C++，我可以在编译时静态初始化 std::map 吗?

C++, can I statically initialize a std::map at compile time?(C++，我可以在编译时静态初始化 std::map 吗?)

问题描述

如果我编码这个

std::map<int, char> example = {
                                (1, 'a'),
                                (2, 'b'),
                                (3, 'c') 
                              };

然后g++对我说

deducing from brace-enclosed initializer list requires #include <initializer_list>
in C++98 ‘example’ must be initialized by constructor, not by ‘{...}’   

这让我有点恼火，因为构造函数是运行时的，理论上可能会失败.

and that annoys me slightly because the constructor is run-time and can, theoretically fail.

当然，如果确实如此，它会很快失败并且应该始终如一地这样做，因此我应该快速定位 &纠正问题.

Sure, if it does, it will fail quickly and ought to do so consistently, so that I ought to quickly locate & correct the problem.

但是，我仍然很好奇 - 有没有在编译时初始化地图、向量等?

But, still, I am curious - is there anyway to initialize map, vector, etc, at compile time?

我应该说我正在为嵌入式系统开发.并非所有处理器都有 C++0x 编译器.最流行的可能会，但我不想遇到陷阱&必须维护 2 个版本的代码.

I should have said that I am developing for embedded systems. Not all processors will have a C++0x compiler. The most popular probably will, but I don't want to encounter a gotcha & have to maintain 2 versions of the code.

至于 Boost，我还没有决定.他们对在嵌入式系统中使用他们的有限状态机类是一厢情愿的，所以这实际上是我在这里编码的，事件/状态/Fsm 类.

As to Boost, I am undecided. They are wishy-washy on the use of their Finite State Machine classes in embedded systems, so that is actually what I am coding here, Event/State/Fsm classes.

唉，我想我还是谨慎一点为好，但我希望这个讨论对其他人有所帮助.

Sigh, I guess I'd better just play it safe, but I hope that this discussion has been helpful for others.

推荐答案

不在 C++98 中.C++11 支持这一点，因此如果您启用 C++11 标志并包含 g++ 建议的内容，则可以.

Not in C++98. C++11 supports this, so if you enable C++11 flags and include what g++ suggests, you can.

从 gcc 5 C++11 默认开启

from gcc 5 C++11 is on by default

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