AF_UNIX support for Windows 10

[ghost]

@cryptocode commented on May 27, 2018, 10:03 PM UTC:

The April update of Windows 10 includes AF_UNIX (domain sockets) support, and asio should support it.

BOOST_ASIO_HAS_LOCAL_SOCKETS would thus be true on recent Windows 10 hosts.

This issue was moved by chriskohlhoff from boostorg/asio#119.

[youyuanwu]

asio already works with Windows AF_UNIX. Example:
Server:

        std::filesystem::remove("my.sock");
        asio::io_context ioc{1};
        asio::local::stream_protocol::endpoint ep("my.sock");
        asio::local::stream_protocol::acceptor acceptor(ioc, ep, false/*reuse addr*/);
        asio::local::stream_protocol::socket socket(ioc);
        http_server(acceptor, socket); // see beast http server example
        ioc.run();

Client

        net::io_context ioc;
        net::local::stream_protocol::socket sock(ioc);
        sock.connect("my.sock");
        http::request<http::string_body> req{http::verb::get, "/count", 11};
        http::write(sock, req);

Caveats:

asio::local::stream_protocol::acceptor acceptor(ioc, ep, false/*reuse addr*/);

• acceptor reuse addr must be false.
  If it is set to true, SO_REUSEADDR will be set on the socket using setsockopt, and winsock bind function will fail.
  SO_REUSEADDR set to true works on linux. But I don't think this opt applies to AF_UNIX, you can search online to see various discussion about SO_REUSEADDR and AF_UNIX.
• You need to remove the socket file before open the socket(making the acceptor), in linux use ::unlink().