is immediately available
+	 * \throw net::Error on failures
+	 */
+	inline Socket<Address, Protocol> accept()
+	{
+		Address da;
+		Condition dc;
+
+		return accept(da, dc);
+	}
+
+	/**
+	 * Continue accept process.
+	 *
+	 * \pre isOpen()
+	 * \param cond the condition
+	 * \throw net::Error on failures
+	 * \note This should be called on the returned client from accept
+	 */
+	inline void resumeAccept(Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		cond = Condition::None;
+
+		m_proto.resumeAccept(*this, cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \throw net::Error on failures
+	 */
+	inline void resumeAccept()
+	{
+		Condition dummy;
+
+		resumeAccept(dummy);
+	}
+
+	/**
+	 * Receive some data.
+	 *
+	 * \pre isOpen()
+	 * \param data the destination buffer
+	 * \param length the data length
+	 * \param cond the condition
+	 * \return the number of bytes received
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t recv(void *data, std::size_t length, Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		cond = Condition::None;
+
+		return m_proto.recv(*this, data, length, cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the destination buffer
+	 * \param length the data length
+	 * \return the number of bytes received
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t recv(void *data, std::size_t length)
+	{
+		Condition dummy;
+
+		return recv(data, length, dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param count number of bytes desired
+	 * \param cond the condition
+	 * \return the result string
+	 * \throw net::Error on failures
+	 */
+	std::string recv(std::size_t count, Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		std::string result;
+
+		result.resize(count);
+		auto n = recv(const_cast<char *>(result.data()), count, cond);
+		result.resize(n);
+
+		return result;
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param count number of bytes desired
+	 * \return the result string
+	 * \throw net::Error on failures
+	 */
+	inline std::string recv(std::size_t count)
+	{
+		Condition dummy;
+
+		return recv(count, dummy);
+	}
+
+	/**
+	 * Send some data.
+	 *
+	 * \pre isOpen()
+	 * \param data the data to send
+	 * \param length the length
+	 * \param cond the condition
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t send(const void *data, std::size_t length, Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		cond = Condition::None;
+
+		return m_proto.send(*this, data, length, cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data to send
+	 * \param length the length
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t send(const void *data, std::size_t length)
+	{
+		Condition dummy;
+
+		return send(data, length, dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data to send
+	 * \param cond the condition
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t send(const std::string &data, Condition &cond)
+	{
+		return send(data.c_str(), data.length(), cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data to send
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t send(const std::string &data)
+	{
+		Condition dummy;
+
+		return send(data.c_str(), data.length(), dummy);
+	}
+
+	/**
+	 * Send some data to the given client.
+	 *
+	 * \pre isOpen()
+	 * \param data the data
+	 * \param length the length
+	 * \param address the client address
+	 * \param addrlen the client address length
+	 * \param cond the condition
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t sendto(const void *data, std::size_t length, const sockaddr *address, socklen_t addrlen, Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		cond = Condition::None;
+
+		return m_proto.sendto(*this, data, length, address, addrlen, cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data
+	 * \param length the length
+	 * \param address the client address
+	 * \param addrlen the client address length
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t sendto(const void *data, std::size_t length, const sockaddr *address, socklen_t addrlen)
+	{
+		Condition dummy;
+
+		return send(data, length, address, addrlen, dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data
+	 * \param length the length
+	 * \param address the client address
+	 * \param cond the condition
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t sendto(const void *data, std::size_t length, const Address &address, Condition &cond)
+	{
+		return sendto(data, length, address.address(), address.length(), cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data
+	 * \param length the length
+	 * \param address the client address
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t sendto(const void *data, std::size_t length, const Address &address)
+	{
+		Condition dummy;
+
+		return sendto(data, length, address.address(), address.length(), dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data
+	 * \param cond the condition
+	 * \param address the client address
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t sendto(const std::string &data, const Address &address, Condition &cond)
+	{
+		return sendto(data.c_str(), data.length(), address.address(), address.length(), cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the data
+	 * \param address the client address
+	 * \return the number of bytes sent
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t sendto(const std::string &data, const Address &address)
+	{
+		Condition dummy;
+
+		return sendto(data.c_str(), data.length(), address.address(), address.length(), dummy);
+	}
+
+	/**
+	 * Receive some data from a client.
+	 *
+	 * \pre isOpen()
+	 * \param data the destination buffer
+	 * \param length the buffer length
+	 * \param address the client information
+	 * \param addrlen the client address initial length
+	 * \param cond the condition
+	 * \return the number of bytes received
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t recvfrom(void *data, std::size_t length, sockaddr *address, socklen_t *addrlen, Condition &cond)
+	{
+		assert(m_handle != Invalid);
+
+		cond = Condition::None;
+
+		return m_proto.recvfrom(*this, data, length, address, addrlen, cond);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the destination buffer
+	 * \param length the buffer length
+	 * \param address the client information
+	 * \param addrlen the client address initial length
+	 * \return the number of bytes received
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t recvfrom(void *data, std::size_t length, sockaddr *address, socklen_t *addrlen)
+	{
+		Condition dummy;
+
+		return recvfrom(data, length, address, addrlen, dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the destination buffer
+	 * \param length the buffer length
+	 * \param address the client information
+	 * \param cond the condition
+	 * \return the number of bytes received
+	 * \throw net::Error on failures
+	 */
+	std::size_t recvfrom(void *data, std::size_t length, Address &address, Condition &cond)
+	{
+		sockaddr_storage storage;
+		socklen_t addrlen = sizeof (sockaddr_storage);
+
+		auto n = recvfrom(data, length, reinterpret_cast<sockaddr *>(&storage), &addrlen, cond);
+
+		if (n != 0 && cond == Condition::None)
+			address = Address(reinterpret_cast<sockaddr *>(&storage), addrlen);
+
+		return n;
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the destination buffer
+	 * \param length the buffer length
+	 * \param address the client information
+	 * \return the number of bytes received
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t recvfrom(void *data, std::size_t length, Address &address)
+	{
+		Condition dummy;
+
+		return recvfrom(data, length, address, dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param data the destination buffer
+	 * \param length the buffer length
+	 * \return the number of bytes received
+	 * \throw net::Error on failures
+	 */
+	inline std::size_t recvfrom(void *data, std::size_t length)
+	{
+		Address da;
+		Condition dc;
+
+		return recvfrom(data, length, da, dc);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param count the number of bytes desired
+	 * \param address the client information
+	 * \param cond the condition
+	 * \return the result string
+	 * \throw net::Error on failures
+	 */
+	std::string recvfrom(std::size_t count, Address &address, Condition &cond)
+	{
+		std::string result;
+
+		result.resize(count);
+		auto n = recvfrom(const_cast<char *>(result.data()), count, address, cond);
+		result.resize(n);
+
+		return result;
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param count the number of bytes desired
+	 * \param address the client information
+	 * \return the result string
+	 * \throw net::Error on failures
+	 */
+	inline std::string recvfrom(std::size_t count, Address &address)
+	{
+		Condition dummy;
+
+		return recvfrom(count, address, dummy);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre isOpen()
+	 * \param count the number of bytes desired
+	 * \return the result string
+	 * \throw net::Error on failures
+	 */
+	inline std::string recvfrom(std::size_t count)
+	{
+		Address da;
+		Condition dc;
+
+		return recvfrom(count, da, dc);
+	}
+
+	/**
+	 * Close the socket.
+	 *
+	 * Automatically called from the destructor.
+	 */
+	void close()
+	{
+		if (m_handle != Invalid) {
+#if defined(_WIN32)
+			::closesocket(m_handle);
+#else
+			::close(m_handle);
+#endif
+			m_handle = Invalid;
+		}
+	}
+
+	/**
+	 * Assignment operator forbidden.
+	 *
+	 * \return *this
+	 */
+	Socket &operator=(const Socket &) = delete;
+
+	/**
+	 * Transfer ownership from other to this. The other socket is left
+	 * invalid and will not be closed.
+	 *
+	 * \param other the other socket
+	 * \return this
+	 */
+	Socket &operator=(Socket &&other) noexcept
+	{
+		m_handle = other.m_handle;
+		m_proto = std::move(other.m_proto);
+
+		other.m_handle = Invalid;
+
+		return *this;
+	}
+};
+
+/**
+ * Compare two sockets.
+ *
+ * \param s1 the first socket
+ * \param s2 the second socket
+ * \return true if they equals
+ */
+template <typename Address, typename Protocol>
+inline bool operator==(const Socket<Address, Protocol> &s1, const Socket<Address, Protocol> &s2)
+{
+	return s1.handle() == s2.handle();
+}
+
+/**
+ * Compare two sockets.
+ *
+ * \param s1 the first socket
+ * \param s2 the second socket
+ * \return true if they are different
+ */
+template <typename Address, typename Protocol>
+inline bool operator!=(const Socket<Address, Protocol> &s1, const Socket<Address, Protocol> &s2)
+{
+	return s1.handle() != s2.handle();
+}
+
+/**
+ * Compare two sockets.
+ *
+ * \param s1 the first socket
+ * \param s2 the second socket
+ * \return true if s1 < s2
+ */
+template <typename Address, typename Protocol>
+inline bool operator<(const Socket<Address, Protocol> &s1, const Socket<Address, Protocol> &s2)
+{
+	return s1.handle() < s2.handle();
+}
+
+/**
+ * Compare two sockets.
+ *
+ * \param s1 the first socket
+ * \param s2 the second socket
+ * \return true if s1 > s2
+ */
+template <typename Address, typename Protocol>
+inline bool operator>(const Socket<Address, Protocol> &s1, const Socket<Address, Protocol> &s2)
+{
+	return s1.handle() > s2.handle();
+}
+
+/**
+ * Compare two sockets.
+ *
+ * \param s1 the first socket
+ * \param s2 the second socket
+ * \return true if s1 <= s2
+ */
+template <typename Address, typename Protocol>
+inline bool operator<=(const Socket<Address, Protocol> &s1, const Socket<Address, Protocol> &s2)
+{
+	return s1.handle() <= s2.handle();
+}
+
+/**
+ * Compare two sockets.
+ *
+ * \param s1 the first socket
+ * \param s2 the second socket
+ * \return true if s1 >= s2
+ */
+template <typename Address, typename Protocol>
+inline bool operator>=(const Socket<Address, Protocol> &s1, const Socket<Address, Protocol> &s2)
+{
+	return s1.handle() >= s2.handle();
+}
+
+/**
+ * \brief Predefined protocols.
+ */
+namespace protocol {
+
+/**
+ * \brief Clear TCP implementation.
+ * \ingroup net-module-tcp
+ *
+ * This is the basic TCP protocol that implements recv, send, connect and accept as wrappers of the usual
+ * C functions.
+ */
+class Tcp {
+public:
+	/**
+	 * Socket type.
+	 *
+	 * \return SOCK_STREAM
+	 */
+	inline int type() const noexcept
+	{
+		return SOCK_STREAM;
+	}
+
+	/**
+	 * Do nothing.
