Asynchronously establishes a socket connection by trying each endpoint in a sequence. More...

Functions
template<typename Protocol , typename SocketService , typename Iterator , typename ComposedConnectHandler >
	boost::asio::BOOST_ASIO_INITFN_RESULT_TYPE (ComposedConnectHandler, void(boost::system::error_code, Iterator)) async_connect(basic_socket< Protocol
	Asynchronously establishes a socket connection by trying each endpoint in a sequence. More...

SocketService Iterator	boost::asio::BOOST_ASIO_MOVE_ARG (ComposedConnectHandler) handler)

template<typename Protocol , typename SocketService , typename Iterator , typename ConnectCondition , typename ComposedConnectHandler >
	boost::asio::BOOST_ASIO_INITFN_RESULT_TYPE (ComposedConnectHandler, void(boost::system::error_code, Iterator)) async_connect(basic_socket< Protocol
	Asynchronously establishes a socket connection by trying each endpoint in a sequence. More...

Variables
SocketService &	boost::asio::s

SocketService Iterator	boost::asio::begin

SocketService Iterator Iterator	boost::asio::end

SocketService Iterator ConnectCondition	boost::asio::connect_condition

Detailed Description

Asynchronously establishes a socket connection by trying each endpoint in a sequence.

Function Documentation

template<typename Protocol , typename SocketService , typename Iterator , typename ComposedConnectHandler >

boost::asio::BOOST_ASIO_INITFN_RESULT_TYPE	(	ComposedConnectHandler	,
		void(boost::system::error_code, Iterator)
	)

#include <boost_1_57_0/boost/asio/connect.hpp>

Asynchronously establishes a socket connection by trying each endpoint in a sequence.

This function attempts to connect a socket to one of a sequence of endpoints. It does this by repeated calls to the socket's async_connect member function, once for each endpoint in the sequence, until a connection is successfully established.

Parameters

s	The socket to be connected. If the socket is already open, it will be closed.
begin	An iterator pointing to the start of a sequence of endpoints.
handler	The handler to be called when the connect operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. if the sequence is empty, set to // boost::asio::error::not_found. Otherwise, contains the // error from the last connection attempt. const boost::system::error_code& error, // On success, an iterator denoting the successfully // connected endpoint. Otherwise, the end iterator. Iterator iterator ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using boost::asio::io_service::post().

Note: This overload assumes that a default constructed object of type Iterator represents the end of the sequence. This is a valid assumption for iterator types such as boost::asio::ip::tcp::resolver::iterator.

Example: tcp::resolver r(io_service);

tcp::resolver::query q("host", "service");

tcp::socket s(io_service);

// ...

r.async_resolve(q, resolve_handler);

// ...

void resolve_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

if (!ec)

{

boost::asio::async_connect(s, i, connect_handler);

}

}

// ...

void connect_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

// ...

}

This function attempts to connect a socket to one of a sequence of endpoints. It does this by repeated calls to the socket's async_connect member function, once for each endpoint in the sequence, until a connection is successfully established.

Parameters

s	The socket to be connected. If the socket is already open, it will be closed.
begin	An iterator pointing to the start of a sequence of endpoints.
end	An iterator pointing to the end of a sequence of endpoints.
handler	The handler to be called when the connect operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. if the sequence is empty, set to // boost::asio::error::not_found. Otherwise, contains the // error from the last connection attempt. const boost::system::error_code& error, // On success, an iterator denoting the successfully // connected endpoint. Otherwise, the end iterator. Iterator iterator ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using boost::asio::io_service::post().

Example: tcp::resolver r(io_service);

tcp::resolver::query q("host", "service");

tcp::socket s(io_service);

// ...

r.async_resolve(q, resolve_handler);

// ...

void resolve_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

if (!ec)

{

tcp::resolver::iterator end;

boost::asio::async_connect(s, i, end, connect_handler);

}

}

// ...

void connect_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

// ...

}

template<typename Protocol , typename SocketService , typename Iterator , typename ConnectCondition , typename ComposedConnectHandler >

boost::asio::BOOST_ASIO_INITFN_RESULT_TYPE	(	ComposedConnectHandler	,
		void(boost::system::error_code, Iterator)
	)

#include <boost_1_57_0/boost/asio/connect.hpp>

Asynchronously establishes a socket connection by trying each endpoint in a sequence.

This function attempts to connect a socket to one of a sequence of endpoints. It does this by repeated calls to the socket's async_connect member function, once for each endpoint in the sequence, until a connection is successfully established.

