对于lambda表达式，noexcept和空抛出规范之间有什么区别吗?

问题描述：

举个例子:

double values[] {2.5, -3.5, 4.5, -5.5, 6.5, -7.5};
std::vector<double> squares(std::end(values) - std::begin(values));

std::transform(std::begin(values), std::end(values), std::begin(values), std::begin(squares),
    [](double x1, double x2) throw() { return x1 * x2; });

这在功能上等同于以下内容吗?

Is this functionally equivalent to the following?

[](double x1, double x2) noexcept { return x1 * x2; })

是否有令人信服的原因，为什么我应该用修饰符标记这样的表达式(或类似的基本表达式)，或者在这种情况下，最好不要使用它，而只是不要打扰?

Is there a convincible reason, why should I mark such expression (or similar basic expresions) with either modifiers or in this case, it is better to leave it and simply don't bother?

答

noexcept和空抛出规范之间是否有任何区别...?

Is there any difference between noexcept and empty throw specification...?

是的.

想到的第一个区别是，如果引发异常，会发生什么?

The first difference that comes to mind is what happens if an exception is thrown?

对于throw()，将调用std::unexpected() . unexpected的默认处理程序将调用terminate.
对于noexcept，将调用 std::terminate() .

In the case of throw(), std::unexpected() is called. The default handler for unexpected will call terminate.
In the case of noexcept, std::terminate() is called.

第二个是动态异常规范已弃用.

The second is that the dynamic exception specification is deprecated.

弃用

noexcept 是throw()的改进版本，在C ++ 11中已弃用.与throw()不同， noexcept 不会调用std::unexpected，并且可能会也可能不会取消堆栈，这可能使编译器无需运行时即可实现 noexcept throw()的开销.

noexcept is an improved version of throw(), which is deprecated in C++11. Unlike throw(), noexcept will not call std::unexpected and may or may not unwind the stack, which potentially allows the compiler to implement noexcept without the runtime overhead of throw().

是否有令人信服的理由，为什么我要用任一修饰符标记这样的表达式(或类似的基本表达式)??

Is there a convincible reason, why should I mark such expression (or similar basic expresions) with either modifiers...?

这是一种意图的表达.如果您打算不让lambda抛出，并且认为这样做对程序执行具有致命性，那么可以-您应将lambda标记为noexcept(不推荐使用throw()).

It is an expression of intent. If you intend that the lambda never throws, and if it does it is deemed fatal to the execution of the program, then yes - you should mark the lambda as noexcept (throw() is deprecated).

对于lambda表达式，noexcept和空抛出规范之间有什么区别吗?

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