+	 *
+	 * This function is just present for compatibility, it should never be called.
+	 */
+	template <typename Address>
+	inline void create(Socket<Address, Tcp> &) const noexcept
+	{
+	}
+
+	/**
+	 * Initiate connection.
+	 *
+	 * \param sc the socket
+	 * \param address the address
+	 * \param length the address length
+	 * \param cond the condition
+	 */
+	template <typename Address, typename Protocol>
+	void connect(Socket<Address, Protocol> &sc, const sockaddr *address, socklen_t length, Condition &cond)
+	{
+		if (::connect(sc.handle(), address, length) == Failure) {
+			/*
+			 * Determine if the error comes from a non-blocking connect that cannot be
+			 * accomplished yet.
+			 */
+#if defined(_WIN32)
+			int error = WSAGetLastError();
+
+			if (error == WSAEWOULDBLOCK)
+				cond = Condition::Writable;
+			else
+				throw Error(Error::System, "connect", error);
+#else
+			if (errno == EINPROGRESS)
+				cond = Condition::Writable;
+			else
+				throw Error(Error::System, "connect");
+#endif
+		}
+	}
+
+	/**
+	 * Resume the connection.
+	 *
+	 * Just check for SOL_SOCKET/SO_ERROR.
+	 *
+	 * User is responsible to wait before the socket is writable, otherwise behavior is undefined.
+	 *
+	 * \param sc the socket
+	 * \param cond the condition
+	 */
+	template <typename Address, typename Protocol>
+	void resumeConnect(Socket<Address, Protocol> &sc, Condition &cond)
+	{
+		int error = sc.template get<int>(SOL_SOCKET, SO_ERROR);
+
+#if defined(_WIN32)
+		if (error == WSAEWOULDBLOCK)
+			cond = Condition::Writable;
+		else if (error != 0)
+			throw Error(Error::System, "connect", error);
+#else
+		if (error == EINPROGRESS)
+			cond = Condition::Writable;
+		else if (error != 0)
+			throw Error(Error::System, "connect", error);
+#endif
+	}
+
+	/**
+	 * Accept a new client.
+	 *
+	 * If there are no pending connection, an invalid socket is returned, condition is left to Condition::None.
+	 *
+	 * \param sc the socket
+	 * \param address the address
+	 * \param length the length
+	 * \return the new socket
+	 */
+	template <typename Address, typename Protocol>
+	Socket<Address, Protocol> accept(Socket<Address, Protocol> &sc, sockaddr *address, socklen_t *length, Condition &)
+	{
+		Handle handle = ::accept(sc.handle(), address, length);
+
+		if (handle == Invalid)
+			return Socket<Address, Protocol>();
+
+		return Socket<Address, Protocol>(handle);
+	}
+
+	/**
+	 * Resume accept process.
+	 *
+	 * No-op for TCP.
+	 */
+	template <typename Address, typename Protocol>
+	inline void resumeAccept(Socket<Address, Protocol> &, Condition &) const noexcept
+	{
+	}
+
+	/**
+	 * Receive some data.
+	 *
+	 * \param sc the socket
+	 * \param data the destination buffer
+	 * \param length the buffer length
+	 * \param cond the condition
+	 * \return the number of byte received
+	 */
+	template <typename Address>
+	std::size_t recv(Socket<Address, Tcp> &sc, void *data, std::size_t length, Condition &cond)
+	{
+		int max = length > INT_MAX ? INT_MAX : static_cast<int>(length);
+		int nbread = ::recv(sc.handle(), (Arg)data, max, 0);
+
+		if (nbread == Failure) {
+#if defined(_WIN32)
+			int error = WSAGetLastError();
+
+			if (error == WSAEWOULDBLOCK) {
+				nbread = 0;
+				cond = Condition::Readable;
+			} else
+				throw Error(Error::System, "recv", error);
+#else
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				nbread = 0;
+				cond = Condition::Readable;
+			} else
+				throw Error(Error::System, "recv");
+#endif
+		}
+
+		return static_cast<std::size_t>(nbread);
+	}
+
+	/**
+	 * Send some data.
+	 *
+	 * \param sc the socket
+	 * \param data the data to send
+	 * \param length the length
+	 * \param cond the condition
+	 * \return the number of bytes sent
+	 */
+	template <typename Address>
+	std::size_t send(Socket<Address, Tcp> &sc, const void *data, std::size_t length, Condition &cond)
+	{
+		int max = length > INT_MAX ? INT_MAX : static_cast<int>(length);
+		int nbsent = ::send(sc.handle(), (ConstArg)data, max, 0);
+
+		if (nbsent == Failure) {
+#if defined(_WIN32)
+			int error = WSAGetLastError();
+
+			if (error == WSAEWOULDBLOCK) {
+				nbsent = 0;
+				cond = Condition::Writable;
+			} else
+				throw Error(Error::System, "send", error);
+#else
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				nbsent = 0;
+				cond = Condition::Writable;
+			} else
+				throw Error(Error::System, "send");
+#endif
+		}
+
+		return static_cast<unsigned>(nbsent);
+	}
+};
+
+/**
+ * \brief Clear UDP type.
+ *
+ * This class is the basic implementation of UDP sockets.
+ */
+class Udp {
+public:
+	/**
+	 * Socket type.
+	 *
+	 * \return SOCK_DGRAM
+	 */
+	inline int type() const noexcept
+	{
+		return SOCK_DGRAM;
+	}
+
+	/**
+	 * Do nothing.
+	 */
+	template <typename Address, typename Protocol>
+	inline void create(Socket<Address, Protocol> &) noexcept
+	{
+	}
+
+	/**
+	 * Receive some data.
+	 *
+	 * \param sc the socket
+	 * \param data the data
+	 * \param length the length
+	 * \param address the source address
+	 * \param addrlen the source address in/out length
+	 * \param cond the condition
+	 * \return the number of bytes received
+	 */
+	template <typename Address, typename Protocol>
+	std::size_t recvfrom(Socket<Address, Protocol> &sc, void *data, std::size_t length, sockaddr *address, socklen_t *addrlen, Condition &cond)
+	{
+		int max = length > INT_MAX ? INT_MAX : static_cast<int>(length);
+		int nbread;
+
+		nbread = ::recvfrom(sc.handle(), (Arg)data, max, 0, address, addrlen);
+
+		if (nbread == Failure) {
+#if defined(_WIN32)
+			int error = WSAGetLastError();
+
+			if (error == WSAEWOULDBLOCK) {
+				nbread = 0;
+				cond = Condition::Writable;
+			} else
+				throw Error(Error::System, "recvfrom");
+#else
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				nbread = 0;
+				cond = Condition::Writable;
+			} else
+				throw Error(Error::System, "recvfrom");
+#endif
+		}
+
+		return static_cast<unsigned>(nbread);
+	}
+
+	/**
+	 * Send some data.
+	 *
+	 * \param sc the socket
+	 * \param data the data to send
+	 * \param length the data length
+	 * \param address the destination address
+	 * \param addrlen the destination address length
+	 * \param cond the condition
+	 * \return the number of bytes sent
+	 */
+	template <typename Address, typename Protocol>
+	std::size_t sendto(Socket<Address, Protocol> &sc, const void *data, std::size_t length, const sockaddr *address, socklen_t addrlen, Condition &cond)
+	{
+		int max = length > INT_MAX ? INT_MAX : static_cast<int>(length);
+		int nbsent;
+
+		nbsent = ::sendto(sc.handle(), (ConstArg)data, max, 0, address, addrlen);
+		if (nbsent == Failure) {
+#if defined(_WIN32)
+			int error = WSAGetLastError();
+
+			if (error == WSAEWOULDBLOCK) {
+				nbsent = 0;
+				cond = Condition::Writable;
+			} else
+				throw Error(Error::System, "sendto", error);
+#else
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				nbsent = 0;
+				cond = Condition::Writable;
+			} else
+				throw Error(Error::System, "sendto");
+#endif
+		}
+
+		return static_cast<unsigned>(nbsent);
+	}
+};
+
+#if !defined(NET_NO_SSL)
+
+/**
+ * \brief Experimental TLS support.
+ * \ingroup net-module-tls
+ * \warning This class is highly experimental.
+ */
+class Tls : private Tcp {
+private:
+	using Context = std::shared_ptr<SSL_CTX>;
+	using Ssl = std::unique_ptr<SSL, void (*)(SSL *)>;
+
+	// OpenSSL objects.
+	Context m_context;
+	Ssl m_ssl{nullptr, nullptr};
+
+	// Status.
+	bool m_tcpconnected{false};
+
+	/*
+	 * User definable parameters.
+	 */
+	ssl::Method m_method{ssl::Tlsv1};
+	std::string m_key;
+	std::string m_certificate;
+	bool m_verify{false};
+
+	// Construct with a context and ssl, for Tls::accept.
+	Tls(Context context, Ssl ssl)
+		: m_context(std::move(context))
+		, m_ssl(std::move(ssl))
+	{
+	}
+
+	inline std::string error()
+	{
+		BIO *bio = BIO_new(BIO_s_mem());
+		char *buf = nullptr;
+
+		ERR_print_errors(bio);
+
+		std::size_t length = BIO_get_mem_data (bio, &buf);
+		std::string result(buf, length);
+
+		BIO_free(bio);
+
+		return result;
+	}
+
+	template <typename Function>
+	void wrap(const std::string &func, Condition &cond, Function &&function)
+	{
+		auto ret = function();
+
+		if (ret <= 0) {
+			int no = SSL_get_error(m_ssl.get(), ret);
+
+			switch (no) {
+			case SSL_ERROR_WANT_READ:
+				cond = Condition::Readable;
+				break;
+			case SSL_ERROR_WANT_WRITE:
+				cond = Condition::Writable;
+				break;
+			default:
+				throw Error(Error::System, func, error());
+			}
+		}
+	}
+
+	template <typename Address, typename Protocol>
+	void doConnect(Socket<Address, Protocol> &, Condition &cond)
+	{
+		wrap("connect", cond, [&] () -> int {
+			return SSL_connect(m_ssl.get());
+		});
+	}
+
+	template <typename Address, typename Protocol>
+	void doAccept(Socket<Address, Protocol> &, Condition &cond)
+	{
+		wrap("accept", cond, [&] () -> int {
+			return SSL_accept(m_ssl.get());
+		});
+	}
+
+public:
+	/**
+	 * \copydoc Tcp::type
+	 */
+	inline int type() const noexcept
+	{
+		return SOCK_STREAM;
+	}
+
+	/**
+	 * Empty TLS constructor.
+	 */
+	inline Tls()
+	{
+#if !defined(NET_NO_SSL_AUTO_INIT)
+		ssl::init();
+#endif
+	}
+
+	/**
+	 * Set the method.
+	 *
+	 * \param method the method
+	 * \pre the socket must not be already created
+	 */
+	inline void setMethod(ssl::Method method) noexcept
+	{
+		assert(!m_context);
+		assert(!m_ssl);
+
+		m_method = method;
+	}
+
+	/**
+	 * Use the specified private key file.
