如何终止匿名线程在Delphi中的应用程序关闭？ [英] How to terminate anonymous threads in Delphi on application close?

问题描述

我有一个Delphi应用程序，在一些TTimer.OnTimer事件上产生6个匿名线程。

如果我从标题栏中的X按钮关闭应用程序访问违例地址$ C0000005被提升，并且FastMM报告泄漏了TAnonymousThread对象。

哪些是使用TThread.CreateAnonymousThread（）方法在OnTimer事件中创建的Delphi中释放匿名线程的最佳方式？ / p>

解决方案对我有用：

创建一个匿名线程的包装器，在被释放时终止它们

  type 
 TAnonumousThreadPool = class sealed（TObject）
 strict private 
 FThreadList：TThreadList ; 
程序TerminateRunningThreads; 
 procedure AnonumousThreadTerminate（Sender：TObject）; 
 public 
析构函数Destroy;覆盖最后; 
程序启动（const Procs：TProc数组）; 
结束
 
 {TAnonumousThreadPool} 
 
程序TAnonumousThreadPool.Start（const Procs：TProc数组）; 
 var 
 T：TThread 
 n：整数; 
 begin 
 TerminateRunningThreads; 
 
 FThreadList：= TThreadList.Create; 
 FThreadList.Duplicates：= TDuplicates.dupError; 
 
为n：=低（Procs）到高（Procs）do 
 begin 
 T：= TThread.CreateAnonymousThread（Procs [n]）; 
 TThread.NameThreadForDebugging（AnsiString（'Test thread N：'+ IntToStr（n）+'TID：'），T.ThreadID）; 
 T.OnTerminate：= AnonumousThreadTerminate; 
 T.FreeOnTerminate：= true; 
 FThreadList.LockList; 
 try 
 FThreadList.Add（T）; 
 finally 
 FThreadList.UnlockList; 
结束
 T.Start; 
结束
结束
 
 procedure TAnonumousThreadPool.AnonumousThreadTerminate（Sender：TObject）; 
 begin 
 FThreadList.LockList; 
 try 
 FThreadList.Remove（（Sender as TThread））; 
 finally 
 FThreadList.UnlockList; 
结束
结束
 
程序TAnonumousThreadPool.TerminateRunningThreads; 
 var 
 L：TList; 
 T：TThread; 
 begin 
如果没有分配（FThreadList）然后
退出; 
 L：= FThreadList.LockList; 
尝试
，而L.Count> 0 do 
 begin 
 T：= TThread（L [0]）; 
 T.OnTerminate：= nil; 
 L.Remove（L [0]）; 
 T.FreeOnTerminate：= False; 
 T.Terminate; 
 T.Free; 
结束
 finally 
 FThreadList.UnlockList; 
结束
 FThreadList.Free; 
结束
 
析构函数TAnonumousThreadPool.Destroy; 
 begin 
 TerminateRunningThreads; 
继承; 
结束
  

结束这里是如何调用它：

  procedure TForm1.Button1Click（Sender：TObject）; 
 begin 
 FAnonymousThreadPool.Start（[//要执行的程序数组
 procedure {anonymous1}（）
 var 
 Http：THttpClient; 
 begin 
 Http：= THttpClient.Create; 
 try 
 Http.CancelledCallback：= function：Boolean 
 begin 
结果：= TThread.CurrentThread.CheckTerminated; 
 end ; 
 Http.GetFile（'http://mtgstudio.com/Screenshots/shot1.png'，'c：\1.jpg'）; 
 finally 
 Http.Free; 
 end; 
 end，
 
 procedure {anonymous2}（）
 var 
 Http：THttpClient; 
 begin 
 Http：= THttpClient.Create; 
 try 
 Http.CancelledCallback：= function：Boolean 
 begin 
结果：= TThread.CurrentThread.CheckTerminated; 
 end; 
 Http .GetFile（'http://mtgstudio.com/Screenshots/shot2.png'，'c：\2.jpg'）; 
 finally 
 Http.Free; 
 end; 
结束
]）; 
结束
  

没有内存泄漏，正常关机和易于使用。

解决方案

如果要维护并对线程的生命周期进行控制，则必须将 FreeOnTerminate 设置为 False 。否则，在线程开始执行后引用线程是一个错误。这是因为一旦它开始执行，你没有准备好的方法来知道它是否被释放。

调用 CreateAnonymousThread 创建一个 FreeOnTerminate 设置为 True 。

线程也被标记为FreeOnTerminate，所以在调用Start后不应该触摸返回的实例。

所以，但默认情况下，你无法对线程的生命周期进行控制。但是，您可以在调用开始之前将 FreeOnTerminate 设置为 False 开始。像这样：

  MyThread：= TThread.CreateAnonymousThread（MyProc）; 
 MyThread.FreeOnTerminate：= False; 
 MyThread.Start; 
  

但是，我不知道我会这样做。 CreateAnonymousThread 的设计是线程在终止后自动释放。我想我个人会按照预期的设计，或者派生我自己的 TThread descendent。

I have a Delphi application which spawns 6 anonymous threads upon some TTimer.OnTimer event.