Parameters

s	The socket to be connected. If the socket is already open, it will be closed.
begin	An iterator pointing to the start of a sequence of endpoints.
connect_condition	A function object that is called prior to each connection attempt. The signature of the function object must be: Iterator connect_condition( const boost::system::error_code& ec, Iterator next); The `ec` parameter contains the result from the most recent connect operation. Before the first connection attempt, `ec` is always set to indicate success. The `next` parameter is an iterator pointing to the next endpoint to be tried. The function object should return the next iterator, but is permitted to return a different iterator so that endpoints may be skipped. The implementation guarantees that the function object will never be called with the end iterator.
handler	The handler to be called when the connect operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. if the sequence is empty, set to // boost::asio::error::not_found. Otherwise, contains the // error from the last connection attempt. const boost::system::error_code& error, // On success, an iterator denoting the successfully // connected endpoint. Otherwise, the end iterator. Iterator iterator ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using boost::asio::io_service::post().

Note: This overload assumes that a default constructed object of type Iterator represents the end of the sequence. This is a valid assumption for iterator types such as boost::asio::ip::tcp::resolver::iterator.

Example: The following connect condition function object can be used to output information about the individual connection attempts:
struct my_connect_condition

{

template <typename Iterator>

Iterator operator()(

const boost::system::error_code& ec,

Iterator next)

{

if (ec) std::cout << "Error: " << ec.message() << std::endl;

std::cout << "Trying: " << next->endpoint() << std::endl;

return next;

}

};

It would be used with the boost::asio::connect function as follows:
tcp::resolver r(io_service);

tcp::resolver::query q("host", "service");

tcp::socket s(io_service);

// ...

r.async_resolve(q, resolve_handler);

// ...

void resolve_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

if (!ec)

{

boost::asio::async_connect(s, i,

my_connect_condition(),

connect_handler);

}

}

// ...

void connect_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

if (ec)

{

// An error occurred.

}

else

{

std::cout << "Connected to: " << i->endpoint() << std::endl;

}

}

This function attempts to connect a socket to one of a sequence of endpoints. It does this by repeated calls to the socket's async_connect member function, once for each endpoint in the sequence, until a connection is successfully established.

Parameters

s	The socket to be connected. If the socket is already open, it will be closed.
begin	An iterator pointing to the start of a sequence of endpoints.
end	An iterator pointing to the end of a sequence of endpoints.
connect_condition	A function object that is called prior to each connection attempt. The signature of the function object must be: Iterator connect_condition( const boost::system::error_code& ec, Iterator next); The `ec` parameter contains the result from the most recent connect operation. Before the first connection attempt, `ec` is always set to indicate success. The `next` parameter is an iterator pointing to the next endpoint to be tried. The function object should return the next iterator, but is permitted to return a different iterator so that endpoints may be skipped. The implementation guarantees that the function object will never be called with the end iterator.
handler	The handler to be called when the connect operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. if the sequence is empty, set to // boost::asio::error::not_found. Otherwise, contains the // error from the last connection attempt. const boost::system::error_code& error, // On success, an iterator denoting the successfully // connected endpoint. Otherwise, the end iterator. Iterator iterator ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using boost::asio::io_service::post().

Example: The following connect condition function object can be used to output information about the individual connection attempts:
struct my_connect_condition

{

template <typename Iterator>

Iterator operator()(

const boost::system::error_code& ec,

Iterator next)

{

if (ec) std::cout << "Error: " << ec.message() << std::endl;

std::cout << "Trying: " << next->endpoint() << std::endl;

return next;

}

};

It would be used with the boost::asio::connect function as follows:
tcp::resolver r(io_service);

tcp::resolver::query q("host", "service");

tcp::socket s(io_service);

// ...

r.async_resolve(q, resolve_handler);

// ...

void resolve_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

if (!ec)

{

tcp::resolver::iterator end;

boost::asio::async_connect(s, i, end,

my_connect_condition(),

connect_handler);

}

}

// ...

void connect_handler(

const boost::system::error_code& ec,

tcp::resolver::iterator i)

{

if (ec)

{

// An error occurred.

}

else

{

std::cout << "Connected to: " << i->endpoint() << std::endl;

}

}

SocketService Iterator boost::asio::BOOST_ASIO_MOVE_ARG ( ComposedConnectHandler )

#include <boost_1_57_0/boost/asio/connect.hpp>

Variable Documentation

SocketService Iterator boost::asio::begin

#include <boost_1_57_0/boost/asio/connect.hpp>

SocketService Iterator Iterator ConnectCondition boost::asio::connect_condition

#include <boost_1_57_0/boost/asio/connect.hpp>

SocketService Iterator Iterator boost::asio::end

#include <boost_1_57_0/boost/asio/connect.hpp>

SocketService & boost::asio::s

#include <boost_1_57_0/boost/asio/connect.hpp>

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation