Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Open the acceptor using the specified protocol.

void open(
    const protocol_type & protocol = protocol_type());

This function opens the socket acceptor so that it will use the specified protocol.

boost::asio::ip::tcp::acceptor acceptor(my_context);
acceptor.open(boost::asio::ip::tcp::v4());