The server component depends on libuv, so libvws must have been built with the server enabled; the example builds against that and the examples' libvwsx. Run it and it listens on 127.0.0.1 port 8183, echoing back the raw bytes of whatever is sent to it:

$ ./server-core
server-core: raw echo server on 127.0.0.1:8183 (Ctrl-C to stop)

Because this is the raw data layer, it performs no WebSocket handshake; it is the foundation on which the WebSocket, HTTP and message servers of the following chapters are built. Press Ctrl-C to stop it.