+	 *
+	 * \param file the path to the private key
+	 */
+	inline void setPrivateKey(std::string file) noexcept
+	{
+		m_key = std::move(file);
+	}
+
+	/**
+	 * Use the specified certificate file.
+	 *
+	 * \param file the path to the file
+	 */
+	inline void setCertificate(std::string file) noexcept
+	{
+		m_certificate = std::move(file);
+	}
+
+	/**
+	 * Set to true if we must verify the certificate and private key.
+	 *
+	 * \param verify the mode
+	 */
+	inline void setVerify(bool verify = true) noexcept
+	{
+		m_verify = verify;
+	}
+
+	/**
+	 * Initialize the SSL objects after have created.
+	 *
+	 * \param sc the socket
+	 * \throw net::Error on errors
+	 */
+	template <typename Address>
+	void create(Socket<Address, Tls> &sc)
+	{
+		auto method = (m_method == ssl::Tlsv1) ? TLSv1_method() : SSLv23_method();
+
+		m_context = Context(SSL_CTX_new(method), SSL_CTX_free);
+		m_ssl = Ssl(SSL_new(m_context.get()), SSL_free);
+
+		SSL_set_fd(m_ssl.get(), static_cast<int>(sc.handle()));
+
+		/*
+		 * Load certificates, the wrap function requires a condition so just add a dummy value.
+		 */
+		Condition dummy;
+
+		if (m_certificate.size() > 0)
+			wrap("SSL_CTX_use_certificate_file", dummy, [&] () -> int {
+				return SSL_CTX_use_certificate_file(m_context.get(), m_certificate.c_str(), SSL_FILETYPE_PEM);
+			});
+		if (m_key.size() > 0)
+			wrap("SSL_CTX_use_PrivateKey_file", dummy, [&] () -> int {
+				return SSL_CTX_use_PrivateKey_file(m_context.get(), m_key.c_str(), SSL_FILETYPE_PEM);
+			});
+		if (m_verify && !SSL_CTX_check_private_key(m_context.get()))
+			throw Error(Error::System, "(openssl)", "unable to verify key");
+	}
+
+	/**
+	 * Initiate connection.
+	 *
+	 * \param sc the socket
+	 * \param address the address
+	 * \param length the address length
+	 * \param cond the condition
+	 */
+	template <typename Address, typename Protocol>
+	void connect(Socket<Address, Protocol> &sc, const sockaddr *address, socklen_t length, Condition &cond)
+	{
+		// 1. Connect using raw TCP.
+		Tcp::connect(sc, address, length, cond);
+
+		// 2. If the connection is complete (e.g. non-blocking), try handshake.
+		if (cond == Condition::None) {
+			m_tcpconnected = true;
+			doConnect(sc, cond);
+		}
+	}
+
+	/**
+	 * Resume the connection.
+	 *
+	 * \param sc the socket
+	 * \param cond the condition to wait
+	 */
+	template <typename Address, typename Protocol>
+	void resumeConnect(Socket<Address, Protocol> &sc, Condition &cond)
+	{
+		// 1. Be sure to complete standard connect before.
+		if (!m_tcpconnected) {
+			Tcp::resumeConnect(sc, cond);
+			m_tcpconnected = (cond == Condition::None);
+		}
+
+		// 2. Do SSL connect.
+		if (m_tcpconnected)
+			doConnect(sc, cond);
+	}
+
+	/**
+	 * Accept a new client.
+	 *
+	 * If there are no pending connection, an invalid socket is returned, condition is left to Condition::None.
+	 *
+	 * \param sc the socket
+	 * \param address the address
+	 * \param length the length
+	 * \param cond the condition to wait
+	 * \return the new socket
+	 */
+	template <typename Address>
+	Socket<Address, Tls> accept(Socket<Address, Tls> &sc, sockaddr *address, socklen_t *length, Condition &cond)
+	{
+		// 1. TCP returns empty client if no pending connection is available.
+		auto client = Tcp::accept(sc, address, length, cond);
+
+		// 2. If a client is available, try initial accept.
+		if (client.isOpen()) {
+			Tls &proto = client.protocol();
+
+			// 2.1. Share the context.
+			proto.m_context = m_context;
+
+			// 2.2. Create new SSL instance.
+			proto.m_ssl = Ssl(SSL_new(m_context.get()), SSL_free);
+
+			SSL_set_fd(proto.m_ssl.get(), static_cast<int>(client.handle()));
+
+			// 2.3. Try accept process on the **new** client.
+			proto.doAccept(client, cond);
+		}
+
+		return client;
+	}
+
+	/**
+	 * Resume accept process.
+	 *
+	 * \param sc the socket
+	 * \param cond the condition to wait
+	 * \throw net::Error on failures
+	 */
+	template <typename Address, typename Protocol>
+	inline void resumeAccept(Socket<Address, Protocol> &sc, Condition &cond)
+	{
+		doAccept(sc, cond);
+	}
+
+	/**
+	 * Receive some data.
+	 *
+	 * \param data the destination buffer
+	 * \param length the buffer length
+	 * \param cond the condition
+	 * \return the number of bytes received
+	 */
+	template <typename Address>
+	std::size_t recv(Socket<Address, Tls> &, void *data, std::size_t length, Condition &cond)
+	{
+		int max = length > INT_MAX ? INT_MAX : static_cast<int>(length);
+		int nbread = 0;
+
+		wrap("recv", cond, [&] () -> int {
+			return (nbread = SSL_read(m_ssl.get(), data, max));
+		});
+
+		return static_cast<std::size_t>(nbread < 0 ? 0 : nbread);
+	}
+
+	/**
+	 * Send some data.
+	 *
+	 * \param data the data to send
+	 * \param length the length
+	 * \param cond the condition
+	 * \return the number of bytes sent
+	 */
+	template <typename Address>
+	std::size_t send(Socket<Address, Tls> &, const void *data, std::size_t length, Condition &cond)
+	{
+		int max = length > INT_MAX ? INT_MAX : static_cast<int>(length);
+		int nbsent = 0;
+
+		wrap("send", cond, [&] () -> int {
+			return (nbsent = SSL_write(m_ssl.get(), data, max));
+		});
+
+		return static_cast<std::size_t>(nbsent < 0 ? 0 : nbsent);
+	}
+};
+
+#endif // !NET_NO_SSL
+
+} // !protocol
+
+/**
+ * \brief Predefined addresses.
+ */
+namespace address {
+
+/**
+ * \brief Generic address.
+ * \ingroup net-module-addresses
+ *
+ * This address can store anything that fits into a sockaddr_storage.
+ */
+class Generic {
+private:
+	sockaddr_storage m_address;
+	socklen_t m_length{0};
+
+public:
+	/**
+	 * Construct a null address.
+	 */
+	inline Generic() noexcept
+	{
+		std::memset(&m_address, 0, sizeof (sockaddr_storage));
+	}
+
+	/**
+	 * Construct an address.
+	 *
+	 * \pre address is not null
+	 * \pre length <= sizeof (sockaddr_storage)
+	 * \param address the address to copy
+	 * \param length the address length
+	 */
+	inline Generic(const sockaddr *address, socklen_t length) noexcept
+		: m_length(length)
+	{
+		assert(address);
+		assert(length <= sizeof (sockaddr_storage));
+
+		std::memset(&m_address, 0, sizeof (sockaddr_storage));
+		std::memcpy(&m_address, address, length);
+	}
+
+	/**
+	 * Get the address family.
+	 *
+	 * \return the address family
+	 */
+	inline int domain() const noexcept
+	{
+		return m_address.ss_family;
+	}
+
+	/**
+	 * Get the underlying address.
+	 *
+	 * \return the address
+	 */
+	inline sockaddr *address() noexcept
+	{
+		return reinterpret_cast<sockaddr *>(&m_address);
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \return the address
+	 */
+	inline const sockaddr *address() const noexcept
+	{
+		return reinterpret_cast<const sockaddr *>(&m_address);
+	}
+
+	/**
+	 * Get the underlying address length.
+	 *
+	 * \return the length
+	 */
+	inline socklen_t length() const noexcept
+	{
+		return m_length;
+	}
+};
+
+/**
+ * Compare two generic addresses.
+ *
+ * \param a1 the first address
+ * \param a2 the second address
+ * \return true if they equal
+ */
+inline bool operator==(const Generic &a1, const Generic &a2) noexcept
+{
+	return a1.length() == a2.length() && std::memcmp(a1.address(), a2.address(), a1.length()) == 0;
+}
+
+/**
+ * Compare two generic addresses.
+ *
+ * \param a1 the first address
+ * \param a2 the second address
+ * \return false if they equal
+ */
+inline bool operator!=(const Generic &a1, const Generic &a2) noexcept
+{
+	return !(a1 == a2);
+}
+
+/**
+ * \brief Generic IP address.
+ * \ingroup net-module-addresses
+ *
+ * You can use this address instead of Ipv4 or Ipv6 if you don't know which address to use at runtime. However,
+ * when creating your socket, you will need to define the correct domain.
+ */
+class Ip {
+private:
+	union {
+		sockaddr_in6 m_sin6;
+		sockaddr_in m_sin;
+	};
+
+	int m_domain;
+
+public:
+	/**
+	 * Create IP address, defaults to IPv4.
+	 *
+	 * \pre domain must be AF_INET or AF_INET6
+	 * \param domain the domain
+	 */
+	inline Ip(int domain = AF_INET) noexcept
+		: m_domain(domain)
+	{
+		assert(domain == AF_INET || domain == AF_INET6);
+
+		std::memset(&m_sin, 0, sizeof (sockaddr_in));
+	}
+
+	/**
+	 * Create an IP address on the specific ip address.
+	 *
+	 * \pre domain must be AF_INET or AF_INET6
+	 * \param ip the address or "*" for any
+	 * \param port the port
+	 * \param domain the domain
+	 * \warning If NET_HAVE_INET_PTON is undefined, host can not be other than "*"
+	 * \throw net::Error on failures or if inet_pton is unavailable
+	 */
+	inline Ip(const std::string &ip, std::uint16_t port, int domain)
+		: Ip(domain)
+	{
+		if (m_domain == AF_INET)
+			make(ip, port, m_sin);
+		else
+			make(ip, port, m_sin6);
+	}
+
+	/**
+	 * Create the IP address from the storage.
+	 *
+	 * \pre the storage domain must be AF_INET or AF_INET6
+	 * \param ss the the storage
+	 * \param length the storage length
+	 */
+	inline Ip(const sockaddr *ss, socklen_t length) noexcept
+		: Ip(ss->sa_family)
+	{
+		assert(ss->sa_family == AF_INET || ss->sa_family == AF_INET6);
+
+		if (ss->sa_family == AF_INET)
+			std::memcpy(&m_sin, ss, length);
+		else
+			std::memcpy(&m_sin6, ss, length);
+	}
+
+	/**
+	 * Get the domain.
