...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
An iterator connect handler must meet the requirements for a handler.
A value h
of an iterator 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.
A free function as an iterator connect handler:
void connect_handler( const boost::system::error_code& ec, boost::asio::ip::tcp::resolver::iterator iterator) { ... }
An iterator connect handler function object:
struct connect_handler { ... template <typename Iterator> void operator()( const boost::system::error_code& ec, Iterator iterator) { ... } ... };
A lambda as an iterator connect handler:
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 handler
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 handler
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));