C ++错误代码vs ASSERTS VS异常选择选择:( [英] C++ error-codes vs ASSERTS vs Exceptions choices choices :(
问题描述
我听说过（反感）了栅栏两边的C ++异常咒语。这已经有一段时间了，我只是想再次集中自己，这个讨论特定于我链接的代码（或低级类，如容器），它的依赖。我以前是一个防御和error_code使用C程序员，但它是一个令人讨厌的做法，我现在在更高的抽象层次编程。
I have heard (and regurgitated) the C++ exception mantra on both sides of the fence. It has been a while and I just want to centre myself once more, and this discussion is specific to the code I have linked (or low level classes such as containers), and it's dependencies. I used to be a defensive and error_code using C programmer, but it's a tiresome practise and I am programming at a higher level of abstraction now.
所以我重写一个容器类（和它的依赖）更灵活和阅读更好（迭代器缺席atm）。正如你可以看到我回传枚举的error_codes，我知道我会在call-site测试他们。这些容器用于运行时构建AST，初始化和只读。例外是他们防止容器被天真地使用（可能由未来自己使用）。
So I am rewriting a container class (and it's dependencies) to be more flexible and read better (iterators absent atm). As you can see I am returning enumerated error_codes where I know I will test them at call-site. The containers are for runtime building of AST's, initialize and make read-only. The exceptions are their to prevent the container being used naively (possibly by myself in the future).
我在这个课程的地方有例外，他们让我感觉很脏。我欣赏他们的用例。如果我有选择，我可以把他们完全（Boost使用例外很多，我建立Boost，是的，我知道他们可以被禁用，但在罗马....）。我有选择替换他们与error_codes，但嘿，我不会测试他们，所以是什么点？
I have exceptions all over the place in this class, and they make me feel dirty. I appreciate their use-case. If I had the choice I might turn them off altogether (Boost uses exceptions a lot, and I am building off Boost, and yes I know they can be disabled, but when in Rome....) . I have the choice of replacing them with error_codes but hey, I will not test them , so what is the point ?
我应该用ASSERTS替换它们吗？这是什么人膨胀的人说出来 [1] [2] [3] ？每个功能callsite是否获得额外的机械？或只有那些有catch子句？因为我不会抓住这些例外，我不应该成为这种膨胀权的受害者？ ASSERTS不会进入发布版本，在基本的原始类（即容器）的上下文中，甚至是重要的吗？我的意思是，逻辑错误会进入最终构建的机会有多高？
Should I replace them with ASSERTS ? What is this bloat people speak off [1] [2] [3]? does every function callsite get extra machinery ? or only those that have a catch clause ? Since I won't catch these exceptions I shouldn't be a victim of this bloatage right ? ASSERTS do not make their way into release builds, in the context of fundamental primitive classes ( -- i.e, containers) does that even matter ? I mean how high are the chances that logic errors would find their way into a final build ?
由于我们想回答重点突出的问题，这里是我的：您会做什么，为什么？：D
Since we like to answer focused questions, here is mine: What would you do, and why ? :D
Unrelated Link:Error codes and having them piggy backing in an exception.
编辑2 在此特定的错误代码中出现错误代码，例如：hrel =nofollow case选择是在ASSERT和异常之间，我认为异常最有意义，如上所述，容器只在初始化后读取，大多数异常在初始化时触发。
edit 2 in this particular case the choice is between ASSERTs and exceptions, I think exceptions make the most sense, as I mentioned above, the container is read only after initialisation, and most of the exceptions are triggered during initialisation.
推荐答案
这很简单。避免错误代码，如火和喜欢异常，除非错误代码真的在某种情况下更有意义。为什么？因为异常可以携带更多的信息 - 参见例如。 Boost.Exception。因为它们会自动传播，因此您不能错误地 检查错误情况。因为有时候，你到（从一个构造函数中），所以为什么不一致。 C ++根本不提供任何更好的信号错误条件的方法。
It's very simple. Avoid error codes like fire and prefer exceptions, unless error code really makes more sense in an individual case. Why? Because exceptions can carry a lot more information — see e.g. Boost.Exception. Because they propagate automatically, so you can't make a mistake of not checking for error condition. Because sometimes, you have to (bailing out of a constructor), so why not be consistent. C++ simply does not offer any better way for signalling error conditions.
另一方面，Asserts用于完全不同的东西 - 验证代码的内部状态，假设应该总是成立。
Asserts, on the other hand, are used for something completely different — verifying internal state of the code, and assumptions that should always hold true. Failed assertion is always a bug — whereas exception might signal invalid external input, for example.
对于链接的指南：忘记Google风格指南甚至存在，它是可怕的，而且这不只是我的意见。 LLVM - 可执行的大小几乎不重要，它不是真的你应该浪费时间思考。 Qt - Qt缺乏异常安全，但这并不意味着你的代码也。使用现代做法，并且安全的例外不应太难。
As for linked guides: forget Google style guide even exists, it's simply terrible, and it's not just my opinion. LLVM — executable size hardly matters, it's not really something you should waste time thinking about. Qt — Qt is lacking in exception safety, but that doesn't mean your code has to, too. Use modern practices, and being exception safe shouldn't be too hard.
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