+	 *
+	 * \return AF_INET or AF_INET6
+	 */
+	inline int domain() const noexcept
+	{
+		return m_domain;
+	}
+
+	/**
+	 * Get the underlying address, may be a sockaddr_in or sockaddr_in6.
+	 *
+	 * \return the address
+	 */
+	inline const sockaddr *address() const noexcept
+	{
+		return m_domain == AF_INET ? reinterpret_cast<const sockaddr *>(&m_sin) : reinterpret_cast<const sockaddr *>(&m_sin6);
+	}
+
+	/**
+	 * Get the address length.
+	 *
+	 * \return the address length
+	 */
+	inline socklen_t length() const noexcept
+	{
+		return m_domain == AF_INET ? sizeof (sockaddr_in) : sizeof (sockaddr_in6);
+	}
+
+	/**
+	 * Retrieve the port.
+	 *
+	 * \return the port
+	 */
+	inline std::uint16_t port() const noexcept
+	{
+		return m_domain == AF_INET ? ntohs(m_sin.sin_port) : ntohs(m_sin6.sin6_port);
+	}
+
+	/**
+	 * Get the ip address.
+	 *
+	 * \return the ip address
+	 * \throw net::Error on errors or if inet_ntop is unavailable
+	 */
+	inline std::string ip() const
+	{
+		return m_domain == AF_INET ? ip(m_sin) : ip(m_sin6);
+	}
+
+	/**
+	 * Prepare the sockaddr_in structure with the given ip.
+	 *
+	 * \param ip the ip address
+	 * \param port the port
+	 * \param sin the Ipv4 address
+	 * \throw net::Error if inet_pton is unavailable
+	 */
+	static void make(const std::string &ip, std::uint16_t port, sockaddr_in &sin)
+	{
+#if !defined(NET_NO_AUTO_INIT)
+		net::init();
+#endif
+
+		sin.sin_family = AF_INET;
+		sin.sin_port = htons(port);
+
+		if (ip == "*")
+			sin.sin_addr.s_addr = INADDR_ANY;
+#if defined(NET_HAVE_INET_PTON)
+		else if (inet_pton(AF_INET, ip.c_str(), &sin.sin_addr) <= 0)
+			throw Error(Error::System, "inet_pton");
+#else
+		else
+			throw Error(Error::System, "inet_pton", std::strerror(ENOSYS));
+#endif
+	}
+
+	/**
+	 * Prepare the sockaddr_in structure with the given ip.
+	 *
+	 * \param ip the ip address
+	 * \param port the port
+	 * \param sin6 the Ipv6 address
+	 * \throw net::Error if inet_pton is unavailable
+	 */
+	static void make(const std::string &ip, std::uint16_t port, sockaddr_in6 &sin6)
+	{
+#if !defined(NET_NO_AUTO_INIT)
+		net::init();
+#endif
+
+		sin6.sin6_family = AF_INET6;
+		sin6.sin6_port = htons(port);
+
+		if (ip == "*")
+			sin6.sin6_addr = in6addr_any;
+#if defined(NET_HAVE_INET_PTON)
+		else if (inet_pton(AF_INET6, ip.c_str(), &sin6.sin6_addr) <= 0)
+			throw Error(Error::System, "inet_pton");
+#else
+		else
+			throw Error(Error::System, "inet_pton", std::strerror(ENOSYS));
+#endif
+	}
+
+	/**
+	 * Get the underlying ip from the given address.
+	 *
+	 * \param sin the Ipv4 address
+	 * \return the ip address
+	 * \throw net::Error if inet_ntop is unavailable
+	 */
+	static std::string ip(const sockaddr_in &sin)
+	{
+#if !defined(NET_NO_AUTO_INIT)
+		net::init();
+#endif
+
+#if !defined(NET_HAVE_INET_NTOP)
+		(void)sin;
+
+		throw Error(Error::System, "inet_ntop", std::strerror(ENOSYS));
+#else
+		char result[INET_ADDRSTRLEN + 1];
+
+		std::memset(result, 0, sizeof (result));
+
+		if (!inet_ntop(AF_INET, const_cast<in_addr *>(&sin.sin_addr), result, sizeof (result)))
+			throw Error(Error::System, "inet_ntop");
+
+		return result;
+#endif
+	}
+
+	/**
+	 * Get the underlying ip from the given address.
+	 *
+	 * \param sin6 the Ipv6 address
+	 * \return the ip address
+	 * \throw net::Error if inet_ntop is unavailable
+	 */
+	static std::string ip(const sockaddr_in6 &sin6)
+	{
+#if !defined(NET_NO_AUTO_INIT)
+		net::init();
+#endif
+
+#if !defined(NET_HAVE_INET_NTOP)
+		(void)sin6;
+
+		throw Error(Error::System, "inet_ntop", std::strerror(ENOSYS));
+#else
+		char result[INET6_ADDRSTRLEN];
+
+		std::memset(result, 0, sizeof (result));
+
+		if (!inet_ntop(AF_INET6, const_cast<in6_addr *>(&sin6.sin6_addr), result, sizeof (result)))
+			throw Error(Error::System, "inet_ntop");
+
+		return result;
+#endif
+	}
+
+	/**
+	 * Resolve an hostname.
+	 *
+	 * This function wraps getaddrinfo and returns the first result.
+	 *
+	 * \param host the hostname
+	 * \param service the service name (port or name)
+	 * \param domain the domain (e.g. AF_INET)
+	 * \param type the socket type (e.g. SOCK_STREAM)
+	 * \return the resolved address
+	 * \throw net::Error on failures
+	 */
+	static Ip resolve(const std::string &host, const std::string &service, int domain = AF_INET, int type = SOCK_STREAM)
+	{
+		assert(domain == AF_INET || domain == AF_INET6);
+#if !defined(NET_NO_AUTO_INIT)
+		net::init();
+#endif
+
+		struct addrinfo hints, *res;
+
+		std::memset(&hints, 0, sizeof (struct addrinfo));
+		hints.ai_family = domain;
+		hints.ai_socktype = type;
+
+		int e = getaddrinfo(host.c_str(), service.c_str(), &hints, &res);
+
+		if (e != 0)
+			throw Error(Error::System, "getaddrinfo", gai_strerror(e));
+
+		Ip ip(res->ai_addr, res->ai_addrlen);
+
+		freeaddrinfo(res);
+
+		return ip;
+	}
+};
+
+/**
+ * \brief Ipv4 only address.
+ * \ingroup net-module-addresses
+ */
+class Ipv4 {
+private:
+	sockaddr_in m_sin;
+
+public:
+	/**
+	 * Create an Ipv4 address.
+	 */
+	inline Ipv4() noexcept
+	{
+		std::memset(&m_sin, 0, sizeof (sockaddr_in));
+	}
+
+	/**
+	 * Create an Ipv4 address on the specific ip address.
+	 *
+	 * \param ip the address or "*" for any
+	 * \param port the port
+	 * \warning If NET_HAVE_INET_PTON is undefined, host can not be other than "*"
+	 * \throw net::Error on failures or if inet_pton is unavailable
+	 */
+	inline Ipv4(const std::string &ip, std::uint16_t port)
+		: Ipv4()
+	{
+		Ip::make(ip, port, m_sin);
+	}
+
+	/**
+	 * Create the IP address from the storage.
+	 *
+	 * \pre the storage domain must be AF_INET
+	 * \param ss the the storage
+	 * \param length the storage length
+	 */
+	inline Ipv4(const sockaddr *ss, socklen_t length) noexcept
+	{
+		assert(ss->sa_family == AF_INET);
+
+		std::memcpy(&m_sin, ss, length);
+	}
+
+	/**
+	 * Get the domain.
+	 *
+	 * \return AF_INET
+	 */
+	inline int domain() const noexcept
+	{
+		return AF_INET;
+	}
+
+	/**
+	 * Get the underlying address.
+	 *
+	 * \return the address
+	 */
+	inline const sockaddr *address() const noexcept
+	{
+		return reinterpret_cast<const sockaddr *>(&m_sin);
+	}
+
+	/**
+	 * Get the address length.
+	 *
+	 * \return the size of sockaddr_in
+	 */
+	inline socklen_t length() const noexcept
+	{
+		return sizeof (sockaddr_in);
+	}
+
+	/**
+	 * Get the port.
+	 *
+	 * \return the port
+	 */
+	inline std::uint16_t port() const noexcept
+	{
+		return ntohs(m_sin.sin_port);
+	}
+
+	/**
+	 * Get the ip address.
+	 *
+	 * \return the ip address
+	 * \throw net::Error on errors or if inet_ntop is unavailable
+	 */
+	inline std::string ip() const
+	{
+		return Ip::ip(m_sin);
+	}
+
+	/**
+	 * Same as Ip::resolve with AF_INET as domain.
+	 *
+	 * \param host the hostname
+	 * \param service the service name (port or name)
+	 * \param type the socket type (e.g. SOCK_STREAM)
+	 * \return the resolved address
+	 * \throw net::Error on failures
+	 */
+	static Ipv4 resolve(const std::string &host, const std::string &service, int type = SOCK_STREAM)
+	{
+		Ip result = Ip::resolve(host, service, AF_INET, type);
+
+		return Ipv4(result.address(), result.length());
+	}
+};
+
+/**
+ * \brief Ipv4 only address.
+ * \ingroup net-module-addresses
+ */
+class Ipv6 {
+private:
+	sockaddr_in6 m_sin6;
+
+public:
+	/**
+	 * Create an Ipv6 address.
+	 */
+	inline Ipv6() noexcept
+	{
+		std::memset(&m_sin6, 0, sizeof (sockaddr_in6));
+	}
+
+	/**
+	 * Create an Ipv6 address on the specific ip address.
+	 *
+	 * \param ip the address or "*" for any
+	 * \param port the port
+	 * \warning If NET_HAVE_INET_PTON is undefined, host can not be other than "*"
+	 * \throw net::Error on failures or if inet_pton is unavailable
+	 */
+	inline Ipv6(const std::string &ip, std::uint16_t port)
+		: Ipv6()
+	{
+		Ip::make(ip, port, m_sin6);
+	}
+
+	/**
+	 * Create the IP address from the storage.
+	 *
+	 * \pre the storage domain must be AF_INET6
+	 * \param ss the the storage
+	 * \param length the storage length
+	 */
+	inline Ipv6(const sockaddr *ss, socklen_t length) noexcept
+	{
+		assert(ss->sa_family == AF_INET6);
+
+		std::memcpy(&m_sin6, ss, length);
+	}
+
+	/**
+	 * Get the domain.
+	 *
+	 * \return AF_INET6
+	 */
+	inline int domain() const noexcept
+	{
+		return AF_INET6;
+	}
+
+	/**
+	 * Get the underlying address.
+	 *
+	 * \return the address
+	 */
+	inline const sockaddr *address() const noexcept
+	{
+		return reinterpret_cast<const sockaddr *>(&m_sin6);
+	}
+
+	/**
+	 * Get the address length.
