线程中的奇怪问题，应用程序无法退出 [英] Strange problem in threads, application doesn't exit

问题描述

好的，我正在编写一个Zoom组件，并且希望它从辅助线程的屏幕上捕获。
您可以假装我只想在一个空组件中派生TThread。我没有在线程中编写任何代码，所以它只是一个简单的无用线程。我编写了这段代码： Thrd：= TCaptureThread.Create（False）; 在组件主类中。
然后我在主类销毁代码中编写了 Thrd.Free 。现在，当我关闭整个应用程序时，尽管它破坏了所有内容，但该过程并未完全终止。在Windows中，任务管理器显示线程数为1，但进程仍然存在。如果我在线程创建行中添加注释，则一切正常，应用程序快速终止。我要怎么办？ ：（

OK I'm writing a Zoom component and I wanted it to capture from screen within a secondary thread. You can pretend I just want to derive TThread in an empty component. I didn't write any codes in the thread so it is just a simple useless thread. I wrote this code: Thrd := TCaptureThread.Create(False); in the component main class. Then I wrote Thrd.Free in the main class destruction code. Now when I close the whole application, although it destroys everything, the process doesn't terminate completely. In Windows Task Manager shows that number of threads is 1 but the process remains. If I comment the thread creation line, everything becomes OK and application terminates quickly. What am I gonna do about this? :(

预先感谢

推荐答案

当您致电 Thrd.Free 运行来自 TThread.Destroy 的以下代码：

When you call Thrd.Free the following code from TThread.Destroy is run:

Terminate;
if FCreateSuspended then
  Resume;
WaitFor;

在线程上调用 Free 将因此同步终止线程。

Calling Free on a thread will thus terminate the thread synchronously.

我的猜测是对 WaitFor 的调用永远不会返回。也许 TCaptureThread.Execute 不会检查已终止并退出，也许 TCaptureThread 正在等待主线程，因此等待线程死锁。

My guess is that the call to WaitFor never returns. Perhaps TCaptureThread.Execute doesn't check Terminated and exit. Perhaps TCaptureThread is waiting on the main thread and so the wait on the thread deadlocks.

根据您的问题，除了猜测外，很难做其他任何事情，但是我想检查您的代码是否超过了 WaitFor 调用销毁 Thrd 启用调试DCU，将一个断点设置为对 WaitFor 的调用你自己。

It's pretty hard to do anything other than guess, based on your question, but I'd want to check whether or not your code gets past the WaitFor call in the destruction of Thrd. Enable Debug DCUs, set a breakpoint one the call to WaitFor and see for yourself.

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