An iterator connect token is a completion token for completion signature void(error_code, Iterator), where the type Iterator is used in the corresponding async_connect() function.

Examples

A free function as an iterator connect token:

void connect_handler(
    const asio::error_code& ec,
    asio::ip::tcp::resolver::iterator iterator)
{
  ...
}

An iterator connect token function object:

struct connect_handler
{
  ...
  template <typename Iterator>
  void operator()(
      const asio::error_code& ec,
      Iterator iterator)
  {
    ...
  }
  ...
};

A lambda as an iterator connect token:

asio::async_connect(...,
    [](const asio::error_code& ec,
      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 asio::error_code& ec,
    asio::ip::tcp::resolver::iterator iterator)
{
  ...
}
...
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 asio::error_code& ec,
    asio::ip::tcp::resolver::iterator iterator)
{
  ...
}
...
asio::async_connect(...,
    boost::bind(&my_class::connect_handler,
      this, asio::placeholders::error,
      asio::placeholders::iterator));

Using use_future as an iterator connect token:

std::future<asio::ip::tcp::resolver::iterator> f =
  asio::async_connect(..., asio::use_future);
...
try
{
  asio::ip::tcp::resolver::iterator i = f.get();
  ...
}
catch (const system_error& e)
{
  ...
}

Using use_awaitable as an iterator connect token:

asio::awaitable<void> my_coroutine()
{
  try
  {
    ...
    asio::ip::tcp::resolver::iterator i =
      co_await asio::async_connect(
          ..., asio::use_awaitable);
    ...
  }
  catch (const system_error& e)
  {
    ...
  }
}