+	 *
+	 * \return the size of sockaddr_in
+	 */
+	inline socklen_t length() const noexcept
+	{
+		return sizeof (sockaddr_in6);
+	}
+
+	/**
+	 * Get the port.
+	 *
+	 * \return the port
+	 */
+	inline std::uint16_t port() const noexcept
+	{
+		return ntohs(m_sin6.sin6_port);
+	}
+
+	/**
+	 * Get the ip address.
+	 *
+	 * \return the ip address
+	 * \throw net::Error on errors or if inet_ntop is unavailable
+	 */
+	inline std::string ip() const
+	{
+		return Ip::ip(m_sin6);
+	}
+
+	/**
+	 * Same as Ip::resolve with AF_INET6 as domain.
+	 *
+	 * \param host the hostname
+	 * \param service the service name (port or name)
+	 * \param type the socket type (e.g. SOCK_STREAM)
+	 * \return the resolved address
+	 * \throw net::Error on failures
+	 */
+	static Ipv6 resolve(const std::string &host, const std::string &service, int type = SOCK_STREAM)
+	{
+		Ip result = Ip::resolve(host, service, AF_INET6, type);
+
+		return Ipv6(result.address(), result.length());
+	}
+};
+
+#if !defined(_WIN32)
+
+/**
+ * \brief unix family sockets
+ * \ingroup net-module-addresses
+ *
+ * Create an address to a specific path. Only available on Unix.
+ */
+class Local {
+private:
+	sockaddr_un m_sun;
+	std::string m_path;
+
+public:
+	/**
+	 * Get the domain AF_LOCAL.
+	 *
+	 * \return AF_LOCAL
+	 */
+	inline int domain() const noexcept
+	{
+		return AF_LOCAL;
+	}
+
+	/**
+	 * Default constructor.
+	 */
+	inline Local() noexcept
+	{
+		std::memset(&m_sun, 0, sizeof (sockaddr_un));
+	}
+
+	/**
+	 * Construct an address to a path.
+	 *
+	 * \param path the path
+	 * \param rm remove the file before (default: false)
+	 */
+	Local(std::string path, bool rm = false) noexcept
+		: m_path(std::move(path))
+	{
+		// Silently remove the file even if it fails.
+		if (rm)
+			::remove(m_path.c_str());
+
+		// Copy the path.
+		std::memset(m_sun.sun_path, 0, sizeof (m_sun.sun_path));
+		std::strncpy(m_sun.sun_path, m_path.c_str(), sizeof (m_sun.sun_path) - 1);
+
+		// Set the parameters.
+		m_sun.sun_family = AF_LOCAL;
+	}
+
+	/**
+	 * Construct an unix address from a storage address.
+	 *
+	 * \pre storage's domain must be AF_LOCAL
+	 * \param ss the storage
+	 * \param length the length
+	 */
+	Local(const sockaddr *ss, socklen_t length) noexcept
+	{
+		assert(ss->sa_family == AF_LOCAL);
+
+		std::memcpy(&m_sun, ss, length);
+		m_path = reinterpret_cast<const sockaddr_un &>(m_sun).sun_path;
+	}
+
+	/**
+	 * Get the sockaddr_un.
+	 *
+	 * \return the address
+	 */
+	inline const sockaddr *address() const noexcept
+	{
+		return reinterpret_cast<const sockaddr *>(&m_sun);
+	}
+
+	/**
+	 * Get the address length.
+	 *
+	 * \return the length
+	 */
+	inline socklen_t length() const noexcept
+	{
+#if defined(NET_HAVE_SUN_LEN)
+		return SUN_LEN(&m_sun);
+#else
+		return sizeof (m_sun);
+#endif
+	}
+};
+
+#endif // !_WIN32
+
+/**
+ * \brief Address iterator.
+ * \ingroup net-module-addresses
+ * \see resolve
+ *
+ * This iterator can be used to try to connect to an host.
+ *
+ * When you use net::resolve with unspecified domain or socket type, the function may retrieve several different addresses that you can
+ * iterate over to try to connect to.
+ *
+ * Example:
+ *
+ * ````cpp
+ * net::SocketTcpIp sc;
+ * net::AddressIterator end, it = net::resolve("hostname.test", "80");
+ *
+ * while (!connected_condition && it != end)
+ *   sc.connect(it->address(), it->length());
+ * ````
+ *
+ * When an iterator equals to a default constructed iterator, it is considered not dereferenceable.
+ */
+class AddressIterator : public std::iterator<std::forward_iterator_tag, Generic> {
+private:
+	std::vector<Generic> m_addresses;
+	std::size_t m_index{0};
+
+public:
+	/**
+	 * Construct a null iterator.
+	 *
+	 * The default constructed iterator is not dereferenceable.
+	 */
+	inline AddressIterator() noexcept = default;
+
+	/**
+	 * Construct an address iterator with a set of addresses.
+	 *
+	 * \pre index < m_addresses.size()
+	 * \param addresses the addresses
+	 * \param index the first index
+	 */
+	inline AddressIterator(std::vector<Generic> addresses, std::size_t index = 0) noexcept
+		: m_addresses(std::move(addresses))
+		, m_index(index)
+	{
+		assert(index < m_addresses.size());
+	}
+
+	/**
+	 * Get the generic address.
+	 *
+	 * \pre this is dereferenceable
+	 * \return the generic address
+	 */
+	inline const Generic &operator*() const noexcept
+	{
+		assert(m_index <= m_addresses.size());
+
+		return m_addresses[m_index];
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre this is dereferenceable
+	 * \return the generic address
+	 */
+	inline Generic &operator*() noexcept
+	{
+		assert(m_index <= m_addresses.size());
+
+		return m_addresses[m_index];
+	}
+
+	/**
+	 * Get the generic address.
+	 *
+	 * \pre this is dereferenceable
+	 * \return the generic address
+	 */
+	inline const Generic *operator->() const noexcept
+	{
+		assert(m_index <= m_addresses.size());
+
+		return &m_addresses[m_index];
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \pre this is dereferenceable
+	 * \return the generic address
+	 */
+	inline Generic *operator->() noexcept
+	{
+		assert(m_index <= m_addresses.size());
+
+		return &m_addresses[m_index];
+	}
+
+	/**
+	 * Pre-increment the iterator.
+	 *
+	 * \return this
+	 */
+	inline AddressIterator &operator++(int) noexcept
+	{
+		if (m_index + 1 >= m_addresses.size()) {
+			m_addresses.clear();
+			m_index = 0;
+		} else
+			m_index ++;
+
+		return *this;
+	}
+
+	/**
+	 * Post-increment the iterator.
+	 *
+	 * \return copy of this
+	 */
+	inline AddressIterator operator++() noexcept
+	{
+		AddressIterator save = *this;
+
+		if (m_index + 1 >= m_addresses.size()) {
+			m_addresses.clear();
+			m_index = 0;
+		} else
+			m_index ++;
+
+		return save;
+	}
+
+	friend bool operator==(const AddressIterator &, const AddressIterator &) noexcept;
+	friend bool operator!=(const AddressIterator &, const AddressIterator &) noexcept;
+};
+
+/**
+ * Compare two address iterators.
+ *
+ * \param i1 the first iterator
+ * \param i2 the second iterator
+ * \return true if they equal
+ */
+inline bool operator==(const AddressIterator &i1, const AddressIterator &i2) noexcept
+{
+	return i1.m_addresses == i2.m_addresses && i1.m_index == i2.m_index;
+}
+
+/**
+ * Compare two address iterators.
+ *
+ * \param i1 the first iterator
+ * \param i2 the second iterator
+ * \return false if they equal
+ */
+inline bool operator!=(const AddressIterator &i1, const AddressIterator &i2) noexcept
+{
+	return !(i1 == i2);
+}
+
+} // !address
+
+/**
+ * \brief Predefined options.
+ */
+namespace option {
+
+/**
+ * \ingroup net-module-options
+ * \brief Set or get the blocking-mode for a socket.
+ * \warning On Windows, it's not possible to check if the socket is blocking or not.
+ */
+class SockBlockMode {
+private:
+	bool m_value;
+
+public:
+	/**
+	 * Create the option.
+	 *
+	 * By default the blocking mode is set to true.
+	 *
+	 * \param value set to true to make blocking sockets
+	 */
+	inline SockBlockMode(bool value = true) noexcept
+		: m_value(value)
+	{
+	}
+
+	/**
+	 * Set the option.
+	 *
+	 * \param sc the socket
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	void set(Socket<Address, Protocol> &sc) const
+	{
+#if defined(O_NONBLOCK) && !defined(_WIN32)
+		int flags;
+
+		if ((flags = fcntl(sc.handle(), F_GETFL, 0)) < 0)
+			flags = 0;
+
+		if (m_value)
+			flags &= ~(O_NONBLOCK);
+		else
+			flags |= O_NONBLOCK;
+
+		if (fcntl(sc.handle(), F_SETFL, flags) < 0)
+			throw Error(Error::System, "fcntl");
+#else
+		unsigned long flags = (m_value) ? 0 : 1;
+
+		if (ioctlsocket(sc.handle(), FIONBIO, &flags) == Failure)
+			throw Error(Error::System, "fcntl");
+#endif
+	}
+
+	/**
+	 * Get the option.
+	 *
+	 * \param sc the socket
+	 * \return the value
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	bool get(Socket<Address, Protocol> &sc) const
+	{
+#if defined(O_NONBLOCK) && !defined(_WIN32)
+		int flags = fcntl(sc.handle(), F_GETFL, 0);
+
+		if (flags < 0)
+			throw Error(Error::System, "fcntl");
+
+		return !(flags & O_NONBLOCK);
+#else
+		(void)sc;
+
+		throw Error(Error::Other, "get", std::strerror(ENOSYS));
+#endif
+	}
+};
+
+/**
+ * \ingroup net-module-options
+ * \brief Set or get the input buffer.
+ */
+class SockReceiveBuffer {
+private:
+	int m_value;
+
+public:
+	/**
+	 * Create the option.
+	 *
+	 * \param size the buffer size
+	 */
+	inline SockReceiveBuffer(int size = 2048) noexcept
+		: m_value(size)
+	{
+	}
+
+	/**
+	 * Set the option.
+	 *
+	 * \param sc the socket
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline void set(Socket<Address, Protocol> &sc) const
+	{
+		sc.set(SOL_SOCKET, SO_RCVBUF, m_value);
+	}
+
+	/**
+	 * Get the option.
+	 *
+	 * \param sc the socket
+	 * \return the value
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline int get(Socket<Address, Protocol> &sc) const
+	{
+		return sc.template get<int>(SOL_SOCKET, SO_RCVBUF);
+	}
+};
+
+/**
+ * \ingroup net-module-options
+ * \brief Reuse address, must be used before calling Socket::bind
+ */
+class SockReuseAddress {
+private:
+	bool m_value;
+
+public:
+	/**
+	 * Create the option.
+	 *
+	 * By default the option reuses the address.
+	 *
+	 * \param value set to true to reuse the address
+	 */
+	inline SockReuseAddress(bool value = true) noexcept
+		: m_value(value)
+	{
+	}
+
+	/**
+	 * Set the option.
