如何检查文件是否已经被用C另一个进程打开？ [英] How to check if a file is already open by another process in C?

问题描述

我看到，标准C没有如果文件在另一个进程已经打开，告诉的方式。所以答案应包含每个平台的几个例子。我需要检查的Visual C ++ / Windows的虽然。

I see that standard C has no way of telling if a file is already opened in another process. So the answer should contain several examples for each platform. I need that check for Visual C++ / Windows though.

推荐答案

有没有办法分辨，除非其他进程明确禁止对文件的访问。在MSVC，你会用 _fsopen这样做（），指定 _SH_DENYRD 为shflag说法。有兴趣来一个文件是否被打开未上锁，否则这个概念是一个多任务操作系统上存在严重缺陷。它可能被打开微秒后，你会发现它不是。这也是Windows不具有IsFileLocked（）函数的原因。

There's no way tell, unless the other process explicitly forbids access to the file. In MSVC, you'd do so with _fsopen(), specifying _SH_DENYRD for the shflag argument. The notion of being interested whether a file is opened that isn't otherwise locked is deeply flawed on a multitasking operating system. It might be opened a microsecond after you'd have found it wasn't. That's also the reason that Windows doesn't have a IsFileLocked() function.

如果您需要将文件同步访问，你需要用一个命名互斥添加此，使用CreateMutex（）。

If you need synchronized access to files, you'll need to add this with a named mutex, use CreateMutex().

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