C ++静态初始化顺序惨败 [英] c++ static initialization order fiasco

问题描述

我目前正在学习C ++，但遇到了一些麻烦.

I'm currently learning C++, and I'm having some troubles.

我已经通过使用许多 #define 开发了一个程序，但是我想改用 static const (碰撞/类型/作用域...)

I've developped a program by using lots of #define, but I'd like to use static const instead (collision/type/scopes...).

所以，我现在有类似的东西:

So, I now have something like:

file1.hpp

 class A {
   public:
     static const std::string MY_CONST_VAR;
 };

file1.cpp

 const std::string A::MY_CONST_VAR = "some string";

file2.cpp

 static std::string arrayOfString[] = {
   A::MY_CONST_VAR,
   ...
  };

我的代码编译时没有警告/错误(使用-W -Wall -Wextra -Werror标志进行编译).

My code compiles with no warnings/errors (compiling with -W -Wall -Wextra -Werror flags).

但是，当我尝试运行它时，会导致段错误.

However, when I try to run it, it results in a segfault.

我已经用valgrind来运行它，它给了我以下输出:

I've ran it with valgrind, and it gave me the following ouput:

==11239== Invalid read of size 4
==11239==    at 0x5F525CB: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::string const&) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.19)
==11239==    by 0x40D076: _GLOBAL__sub_I__ZN16GraphicInterface13DEFAULT_WIDTHE (GraphicInterface.cpp:42)
==11239==    by 0x51AC7C: __libc_csu_init (in /home/simon/PSU_2013_zappy/gui/gui_zappy)
==11239==    by 0x66D8E54: (below main) (libc-start.c:246)
==11239==  Address 0xfffffffffffffff8 is not stack'd, malloc'd or (recently) free'd

因此，segfault发生在arrayOfString实例化期间.我认为问题在于arrayOfInt在常量之前分配.但是在那种情况下，是否可以为此目的使用静态const?

So, the segfault occurs during the arrayOfString instanciation. I think the problem is that the arrayOfInt is allocated before the constant. But in that case, is it possible to use static const for this purpose?

我不知道如何解决此问题.我做错了吗?有更好的方法吗?如何解决这个问题?

I don't know how to patch this issue. Am I doing it wrong? Is there a better way to do it? How to solve this issue?

推荐答案

多亏了这些注释，我终于通过使用 constexpr 关键字解决了这个问题.

Thanks to the comments, I finally solved the problem by using constexpr keyword.

它为我提供了以下工作代码:

It gives me the following working code:

file1.hpp

class A {
  public:
    static constexpr char MY_CONST_VAR[] = "some string";
};

file1.cpp

const char A::MY_CONST_VAR[];

file2.cpp

static std::string arrayOfString[] = {
  A::MY_CONST_VAR,
  ...
};

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