mongoose/docs/c-api/http.h/mg_send_websocket_handshake2.md

title	decl_name	symbol_kind	signature
mg_send_websocket_handshake2()	mg_send_websocket_handshake2	func	void mg_send_websocket_handshake2(struct mg_connection *nc, const char *path, const char *host, const char *protocol, const char *extra_headers);

Send WebSocket handshake to the server.

nc must be a valid connection, connected to a server. uri is an URI to fetch, host goes into the Host header, protocol goes into the Sec-WebSocket-Proto header (NULL to omit), extra_headers is an extra HTTP header to send or NULL.

This function is intended to be used by the WebSocket client.