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[/
/ Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
/
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
/]
[section:IteratorConnectToken Iterator connect token requirements]
An iterator connect token is a [link boost_asio.overview.model.completion_tokens
completion token] for completion signature `void(error_code, Iterator)`, where
the type `Iterator` is used in the corresponding `async_connect()` function.
[heading Examples]
A free function as an iterator connect token:
void connect_handler(
const boost::system::error_code& ec,
boost::asio::ip::tcp::resolver::iterator iterator)
{
...
}
An iterator connect token function object:
struct connect_handler
{
...
template <typename Iterator>
void operator()(
const boost::system::error_code& ec,
Iterator iterator)
{
...
}
...
};
A lambda as an iterator connect token:
boost::asio::async_connect(...,
[](const boost::system::error_code& ec,
boost::asio::ip::tcp::resolver::iterator iterator)
{
...
});
A non-static class member function adapted to an iterator connect token using
`std::bind()`:
void my_class::connect_handler(
const boost::system::error_code& ec,
boost::asio::ip::tcp::resolver::iterator iterator)
{
...
}
...
boost::asio::async_connect(...,
std::bind(&my_class::connect_handler,
this, std::placeholders::_1,
std::placeholders::_2));
A non-static class member function adapted to an iterator connect token using
`boost::bind()`:
void my_class::connect_handler(
const boost::system::error_code& ec,
boost::asio::ip::tcp::resolver::iterator iterator)
{
...
}
...
boost::asio::async_connect(...,
boost::bind(&my_class::connect_handler,
this, boost::asio::placeholders::error,
boost::asio::placeholders::iterator));
Using [link boost_asio.reference.use_future use_future] as an iterator connect token:
std::future<boost::asio::ip::tcp::resolver::iterator> f =
boost::asio::async_connect(..., boost::asio::use_future);
...
try
{
boost::asio::ip::tcp::resolver::iterator i = f.get();
...
}
catch (const system_error& e)
{
...
}
Using [link boost_asio.reference.use_awaitable use_awaitable] as an iterator connect
token:
boost::asio::awaitable<void> my_coroutine()
{
try
{
...
boost::asio::ip::tcp::resolver::iterator i =
co_await boost::asio::async_connect(
..., boost::asio::use_awaitable);
...
}
catch (const system_error& e)
{
...
}
}
[endsect]
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