+	 *
+	 * \param sc the socket
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline void set(Socket<Address, Protocol> &sc) const
+	{
+		sc.set(SOL_SOCKET, SO_REUSEADDR, m_value ? 1 : 0);
+	}
+
+	/**
+	 * Get the option.
+	 *
+	 * \param sc the socket
+	 * \return the value
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline bool get(Socket<Address, Protocol> &sc) const
+	{
+		return sc.template get<int>(SOL_SOCKET, SO_REUSEADDR) != 0;
+	}
+};
+
+/**
+ * \ingroup net-module-options
+ * \brief Set or get the output buffer.
+ */
+class SockSendBuffer {
+private:
+	int m_value;
+
+public:
+	/**
+	 * Create the option.
+	 *
+	 * \param size the buffer size
+	 */
+	inline SockSendBuffer(int size = 2048) noexcept
+		: m_value(size)
+	{
+	}
+
+	/**
+	 * Set the option.
+	 *
+	 * \param sc the socket
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline void set(Socket<Address, Protocol> &sc) const
+	{
+		sc.set(SOL_SOCKET, SO_SNDBUF, m_value);
+	}
+
+	/**
+	 * Get the option.
+	 *
+	 * \param sc the socket
+	 * \return the value
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline int get(Socket<Address, Protocol> &sc) const
+	{
+		return sc.template get<int>(SOL_SOCKET, SO_SNDBUF);
+	}
+};
+
+/**
+ * \ingroup net-module-options
+ * \brief Set this option if you want to disable nagle's algorithm.
+ */
+class TcpNoDelay {
+private:
+	bool m_value;
+
+public:
+	/**
+	 * Create the option.
+	 *
+	 * By default disable TCP delay.
+	 *
+	 * \param value set to true to disable TCP delay
+	 */
+	inline TcpNoDelay(bool value = true) noexcept
+		: m_value(value)
+	{
+	}
+
+	/**
+	 * Set the option.
+	 *
+	 * \param sc the socket
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline void set(Socket<Address, Protocol> &sc) const
+	{
+		sc.set(IPPROTO_TCP, TCP_NODELAY, m_value ? 1 : 0);
+	}
+
+	/**
+	 * Get the option.
+	 *
+	 * \param sc the socket
+	 * \return the value
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline bool get(Socket<Address, Protocol> &sc) const
+	{
+		return sc.template get<int>(IPPROTO_TCP, TCP_NODELAY) != 0;
+	}
+};
+
+/**
+ * \ingroup net-module-options
+ * \brief Control IPPROTO_IPV6/IPV6_V6ONLY
+ *
+ * Note: some systems may or not set this option by default so it's a good idea to set it in any case to either
+ * false or true if portability is a concern.
+ */
+class Ipv6Only {
+private:
+	bool m_value;
+
+public:
+	/**
+	 * Create the option.
+	 *
+	 * By default with want IPv6 only.
+	 *
+	 * \param value set to true to use IPv6 only
+	 */
+	inline Ipv6Only(bool value = true) noexcept
+		: m_value(value)
+	{
+	}
+
+	/**
+	 * Set the option.
+	 *
+	 * \param sc the socket
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline void set(Socket<Address, Protocol> &sc) const
+	{
+		sc.set(IPPROTO_IPV6, IPV6_V6ONLY, m_value ? 1 : 0);
+	}
+
+	/**
+	 * Get the option.
+	 *
+	 * \param sc the socket
+	 * \return the value
+	 * \throw Error on errors
+	 */
+	template <typename Address, typename Protocol>
+	inline bool get(Socket<Address, Protocol> &sc) const
+	{
+		return sc.template get<int>(IPPROTO_IPV6, IPV6_V6ONLY) != 0;
+	}
+};
+
+} // !option
+
+/**
+ * \brief Result of polling
+ *
+ * Result of a select call, returns the first ready socket found with its
+ * flags.
+ */
+class ListenerStatus {
+public:
+	Handle socket;		//!< which socket is ready
+	Condition flags;	//!< the flags
+};
+
+/**
+ * Table used in the socket listener to store which sockets have been
+ * set in which directions.
+ */
+using ListenerTable = std::unordered_map<Handle, Condition>;
+
+/**
+ * \brief Predefined backends for Listener.
+ */
+namespace backend {
+
+#if defined(NET_HAVE_EPOLL)
+
+/**
+ * \ingroup net-module-backends
+ * \brief Linux's epoll.
+ */
+class Epoll {
+private:
+	int m_handle{-1};
+	std::vector<epoll_event> m_events;
+
+	Epoll(const Epoll &) = delete;
+	Epoll &operator=(const Epoll &) = delete;
+
+	std::uint32_t toEpoll(Condition condition) const noexcept
+	{
+		std::uint32_t events = 0;
+
+		if ((condition & Condition::Readable) == Condition::Readable)
+			events |= EPOLLIN;
+		if ((condition & Condition::Writable) == Condition::Writable)
+			events |= EPOLLOUT;
+
+		return events;
+	}
+
+	Condition toCondition(std::uint32_t events) const noexcept
+	{
+		Condition condition = Condition::None;
+
+		if ((events & EPOLLIN) || (events & EPOLLHUP))
+			condition |= Condition::Readable;
+		if (events & EPOLLOUT)
+			condition |= Condition::Writable;
+
+		return condition;
+	}
+
+	void update(Handle h, int op, int eflags)
+	{
+		epoll_event ev;
+
+		std::memset(&ev, 0, sizeof (epoll_event));
+
+		ev.events = eflags;
+		ev.data.fd = h;
+
+		if (epoll_ctl(m_handle, op, h, &ev) < 0)
+			throw Error(Error::System, "epoll_ctl");
+	}
+
+public:
+	/**
+	 * Create epoll.
+	 *
+	 * \throw net::Error on failures
+	 */
+	inline Epoll()
+		: m_handle(epoll_create1(0))
+	{
+		if (m_handle < 0)
+			throw Error(Error::System, "epoll_create");
+	}
+
+	/**
+	 * Move constructor.
+	 *
+	 * \param other the other backend
+	 */
+	inline Epoll(Epoll &&other) noexcept
+		: m_handle(other.m_handle)
+	{
+		other.m_handle = -1;
+	}
+
+	/**
+	 * Close the kqueue descriptor.
+	 */
+	inline ~Epoll()
+	{
+		if (m_handle != -1)
+			close(m_handle);
+	}
+
+	/**
+	 * Get the backend name.
+	 *
+	 * \return kqueue
+	 */
+	inline std::string name() const noexcept
+	{
+		return "epoll";
+	}
+
+	/**
+	 * For set and unset, we need to apply the whole flags required, so if the socket
+	 * was set to Connection::Readable and user *8adds** Connection::Writable, we must
+	 * place both.
+	 *
+	 * \param table the listener table
+	 * \param h the handle
+	 * \param condition the condition
+	 * \param add set to true if the socket is new to the backend
+	 * \throw net::Error on failures
+	 */
+	void set(const ListenerTable &table, Handle h, Condition condition, bool add)
+	{
+		if (add) {
+			update(h, EPOLL_CTL_ADD, toEpoll(condition));
+			m_events.resize(m_events.size() + 1);
+		} else
+			update(h, EPOLL_CTL_MOD, toEpoll(table.at(h) | condition));
+	}
+
+	/**
+	 * Unset is a bit complicated case because Listener tells us which
+	 * flag to remove but to update epoll descriptor we need to pass
+	 * the effective flags that we want to be applied.
+	 *
+	 * So we put the same flags that are currently effective and remove the
+	 * requested one.
+	 *
+	 * \param table the listener table
+	 * \param h the handle
+	 * \param condition the condition
+	 * \param add set to true if the socket is new to the backend
+	 * \throw net::Error on failures
+	 */
+	void unset(const ListenerTable &table, Handle h, Condition condition, bool remove)
+	{
+		if (remove) {
+			update(h, EPOLL_CTL_DEL, 0);
+			m_events.resize(m_events.size() - 1);
+		} else
+			update(h, EPOLL_CTL_MOD, toEpoll(table.at(h) & ~(condition)));
+	}
+
+	/**
+	 * Wait for sockets to be ready.
+	 *
+	 * \param ms the milliseconds timeout
+	 * \return the sockets ready
+	 * \throw net::Error on failures
+	 */
+	std::vector<ListenerStatus> wait(const ListenerTable &, int ms)
+	{
+		int ret = epoll_wait(m_handle, m_events.data(), m_events.size(), ms);
+		std::vector<ListenerStatus> result;
+
+		if (ret == 0)
+			throw Error(Error::Timeout, "epoll_wait", std::strerror(ETIMEDOUT));
+		if (ret < 0)
+			throw Error(Error::System, "epoll_wait");
+
+		for (int i = 0; i < ret; ++i)
+			result.push_back(ListenerStatus{m_events[i].data.fd, toCondition(m_events[i].events)});
+
+		return result;
+	}
+
+	/**
+	 * Move operator.
+	 *
+	 * \param other the other
+	 * \return this
+	 */
+	inline Epoll &operator=(Epoll &&other)
+	{
+		m_handle = other.m_handle;
+		other.m_handle = -1;
+
+		return *this;
+	}
+};
+
+#endif // !NET_HAVE_EPOLL
+
+#if defined(NET_HAVE_KQUEUE)
+
+/**
+ * \ingroup net-module-backends
+ * \brief Implements kqueue(2).
+ *
+ * This implementation is available on all BSD and Mac OS X. It is better than
+ * poll(2) because it's O(1), however it's a bit more memory consuming.
+ */
+class Kqueue {
+private:
+	std::vector<struct kevent> m_result;
+	int m_handle;
+
+	Kqueue(const Kqueue &) = delete;
+	Kqueue &operator=(const Kqueue &) = delete;
+
+	void update(Handle h, int filter, int kflags)
+	{
+		struct kevent ev;
+
+		EV_SET(&ev, h, filter, kflags, 0, 0, nullptr);
+
+		if (kevent(m_handle, &ev, 1, nullptr, 0, nullptr) < 0)
+			throw Error(Error::System, "kevent");
+	}
+
+public:
+	/**
+	 * Create kqueue.
+	 *
+	 * \throw net::Error on failures
+	 */
+	inline Kqueue()
+		: m_handle(kqueue())
+	{
+		if (m_handle < 0)
+			throw Error(Error::System, "kqueue");
+	}
+
+	/**
+	 * Move constructor.
+	 *
+	 * \param other the other backend
+	 */
+	inline Kqueue(Kqueue &&other) noexcept
+		: m_handle(other.m_handle)
+	{
+		other.m_handle = -1;
+	}
+
+	/**
+	 * Close the kqueue descriptor.
+	 */
+	inline ~Kqueue()
+	{
+		if (m_handle != -1)
+			close(m_handle);
+	}
+
+	/**
+	 * Get the backend name.
+	 *
+	 * \return kqueue
+	 */
+	inline std::string name() const noexcept
+	{
+		return "kqueue";
+	}
+
+	/**
+	 * Set socket.
+	 *
+	 * \param h the handle
+	 * \param condition the condition
+	 * \param add set to true if the socket is new to the backend
+	 * \throw net::Error on failures
+	 */
+	void set(const ListenerTable &, Handle h, Condition condition, bool add)
+	{
+		if ((condition & Condition::Readable) == Condition::Readable)
+			update(h, EVFILT_READ, EV_ADD | EV_ENABLE);
+		if ((condition & Condition::Writable) == Condition::Writable)
+			update(h, EVFILT_WRITE, EV_ADD | EV_ENABLE);
+		if (add)
+			m_result.resize(m_result.size() + 1);
+	}
+
+	/**
+	 * Unset socket.
+	 *
+	 * \param h the handle
+	 * \param condition the condition
+	 * \param remove set to true if the socket is completely removed
+	 * \throw net::Error on failures
+	 */
+	void unset(const ListenerTable &, Handle h, Condition condition, bool remove)
+	{
+		if ((condition & Condition::Readable) == Condition::Readable)
+			update(h, EVFILT_READ, EV_DELETE);
+		if ((condition & Condition::Writable) == Condition::Writable)
+			update(h, EVFILT_WRITE, EV_DELETE);
+		if (remove)
+			m_result.resize(m_result.size() - 1);
+	}
+
+	/**
+	 * Wait for sockets to be ready.
+	 *
+	 * \param ms the milliseconds timeout
+	 * \return the sockets ready
+	 * \throw net::Error on failures
+	 */
+	std::vector<ListenerStatus> wait(const ListenerTable &, int ms)
+	{
+		std::vector<ListenerStatus> sockets;
+		timespec ts = { 0, 0 };
+		timespec *pts = (ms <= 0) ? nullptr : &ts;
+
+		ts.tv_sec = ms / 1000;
+		ts.tv_nsec = (ms % 1000) * 1000000;
+
+		int nevents = kevent(m_handle, nullptr, 0, &m_result[0], m_result.capacity(), pts);
+
+		if (nevents == 0)
+			throw Error(Error::Timeout, "kevent", std::strerror(ETIMEDOUT));
+		if (nevents < 0)
+			throw Error(Error::System, "kevent");
+
+		for (int i = 0; i < nevents; ++i) {
+			sockets.push_back(ListenerStatus{
+				static_cast<Handle>(m_result[i].ident),
+				m_result[i].filter == EVFILT_READ ? Condition::Readable : Condition::Writable
+			});
+		}
+
+		return sockets;
+	}
+
+	/**
+	 * Move operator.
+	 *
+	 * \param other the other
+	 * \return this
+	 */
+	inline Kqueue &operator=(Kqueue &&other) noexcept
+	{
+		m_handle = other.m_handle;
+		other.m_handle = -1;
+
+		return *this;
+	}
+};
+
+#endif // !NET_HAVE_KQUEUE
+
+#if defined(NET_HAVE_POLL)
+
+/**
+ * \ingroup net-module-backends
+ * \brief Implements poll(2).
+ *
+ * Poll is widely supported and is better than select(2). It is still not the
+ * best option as selecting the sockets is O(n).
+ */
+class Poll {
+private:
+	std::vector<pollfd> m_fds;
+
+	short toPoll(Condition condition) const noexcept
+	{
+		short result = 0;
+
+		if ((condition & Condition::Readable) == Condition::Readable)
+			result |= POLLIN;
+		if ((condition & Condition::Writable) == Condition::Writable)
+			result |= POLLOUT;
+
+		return result;
+	}
+
+	Condition toCondition(short &event) const noexcept
+	{
+		Condition condition = Condition::None;
+
+		/*
+		 * Poll implementations mark the socket differently regarding the disconnection of a socket.
+		 *
+		 * At least, even if POLLHUP or POLLIN is set, recv() always return 0 so we mark the socket as readable.
+		 */
+		if ((event & POLLIN) || (event & POLLHUP))
+			condition |= Condition::Readable;
+		if (event & POLLOUT)
+			condition |= Condition::Writable;
+
+		// Reset event for safety.
+		event = 0;
+
+		return condition;
+	}
+
+public:
+	/**
+	 * Get the backend name.
+	 *
+	 * \return kqueue
+	 */
+	inline std::string name() const noexcept
+	{
+		return "poll";
+	}
+
+	/**
+	 * Set socket.
+	 *
+	 * \param h the handle
+	 * \param condition the condition
+	 * \param add set to true if the socket is new to the backend
+	 * \throw net::Error on failures
+	 */
+	void set(const ListenerTable &, Handle h, Condition condition, bool add)
+	{
+		if (add)
+			m_fds.push_back(pollfd{h, toPoll(condition), 0});
+		else {
+			auto it = std::find_if(m_fds.begin(), m_fds.end(), [&] (const pollfd &pfd) {
+				return pfd.fd == h;
+			});
+
+			it->events |= toPoll(condition);
+		}
+	}
+
+	/**
+	 * Unset socket.
+	 *
+	 * \param h the handle
+	 * \param condition the condition
+	 * \param remove set to true if the socket is completely removed
+	 * \throw net::Error on failures
+	 */
+	void unset(const ListenerTable &, Handle h, Condition condition, bool remove)
+	{
+		auto it = std::find_if(m_fds.begin(), m_fds.end(), [&] (const pollfd &pfd) {
+			return pfd.fd == h;
+		});
+
+		if (remove)
+			m_fds.erase(it);
+		else
+			it->events &= ~(toPoll(condition));
+	}
+
+	/**
+	 * Wait for sockets to be ready.
+	 *
+	 * \param ms the milliseconds timeout
+	 * \return the sockets ready
+	 * \throw net::Error on failures
+	 */
+	std::vector<ListenerStatus> wait(const ListenerTable &, int ms)
+	{
+#if defined(_WIN32)
+		auto result = WSAPoll(m_fds.data(), (ULONG)m_fds.size(), ms);
+#else
+		auto result = poll(m_fds.data(), m_fds.size(), ms);
+#endif
+
+		if (result == 0)
+			throw Error(Error::Timeout, "select", std::strerror(ETIMEDOUT));
+		if (result < 0)
+			throw Error(Error::System, "poll");
+
+		std::vector<ListenerStatus> sockets;
+
+		for (auto &fd : m_fds)
+			if (fd.revents != 0)
+				sockets.push_back(ListenerStatus{fd.fd, toCondition(fd.revents)});
+
+		return sockets;
+	}
+};
+
+#endif // !NET_HAVE_POLL
+
+/**
+ * \ingroup net-module-backends
+ * \brief Implements select(2)
+ *
+ * This class is the fallback of any other method, it is not preferred at all for many reasons.
+ */
+class Select {
+public:
+	/**
+	 * Get the backend name.
+	 *
+	 * \return select
+	 */
+	inline std::string name() const
+	{
+		return "select";
+	}
+
+	/**
+	 * No-op.
+	 */
+	inline void set(const ListenerTable &, Handle, Condition, bool) noexcept
+	{
+	}
+
+	/**
+	 * No-op.
+	 */
+	inline void unset(const ListenerTable &, Handle, Condition, bool) noexcept
+	{
+	}
+
+	/**
+	 * Wait for sockets to be ready.
+	 *
+	 * \param table the listener table
+	 * \param ms the milliseconds timeout
+	 * \return the sockets ready
+	 * \throw net::Error on failures
+	 */
+	std::vector<ListenerStatus> wait(const ListenerTable &table, int ms)
+	{
+		timeval maxwait, *towait;
+		fd_set readset;
+		fd_set writeset;
+
+		FD_ZERO(&readset);
+		FD_ZERO(&writeset);
+
+		Handle max = 0;
+
+		for (const auto &pair : table) {
+			if ((pair.second & Condition::Readable) == Condition::Readable)
+				FD_SET(pair.first, &readset);
+			if ((pair.second & Condition::Writable) == Condition::Writable)
+				FD_SET(pair.first, &writeset);
+			if (pair.first > max)
+				max = pair.first;
+		}
+
+		maxwait.tv_sec = 0;
+		maxwait.tv_usec = ms * 1000;
+
+		// Set to nullptr for infinite timeout.
+		towait = (ms < 0) ? nullptr : &maxwait;
+
+		auto error = ::select(static_cast<int>(max + 1), &readset, &writeset, nullptr, towait);
+
+		if (error == Failure)
+			throw Error(Error::System, "select");
+		if (error == 0)
+			throw Error(Error::Timeout, "select", std::strerror(ETIMEDOUT));
+
+		std::vector<ListenerStatus> sockets;
+
+		for (const auto &pair : table) {
+			if (FD_ISSET(pair.first, &readset))
+				sockets.push_back(ListenerStatus{pair.first, Condition::Readable});
+			if (FD_ISSET(pair.first, &writeset))
+				sockets.push_back(ListenerStatus{pair.first, Condition::Writable});
+		}
+
+		return sockets;
+	}
+};
+
+} // !backend
+
+/**
+ * \brief Synchronous multiplexing
+ *
+ * Convenient wrapper around the select() system call.
+ *
+ * This class is implemented using a bridge pattern to allow different uses
+ * of listener implementation.
+ *
+ * You should not reinstanciate a new Listener at each iteartion of your
+ * main loop as it can be extremely costly. Instead use the same listener that
+ * you can safely modify on the fly.
+ *
+ * Currently, poll, epoll, select and kqueue are available.
+ */
+template <typename Backend = backend :: NET_DEFAULT_BACKEND>
+class Listener {
+private:
+	Backend m_backend;
+	ListenerTable m_table;
+
+public:
+	/**
+	 * Construct an empty listener.
+	 */
+	Listener() = default;
+
+	/**
+	 * Get the backend.
+	 *
+	 * \return the backend
+	 */
+	inline const Backend &backend() const noexcept
+	{
+		return m_backend;
+	}
+
+	/**
+	 * Get the non-modifiable table.
+	 *
+	 * \return the table
+	 */
+	inline const ListenerTable &table() const noexcept
+	{
+		return m_table;
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \return the iterator
+	 */
+	inline ListenerTable::const_iterator begin() const noexcept
+	{
+		return m_table.begin();
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \return the iterator
+	 */
+	inline ListenerTable::const_iterator cbegin() const noexcept
+	{
+		return m_table.cbegin();
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \return the iterator
+	 */
+	inline ListenerTable::const_iterator end() const noexcept
+	{
+		return m_table.end();
+	}
+
+	/**
+	 * Overloaded function.
+	 *
+	 * \return the iterator
+	 */
+	inline ListenerTable::const_iterator cend() const noexcept
+	{
+		return m_table.cend();
+	}
+
+	/**
+	 * Add or update a socket to the listener.
+	 *
+	 * If the socket is already placed with the appropriate flags, the
+	 * function is a no-op.
+	 *
+	 * If incorrect flags are passed, the function does nothing.
