Erlang TCP服务器始终在接受时关闭

我对Erlang还相当陌生，我正在尝试建立一个简单的多客户端聊天服务器来学习更多关于该语言的知识。但是，每当我尝试运行它时，就会在侦听套接字上调用gen_tcp:accept时出现套接字关闭错误。我尝试了许多不同的端口号，但都没有用。我错过了什么

代码如下：

-define(TCP_OPTIONS, [binary, {packet, 2}, {active, false}, {reuseaddr, true}]).

listen(Portno, DictPid) -> 
  case gen_tcp:listen(Portno, ?TCP_OPTIONS) of
    {ok, ListenSocket} ->
      spawn_link(fun() -> accept_connections(ListenSocket, DictPid) end),
      io:format("Listening on ~p~n", [ListenSocket]);
    {error, Error} ->
      io:format("Listen Error: ~w~n", [Error])
  end.

accept_connections(ListenSocket, DictPid) ->
  case gen_tcp:accept(ListenSocket) of
    {ok, ClientSocket} ->
      io:format("Accepting:~w~n", [ClientSocket]),
      gen_tcp:send(ClientSocket, "Welcome! Enter your name~n"),
      ClientPid = spawn(fun() -> io:format("Client connected"),
                                 setup_user(ClientSocket, DictPid) end),
      gen_tcp:controlling_process(ClientSocket, ClientPid),
      accept_connections(ListenSocket, DictPid);
    {error, Error} ->
      io:format("Accept Error: ~w~n", [Error])
  end.
  
setup_user(ClientSocket, DictPid) ->
  {ok, Username} = gen_tcp:recv(ClientSocket, 0),
  DictPid ! {add_new_pair, ClientSocket, Username},
  ClientDict = get_dict(DictPid),
  broadcast_message(dict:fetch_keys(ClientDict), "[" ++ Username ++ "has entered the chat]"),
  client_loop(ClientSocket, Username, DictPid).

[rest of program]

---

这里的问题是

ListenSocket

的控制器终止，这导致

ListenSocket

关闭。

您可能需要从文档

https://erlang.org/doc/man/gen_tcp.html#examples