使非对象资源符合RAII [英] Making a non-object resource RAII-compliant

问题描述

在我的代码中，我使用了windows.h中的HANDLE.它们的用法就像

in my code I use HANDLEs from windows.h. They are used like

HANDLE h;
if (!openHandleToSomething(arg1, arg2, &h)) {
    throw std::exception("openHandleToSomething error");
}
/* Use the handle in other functions which can throw as well */
if (!CloseHandle(h)) {
    throw std::exception("closeHandle error");
}

如您所见，您必须将此CloseHandle插入到在获取和发布过程中可能发生的每个异常.因此，很可能您忘记了一个(或者有一个您不知道的奇特的SEH异常)，然后发现内存泄漏.

As you see, you have to insert this CloseHandle to every exception which can happen in the middle of acquiration and release. Therefore, it's likely you forget one (or there is a fancy SEH exception which you didn't know about) and voilà, you have your memory leak.

最近，我读到有关RAII的信息，它应该可以消除此类情况下的头痛，并应自动将其称为CloseHandle.我还看到C ++中有类似std::auto_ptr<someType>的东西可以解决使用new分配的资源的问题.

Recently, I've read about RAII which should remove the headaches from such cases and should call this CloseHandle automatically. I've also seen that there is something like std::auto_ptr<someType> in C++ which solves the problem for resources which were allocated with new.

但是，由于我不使用new，并且由于HANDLE只是被typedef修改为void *，所以我想知道如何使用std::auto_ptr<someType>.以某种方式，应该有可能为其提供自定义删除器功能(if (!CloseHandle(h)) { throw std::exception("closeHandle error"); }).创建类将是另一种方法，因为只要析构函数的实例超出范围，就会调用该析构函数.但是，为每一个简单的事情都上一堂课是太过分了.

However, since I don't use new and since HANDLE is just typedefed to be a void *, I wonder how I should use the std::auto_ptr<someType>. Somehow, it should be possible to give it a custom deleter function (if (!CloseHandle(h)) { throw std::exception("closeHandle error"); }). Creating a class would be another method since the destructor gets called any time an instance of it gets out of scope. However, it's just overkill to have a class for every simple thing.

如何解决这些意外的内存泄漏?

How can I fix these accidential memory leaks?

请注意，我更喜欢纯C ++，无库且无大依赖项的解决方案，除非它们确实很小，并且无论如何都在大多数环境中使用.

Note that I would prefer solutions which are in pure C++ with no libraries and big dependencies except if they are really small and used in most of the environments anyways.

推荐答案

想到的一个想法是使用

One idea that comes to mind is to use boost::shared_ptr with a custom deleter.

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