Erlangのメソッドでタイムアウトを適用するには？

Question

、簡単なモジュールのメソッド呼び出しに一例として をタイムアウトを適用する方法はあり、

私は上記の方法にタイムアウトオプションを追加したい

my_method(Name)-> 
    timer:sleep(2000), 
    io:format("hello world ~p!~n",[Name]). 

、それを行う方法はありますか？

Answer 1

あなたの関数を生成し、メッセージを返すのを待つことができます。受信を待つ間にタイムアウトを設定することができます。

my_method(Name)-> 
    YourTimeOut = 10, 
    Self = self(), 
    _Pid = spawn(fun()-> 
        timer:sleep(2000), 
        io:format("hello world ~p!~n",[Name]), 
        Self ! {self(), ok} end), 
    receive 
    {_PidSpawned, ok} -> ok 
    after 
    YourTimeOut -> timout 
    end. 

Answer 2

gen:call/3,4の実装を参照してください。それは行われます

do_call(Process, Label, Request, Timeout) -> 
    try erlang:monitor(process, Process) of 
    Mref -> 
     %% If the monitor/2 call failed to set up a connection to a 
     %% remote node, we don't want the '!' operator to attempt 
     %% to set up the connection again. (If the monitor/2 call 
     %% failed due to an expired timeout, '!' too would probably 
     %% have to wait for the timeout to expire.) Therefore, 
     %% use erlang:send/3 with the 'noconnect' option so that it 
     %% will fail immediately if there is no connection to the 
     %% remote node. 

     catch erlang:send(Process, {Label, {self(), Mref}, Request}, 
      [noconnect]), 
     receive 
     {Mref, Reply} -> 
      erlang:demonitor(Mref, [flush]), 
      {ok, Reply}; 
     {'DOWN', Mref, _, _, noconnection} -> 
      Node = get_node(Process), 
      exit({nodedown, Node}); 
     {'DOWN', Mref, _, _, Reason} -> 
      exit(Reason) 
     after Timeout -> %% <-- HERE 
      erlang:demonitor(Mref, [flush]), 
      exit(timeout) 
     end 
    catch 
    error:_ -> 
     %% Node (C/Java?) is not supporting the monitor. 
     %% The other possible case -- this node is not distributed 
     %% -- should have been handled earlier. 
     %% Do the best possible with monitor_node/2. 
     %% This code may hang indefinitely if the Process 
     %% does not exist. It is only used for featureweak remote nodes. 
     Node = get_node(Process), 
     monitor_node(Node, true), 
     receive 
     {nodedown, Node} -> 
      monitor_node(Node, false), 
      exit({nodedown, Node}) 
     after 0 -> 
      Tag = make_ref(), 
      Process ! {Label, {self(), Tag}, Request}, 
      wait_resp(Node, Tag, Timeout) %% <-- HERE for C/Java nodes 
     end 
    end.