windows -::PostMessage 到一个无效的 hWnd

Question

我有一个线程调用 ::PostMessage(hWnd, [...]); 向主线程发送一条消息，提醒它注意异步操作的结果。

但是，我担心如果线程需要特别长的时间来完成它的操作，当调用 PostMessage 时 hWnd 可能不存在(用户可能已经关闭了窗口)。

MSDN Documentation如果 hWnd 无效，则不会说明任何结果。

如果 hWnd 无效，您是否从经验或其他文档中知道我会发生什么？

Answer 1

Raymond Chen 写道:

• http://blogs.msdn.com/b/oldnewthing/archive/2007/07/16/3885472.aspx
• http://blogs.msdn.com/b/oldnewthing/archive/2007/07/17/3903614.aspx

一些选择摘录:

It so happens that boatloads of programs (and "boatloads" is a technical term) contain bugs where they use window handles after the window has been destroyed. When a window handle is re-used, that program sends a message to the window it thinks is still there, but instead it sends the message to a completely unrelated window. This doesn't bode well for the program, and it usually doesn't bode well for the new window that received the message by mistake either.

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We left off our story last time by raising the problem of programs that send messages to windows that have already been destroyed and how window handle re-use exacerbates the problem. Although this is clearly a bug in the programs that use window handles after destroying the window, the problem is so widespread that the window manager folks in Windows NT decided to take a more proactive approach.