+	 *
+	 * \param sc the socket
+	 * \param condition the condition (may be OR'ed)
+	 * \throw Error if the backend failed to set
+	 */
+	void set(Handle sc, Condition condition)
+	{
+		// Invalid or useless flags.
+		if (condition == Condition::None || static_cast<int>(condition) > 0x3)
+			return;
+
+		auto it = m_table.find(sc);
+
+		// Do not update the table if the backend failed to add or update.
+		if (it == m_table.end()) {
+			m_backend.set(m_table, sc, condition, true);
+			m_table.emplace(sc, condition);
+		} else {
+			// Remove flag if already present.
+			if ((condition & Condition::Readable) == Condition::Readable &&
+			    (it->second & Condition::Readable) == Condition::Readable)
+				condition &= ~(Condition::Readable);
+			if ((condition & Condition::Writable) == Condition::Writable &&
+			    (it->second & Condition::Writable) == Condition::Writable)
+				condition &= ~(Condition::Writable);
+
+			// Still need a call?
+			if (condition != Condition::None) {
+				m_backend.set(m_table, sc, condition, false);
+				it->second |= condition;
+			}
+		}
+	}
+
+	/**
+	 * Unset a socket from the listener, only the flags is removed
+	 * unless the two flagss are requested.
+	 *
+	 * For example, if you added a socket for both reading and writing,
+	 * unsetting the write flags will keep the socket for reading.
+	 *
+	 * \param sc the socket
+	 * \param condition the condition (may be OR'ed)
+	 * \see remove
+	 */
+	void unset(Handle sc, Condition condition)
+	{
+		auto it = m_table.find(sc);
+
+		// Invalid or useless flags.
+		if (condition == Condition::None || static_cast<int>(condition) > 0x3 || it == m_table.end())
+			return;
+
+		// Like set, do not update if the socket is already at the appropriate state.
+		if ((condition & Condition::Readable) == Condition::Readable &&
+		    (it->second & Condition::Readable) != Condition::Readable)
+			condition &= ~(Condition::Readable);
+		if ((condition & Condition::Writable) == Condition::Writable &&
+		    (it->second & Condition::Writable) != Condition::Writable)
+			condition &= ~(Condition::Writable);
+
+		if (condition != Condition::None) {
+			// Determine if it's a complete removal.
+			bool removal = ((it->second) & ~(condition)) == Condition::None;
+
+			m_backend.unset(m_table, sc, condition, removal);
+
+			if (removal)
+				m_table.erase(it);
+			else
+				it->second &= ~(condition);
+		}
+	}
+
+	/**
+	 * Remove completely the socket from the listener.
+	 *
+	 * It is a shorthand for unset(sc, Condition::Readable | Condition::Writable);
+	 *
+	 * \param sc the socket
+	 */
+	inline void remove(Handle sc)
+	{
+		unset(sc, Condition::Readable | Condition::Writable);
+	}
+
+	/**
+	 * Remove all sockets.
+	 */
+	inline void clear()
+	{
+		while (!m_table.empty())
+			remove(m_table.begin()->first);
+	}
+
+	/**
+	 * Get the number of sockets in the listener.
+	 *
+	 * \return the number of sockets
+	 */
+	inline ListenerTable::size_type size() const noexcept
+	{
+		return m_table.size();
+	}
+
+	/**
+	 * Select a socket. Waits for a specific amount of time specified as the duration.
+	 *
+	 * \param duration the duration
+	 * \return the socket ready
+	 */
+	template <typename Rep, typename Ratio>
+	inline ListenerStatus wait(const std::chrono::duration<Rep, Ratio> &duration)
+	{
+		auto cvt = std::chrono::duration_cast<std::chrono::milliseconds>(duration);
+		auto max = cvt.count() > INT_MAX ? INT_MAX : static_cast<int>(cvt.count());
+
+		return m_backend.wait(m_table, max)[0];
+	}
+
+	/**
+	 * Overload with milliseconds.
+	 *
+	 * \param timeout the optional timeout in milliseconds
+	 * \return the socket ready
+	 */
+	inline ListenerStatus wait(long long int timeout = -1)
+	{
+		return wait(std::chrono::milliseconds(timeout));
+	}
+
+	/**
+	 * Select multiple sockets.
+	 *
+	 * \param duration the duration
+	 * \return the socket ready
+	 */
+	template <typename Rep, typename Ratio>
+	inline std::vector<ListenerStatus> waitMultiple(const std::chrono::duration<Rep, Ratio> &duration)
+	{
+		auto cvt = std::chrono::duration_cast<std::chrono::milliseconds>(duration);
+
+		return m_backend.wait(m_table, cvt.count());
+	}
+
+	/**
+	 * Overload with milliseconds.
+	 *
+	 * \param timeout the optional timeout in milliseconds
+	 * \return the socket ready
+	 */
+	inline std::vector<ListenerStatus> waitMultiple(int timeout = -1)
+	{
+		return waitMultiple(std::chrono::milliseconds(timeout));
+	}
+};
+
+/**
+ * \ingroup net-module-tcp
+ * \brief Helper to create TCP sockets.
+ */
+template <typename Address>
+using SocketTcp = Socket<Address, protocol::Tcp>;
+
+/**
+ * \ingroup net-module-tcp
+ * \brief Helper to create TCP/Ipv4 or TCP/Ipv6 sockets.
+ */
+using SocketTcpIp = Socket<address::Ip, protocol::Tcp>;
+
+/**
+ * \ingroup net-module-tcp
+ * \brief Helper to create TCP/Ipv4 sockets.
+ */
+using SocketTcpIpv4 = Socket<address::Ipv4, protocol::Tcp>;
+
+/**
+ * \ingroup net-module-tcp
+ * \brief Helper to create TCP/Ipv6 sockets.
+ */
+using SocketTcpIpv6 = Socket<address::Ipv6, protocol::Tcp>;
+
+/**
+ * \ingroup net-module-udp
+ * \brief Helper to create UDP sockets.
+ */
+template <typename Address>
+using SocketUdp = Socket<Address, protocol::Udp>;
+
+/**
+ * \ingroup net-module-udp
+ * \brief Helper to create UDP/Ipv4 or UDP/Ipv6 sockets.
+ */
+using SocketUdpIp = Socket<address::Ip, protocol::Udp>;
+
+/**
+ * \ingroup net-module-udp
+ * \brief Helper to create UDP/Ipv4 sockets.
+ */
+using SocketUdpIpv4 = Socket<address::Ipv4, protocol::Udp>;
+
+/**
+ * \ingroup net-module-udp
+ * \brief Helper to create UDP/Ipv6 sockets.
+ */
+using SocketUdpIpv6 = Socket<address::Ipv6, protocol::Udp>;
+
+#if !defined(_WIN32)
+
+/**
+ * \ingroup net-module-tcp
+ * \brief Helper to create TCP/Local sockets.
+ */
+using SocketTcpLocal = Socket<address::Local, protocol::Tcp>;
+
+/**
+ * \ingroup net-module-udp
+ * \brief Helper to create UDP/Local sockets.
+ */
+using SocketUdpLocal = Socket<address::Local, protocol::Udp>;
+
+#endif
+
+#if !defined(NET_NO_SSL)
+
+/**
+ * \ingroup net-module-tls
+ * \brief Helper to create TLS sockets.
+ */
+template <typename Address>
+using SocketTls = Socket<Address, protocol::Tls>;
+
+/**
+ * \ingroup net-module-tls
+ * \brief Helper to create TLS/Ipv4 or TLS/Ipv6 sockets.
+ */
+using SocketTlsIp = Socket<address::Ip, protocol::Tls>;
+
+/**
+ * \ingroup net-module-tls
+ * \brief Helper to create TLS/Ipv4 sockets.
+ */
+using SocketTlsIpv4 = Socket<address::Ipv4, protocol::Tls>;
+
+/**
+ * \ingroup net-module-tls
+ * \brief Helper to create TLS/Ipv6 sockets.
+ */
+using SocketTlsIpv6 = Socket<address::Ipv6, protocol::Tls>;
+
+#endif
+
+/**
+ * \ingroup net-module-resolv
+ *
+ * Resolve an hostname immediately.
+ *
+ * \param host the hostname
+ * \param service the service (e.g. http or port number)
+ * \param domain the domain (e.g. AF_INET)
+ * \param type the type (e.g. SOCK_STREAM)
+ * \return the address iterator
+ * \throw net::Error on failures
+ */
+inline address::AddressIterator resolve(const std::string &host, const std::string &service, int domain = AF_UNSPEC, int type = 0)
+{
+#if !defined(NET_NO_AUTO_INIT)
+		net::init();
+#endif
+
+	struct addrinfo hints, *res, *p;
+
+	std::memset(&hints, 0, sizeof (hints));
+	hints.ai_family = domain;
+	hints.ai_socktype = type;
+
+	int e = getaddrinfo(host.c_str(), service.c_str(), &hints, &res);
+
+	if (e != 0)
+		throw Error(Error::System, "getaddrinfo", gai_strerror(e));
+
+	std::vector<address::Generic> addresses;
+
+	for (p = res; p != nullptr; p = p->ai_next)
+		addresses.push_back(address::Generic(p->ai_addr, p->ai_addrlen));
+
+	return address::AddressIterator(addresses, 0);
+}
+
+/**
+ * \ingroup net-module-resolv
+ *
+ * Overloaded function.
+ *
+ * \param sc the parent socket
+ * \param host the hostname
+ * \param service the service name
+ * \return the address iterator
+ * \throw net::Error on failures
+ */
+template <typename Address, typename Protocol>
+address::AddressIterator resolve(const Socket<Address, Protocol> &sc, const std::string &host, const std::string &service)
+{
+	return resolve(host, service, Address().domain(), sc.protocol().type());
+}
+
+/**
+ * \ingroup net-module-resolv
+ *
+ * Resolve the first address.
+ *
+ * \param host the hostname
+ * \param service the service name
+ * \param domain the domain (e.g. AF_INET)
+ * \param type the type (e.g. SOCK_STREAM)
+ * \return the first generic address available
+ * \throw net::Error on failures
+ * \note do not use AF_UNSPEC and 0 as type for this function
+ */
+inline address::Generic resolveOne(const std::string &host, const std::string &service, int domain, int type)
+{
+	address::AddressIterator end;
+	address::AddressIterator it = resolve(host, service, domain, type);
+
+	if (it == end)
+		throw Error(Error::Other, "resolveOne", "no address available");
+
+	return *it;
+}
+
+/**
+ * \ingroup net-module-resolv
+ *
+ * Overloaded function
+ *
+ * \param sc the parent socket
+ * \param host the hostname
+ * \param service the service name
+ * \return the first generic address available
+ * \throw net::Error on failures
+ */
+template <typename Address, typename Protocol>
+address::Generic resolveOne(const Socket<Address, Protocol> &sc, const std::string &host, const std::string &service)
+{
+	return resolveOne(host, service, Address().domain(), sc.protocol().type());
+}
+
+} // !net
+
+#endif // !NET_HPP