Asynchronously establishes a socket connection by trying each endpoint in a sequence.
template< typename Protocol, typename Iterator, typename IteratorConnectHandler> DEDUCED async_connect( basic_socket< Protocol > & s, Iterator begin, Iterator end, IteratorConnectHandler && handler);
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.
The socket to be connected. If the socket is already open, it will be closed.
An iterator pointing to the start of a sequence of endpoints.
An iterator pointing to the end of a sequence of endpoints.
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 // asio::error::not_found. Otherwise, contains the // error from the last connection attempt. const asio::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 asio::io_context::post()
.
std::vector<tcp::endpoint> endpoints = ...; tcp::socket s(io_context); asio::async_connect(s, endpoints.begin(), endpoints.end(), connect_handler); // ... void connect_handler( const asio::error_code& ec, std::vector<tcp::endpoint>::iterator i) { // ... }