为什么旧的使用（c ++ 03）auto不能在C ++ 11下编译？ [英] Why old usage (c++03) of auto does not compile under C++11?

问题描述

我知道 auto 之前有一点用处，因为它是变量的默认值（与静态相反） - 参见问题
考虑到有效的C ++ 03代码，其中可能为了不言自明，使用此关键字： / p>

I know that auto has a little usage before because it is the default for variables (opposite to static) - see question Consider however valid C++03 code where, maybe for self-explanatory, this keyword was used:

auto int foo2 = 8;

它在C ++ 03下编译，不能在C ++ 11下编译。
有没有任何理由不回来与C ++ 03兼容？
标准委员会意见的来源是这个关键字没有被使用？有关于关键字使用的统计数据吗？

It compiles under C++03, and does not compile under C++11. Is there any reason for not being back-compatible with C++03? What was the source of standard committee opinion that this keyword was not used? Are there any statistics of keyword usage?

BTW我用gcc测试 - 也许这是一个编译器错误？

BTW i tested with gcc - maybe this is a compiler bug?

推荐答案

已知这会破坏兼容性，并在标准的附录C 2.3第7条中提及。考虑到如何使用无用的汽车，并且确实很容易修复成本被认为是可以接受的。

It was known that this breaks compatibility and is mentioned in Appendix C 2.3 Clause 7 of the standard. Given how useless auto has been and that it is really easy to fix the cost was deemed acceptable.

关于关键字统计：一些有巨大代码基础的公司

As for keyword statistics: Some companies with huge code-bases are on the committee, they probably know if it was acceptable, but I could not dig up any full statistics.

我做了一些标准考古学和最古老的论文，讨论 auto 似乎是N1478，它指的是一个反射器消息的第一次讨论的汽车（所有后来的文章不谈论打破兼容性或推理）。

I did some standards archeology and the oldest paper that talks about auto seems to be N1478, which refers to a reflector message for the first discussing of auto (all later papers don't talk about breaking compatibility or reasoning).

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