在不同的过程中，使用DuplicateHandle(...)函数如何共享一个句柄? [英] In the process of different, use DuplicateHandle(...) function how to share a handle?

问题描述

例如:

g_hComm = CreateFile ("COM1",GENERIC_READ | GENERIC_WRITE, 0, 0, NULL, OPEN_EXISTING, NULL);

如何将g_hComm 此句柄与其他使用的进程共享?

我是新手，请尝试举例.谢谢！

How to put the g_hComm this handle Shared with other process used?

I am a novice, try to give examples. thank you!

推荐答案

首先，如果您是新手，我建议您避免在进程之间共享文件以及避免重复使用任何句柄:1)这些相关技术不是很容易理解； 2)它们不安全； 3)这不是推荐的做法；建议的做法应保持流程的主要特征-它们之间的强隔离，而打破这种隔离是一个有问题的做法.如果有的话，它可能会用在一些真正罕见且复杂的技术中.

现在，我看不到所获得的手柄重复的用途是什么，因为-您将如何使用它?问题是您调用CreateFile，dwShareMode == 0的第三个参数.如果您不共享文件，如何使用该句柄的副本?您需要使用FILE_SHARE_READ或FILE_SHARE_WRITE或FILE_SHARE_READ | FILE_SHARE_WRITE.阅读，所有内容均已说明:
http://msdn.microsoft.com/zh-我们/library/windows/desktop/aa363858%28v=vs.85%29.aspx [ http://msdn.microsoft.com/zh-我们/library/windows/desktop/ms724251%28v=vs.85%29.aspx [

First of all, if you are a novice, I would recommend you to avoid sharing files between processes and duplication of any handles: 1) these related techniques are not very easy for understanding; 2) they are unsafe; 3) this is not a recommended practice; a recommended practices should maintain main feature of the processes — strong isolation between them, and breaking through this isolation is a questionable practice. It can be used probably in some really rare and sophisticated technology, if any.

Now, I don''t see what could be the use of duplication of the handle you have obtained, because — how would you use it? The problem is the third parameter of your call to CreateFile, dwShareMode == 0. How can you use the handle''s duplicate if you are not sharing the file? You need to use FILE_SHARE_READ, or FILE_SHARE_WRITE or, say, FILE_SHARE_READ | FILE_SHARE_WRITE. Read, everything is explained:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa363858%28v=vs.85%29.aspx[^].

And them you can share the handler, either in this or a foreign process. You need to pass the original handle and a handle to a different process or obtain a handle of a foreign process, use it to duplicate a handle and pass a handle duplicate back to a foreign process. Everything is explained:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms724251%28v=vs.85%29.aspx[^].

Now, how to communicate between processes is your problem, a separate one. This is called Inter-Process Communication (IPC). You just need to learn about it; this is a separate big topic. You can use sockets, named pipes, shared memory and so on.

Before going into all of that, please re-read my first paragraph above and think is you really need it. Also, when asking questions, it''s the best to start with explaining your purpose and your ultimate goals.

—SA

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