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

Disable sends or receives on the socket.

void shutdown(
    shutdown_type what);

This function is used to disable send operations, receive operations, or both.

Shutting down the send side of the socket:

boost::asio::ip::tcp::socket socket(io_service);
...
socket.shutdown(boost::asio::ip::tcp::socket::shutdown_send);