为什么动态检查C ++ 0x的“noexcept”？ [英] Why is C++0x's `noexcept` checked dynamically?

问题描述

我很好奇 noexcept 背后的理由/papers/2010/n3092.pdfrel =noreferrer> C ++ 0x FCD 。 throw（X）已被弃用，但 noexcept 似乎也做同样的事情。有没有理由在编译时没有检查 noexcept ？似乎这样做会更好，如果这些功能被静态地检查，他们只是在 try 块中调用抛出函数。

I am curious about the rationale behind noexcept in the C++0x FCD. throw(X) was deprecated, but noexcept seems to do the same thing. Is there a reason that noexcept isn't checked at compile time? It seems that it would be better if these functions were checked statically that they only called throwing functions within a try block.

推荐答案

如果我记得throw已被弃用，因为没有办法指定模板函数可以抛出的所有异常。即使对于非模板函数，您将需要使用throw子句，因为您添加了一些跟踪。

If I remember throw has been deprecated because there is no way to specify all the exceptions a template function can throw. Even for non-template functions you will need the throw clause because you have added some traces.

另一方面，编译器可以优化不抛出异常的代码。请参阅第一部分noexcept辩论（以及 II 和 III ）进行详细的讨论。主要观点似乎是：

On the other hand the compiler can optimize code that doesn't throw exceptions. See "The Debate on noexcept, Part I" (along with parts II and III) for a detailed discussion. The main point seems to be:

过去二十年的丰富经验表明，在实践中，只有两种形式的异常规范是有用的：

The vast experience of the last two decades shows that in practice, only two forms of exceptions specifications are useful:

• 缺少一个公开异常规范，指定一个可以引发任何类型异常的函数：

• The lack of an overt exception specification, which designates a function that can throw any type of exception:

int func(); //might throw any exception

永远不会抛出的函数。这样一个函数可以通过throw（）指定：

A function that never throws. Such a function can be indicated by a throw() specification:

int add(int, int) throw(); //should never throw any exception

这篇关于为什么动态检查C ++ 0x的“noexcept”？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！