我的问题是，如果从析构函数抛出会导致 未定义的行为，如何处理过程中发生的错误 析构函数?

主要的问题是:你不能失败到失败。失败到底意味着什么?如果将事务提交到数据库失败，并且事务未能失败(回滚失败)，那么数据的完整性会发生什么变化?

由于析构函数在正常路径和异常(失败)路径上都被调用，它们本身不能失败，否则我们就是“失败”。

这是一个概念上很困难的问题，但通常解决方案是找到一种方法来确保失败不会失败。例如，数据库可能会在提交到外部数据结构或文件之前写入更改。如果事务失败，则可以丢弃文件/数据结构。它必须确保从外部结构/文件提交的更改是一个不会失败的原子事务。

务实的解决办法也许就是确保 一次又一次的失败在天文学上是不可能的，因为做东西 在某些情况下，失败几乎是不可能的。

对我来说，最合适的解决方案是以一种清理逻辑不会失败的方式编写非清理逻辑。例如，如果您想要创建一个新的数据结构来清理现有的数据结构，那么您可能会寻求提前创建那个辅助结构，这样我们就不必在析构函数中创建它了。

This is all much easier said than done, admittedly, but it's the only really proper way I see to go about it. Sometimes I think there should be an ability to write separate destructor logic for normal execution paths away from exceptional ones, since sometimes destructors feel a little bit like they have double the responsibilities by trying to handle both (an example is scope guards which require explicit dismissal; they wouldn't require this if they could differentiate exceptional destruction paths from non-exceptional ones).

Still the ultimate problem is that we can't fail to fail, and it's a hard conceptual design problem to solve perfectly in all cases. It does get easier if you don't get too wrapped up in complex control structures with tons of teeny objects interacting with each other, and instead model your designs in a slightly bulkier fashion (example: particle system with a destructor to destroy the entire particle system, not a separate non-trivial destructor per particle). When you model your designs at this kind of coarser level, you have less non-trivial destructors to deal with, and can also often afford whatever memory/processing overhead is required to make sure your destructors cannot fail.

And that's one of the easiest solutions naturally is to use destructors less often. In the particle example above, perhaps upon destroying/removing a particle, some things should be done that could fail for whatever reason. In that case, instead of invoking such logic through the particle's dtor which could be executed in an exceptional path, you could instead have it all done by the particle system when it removes a particle. Removing a particle might always be done during a non-exceptional path. If the system is destroyed, maybe it can just purge all particles and not bother with that individual particle removal logic which can fail, while the logic that can fail is only executed during the particle system's normal execution when it's removing one or more particles.

如果避免使用非平凡析构函数处理大量小对象，通常会出现这样的解决方案。当你被大量的小对象纠缠在一起时，你可能会陷入混乱，似乎不可能是异常安全的，这些小对象都有非平凡的dtor。

如果任何指定nothrow/noexcept的函数(包括应该继承其基类的noexcept规范的虚函数)试图调用任何可能抛出的函数，那么nothrow/noexcept实际上会被翻译成编译器错误，这将会有很大帮助。这样我们就能在编译时捕获所有这些东西，如果我们实际上无意中编写了一个析构函数，它可能会抛出。

作为对主要答案的补充，这些答案是好的，全面的和准确的，我想评论一下你引用的文章——那篇文章说“在析构函数中抛出异常并不是那么糟糕”。

本文以“抛出异常的替代方法是什么”为题，并列举了每种替代方法的一些问题。这样做后，它得出结论，因为我们找不到一个没有问题的替代方案，所以我们应该继续抛出异常。

问题在于，它列出的所有问题都没有异常行为那么糟糕，让我们记住，异常行为是“程序的未定义行为”。作者的一些反对意见包括“美学上的丑陋”和“鼓励糟糕的风格”。现在你想要哪一个?一个风格糟糕的程序，还是一个表现出未定义行为的程序?

c++的ISO草案(ISO/IEC JTC 1/SC 22 N 4411)

因此，析构函数通常应该捕获异常，而不是让它们从析构函数传播出去。

为在try块到throw-的路径上构造的自动对象调用析构函数的过程 表达式称为“堆栈unwind”。[注意:如果在堆栈展开期间调用析构函数退出 异常，std::terminate被调用(15.5.1)。因此，析构函数通常应该捕获异常，而不是let 它们从析构函数中传播出去。-结束注]

从析构函数抛出异常永远不会导致未定义的行为。

The problem of throwing exceptions out a destructor is that destructors of successfully created objects which scopes are leaving while handling an uncaught exception (it is after an exception object is created and until completion of a handler of the exception activation), are called by exception handling mechanism; and, If such additional exception from the destructor called while processing the uncaught exception interrupts handling the uncaught exception, it will cause calling std::terminate (the other case when std::exception is called is that an exception is not handled by any handler but this is as for any other function, regardless of whether or not it was a destructor).

如果正在处理未捕获的异常，您的代码永远不知道附加的异常是否会被捕获，或者是否会归档未捕获的异常处理机制，因此永远不知道抛出异常是否安全。

但是，有可能知道正在处理未捕获的异常(https://en.cppreference.com/w/cpp/error/uncaught_exception)，因此可以通过检查条件来过度处理，只在情况不是这样的情况下抛出(在某些情况下它不会抛出，但它是安全的)。

但在实践中，将程序分成两种可能的行为并没有什么用——它只是无助于你设计出一个设计良好的程序。

If you throw out of destructors ignoring whether or not an uncaught exception handling is in progress, in order to avoid possible calling std::terminate, you must guarantee that all exceptions thrown during lifetime of an object that may throw an exception from their destructor are caught before beginning of destruction of the object. It is quite limited usage; you hardly can use all classes which would be reasonably allowed to throw out of their destructor in this way; and a combination of allowing such exceptions only for some classes with such restricted usage of these classes impede making a well-designed program, too.

其他人都解释了为什么抛出析构函数很糟糕……你能做些什么呢?如果您正在执行一个可能失败的操作，请创建一个单独的公共方法来执行清理，并可以抛出任意异常。在大多数情况下，用户会忽略这一点。如果用户希望监视清理的成功/失败，他们可以简单地调用显式清理例程。

例如:

class TempFile {
public:
    TempFile(); // throws if the file couldn't be created
    ~TempFile() throw(); // does nothing if close() was already called; never throws
    void close(); // throws if the file couldn't be deleted (e.g. file is open by another process)
    // the rest of the class omitted...
};

我目前遵循的策略(很多人都这么说)是，类不应该主动从析构函数抛出异常，而是应该提供一个公共的“关闭”方法来执行可能失败的操作……

...but I do believe destructors for container-type classes, like a vector, should not mask exceptions thrown from classes they contain. In this case, I actually use a "free/close" method that calls itself recursively. Yes, I said recursively. There's a method to this madness. Exception propagation relies on there being a stack: If a single exception occurs, then both the remaining destructors will still run and the pending exception will propagate once the routine returns, which is great. If multiple exceptions occur, then (depending on the compiler) either that first exception will propagate or the program will terminate, which is okay. If so many exceptions occur that the recursion overflows the stack then something is seriously wrong, and someone's going to find out about it, which is also okay. Personally, I err on the side of errors blowing up rather than being hidden, secret, and insidious.

关键是容器保持中立，由所包含的类决定它们是否从析构函数抛出异常。