A composed connect handler must meet the requirements for a handler. A value h of a composed connect handler class should work correctly in the expression h(ec, i), where ec is an lvalue of type const error_code and i is an lvalue of the type Iterator used in the corresponding connect() or async_connect()` function.

Examples

A free function as a composed connect handler:

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

A composed connect handler function object:

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

A non-static class member function adapted to a composed connect handler using 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));