If I close the application from the X button in titlebar Access Violation at address $C0000005 is raised and FastMM reports leaked TAnonymousThread objects.

Which is the best way to free anonymous threads in Delphi created within OnTimer event with TThread.CreateAnonymousThread() method?

SOLUTION which worked for me:

Created a wrapper of the anonymous threads which terminates them upon being Free-ed.

type
  TAnonumousThreadPool = class sealed(TObject)
  strict private
    FThreadList: TThreadList;
    procedure TerminateRunningThreads;
    procedure AnonumousThreadTerminate(Sender: TObject);
  public
    destructor Destroy; override; final;
    procedure Start(const Procs: array of TProc);
  end;

{ TAnonumousThreadPool }

procedure TAnonumousThreadPool.Start(const Procs: array of TProc);
var
  T: TThread;
  n: Integer;
begin
  TerminateRunningThreads;

  FThreadList := TThreadList.Create;
  FThreadList.Duplicates := TDuplicates.dupError;

  for n := Low(Procs) to High(Procs) do
  begin
    T := TThread.CreateAnonymousThread(Procs[n]);
    TThread.NameThreadForDebugging(AnsiString('Test thread N:' + IntToStr(n) + ' TID:'), T.ThreadID);
    T.OnTerminate := AnonumousThreadTerminate;
    T.FreeOnTerminate := true;
    FThreadList.LockList;
    try
      FThreadList.Add(T);
    finally
      FThreadList.UnlockList;
    end;
    T.Start;
  end;
end;

procedure TAnonumousThreadPool.AnonumousThreadTerminate(Sender: TObject);
begin
  FThreadList.LockList;
  try
    FThreadList.Remove((Sender as TThread));
  finally
    FThreadList.UnlockList;
  end;
end;

procedure TAnonumousThreadPool.TerminateRunningThreads;
var
  L: TList;
  T: TThread;
begin
  if not Assigned(FThreadList) then
    Exit;
  L := FThreadList.LockList;
  try
    while L.Count > 0 do
    begin
      T := TThread(L[0]);
      T.OnTerminate := nil;
      L.Remove(L[0]);
      T.FreeOnTerminate := False;
      T.Terminate;
      T.Free;
    end;
  finally
    FThreadList.UnlockList;
  end;
  FThreadList.Free;
end;

destructor TAnonumousThreadPool.Destroy;
begin
  TerminateRunningThreads;
  inherited;
end;

End here is how you can call it:

procedure TForm1.Button1Click(Sender: TObject);
begin
  FAnonymousThreadPool.Start([ // array of procedures to execute
    procedure{anonymous1}()
    var
      Http: THttpClient;
    begin
      Http := THttpClient.Create;
      try
        Http.CancelledCallback := function: Boolean
          begin
            Result := TThread.CurrentThread.CheckTerminated;
          end;
        Http.GetFile('http://mtgstudio.com/Screenshots/shot1.png', 'c:\1.jpg');
      finally
        Http.Free;
      end;
    end,

    procedure{anonymous2}()
    var
      Http: THttpClient;
    begin
      Http := THttpClient.Create;
      try
        Http.CancelledCallback := function: Boolean
          begin
            Result := TThread.CurrentThread.CheckTerminated;
          end;
        Http.GetFile('http://mtgstudio.com/Screenshots/shot2.png', 'c:\2.jpg');
      finally
        Http.Free;
      end;
    end
  ]);
end;

No memory leaks, proper shutdown and easy to use.

解决方案

If you want to maintain and exert control over a thread's lifetimes then it must have FreeOnTerminate set to False. Otherwise it is an error to refer to the thread after it has started executing. That's because once it starts executing, you've no ready way to know whether or not it has been freed.

The call to CreateAnonymousThread creates a thread with FreeOnTerminate set to True.

The thread is also marked as FreeOnTerminate, so you should not touch the returned instance after calling Start.

And so, but default, you are in no position to exert control over the thread's lifetime. However, you could set FreeOnTerminate to False immediately before calling Start. Like this:

MyThread := TThread.CreateAnonymousThread(MyProc);
MyThread.FreeOnTerminate := False;
MyThread.Start;

However, I'm not sure I would do that. The design of CreateAnonymousThread is that the thread is automatically freed upon termination. I think I personally would either follow the intended design, or derive my own TThread descendent.

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