extern const char* const SOME_CONSTANT 给我链接器错误

extern const char* const SOME_CONSTANT giving me linker errors(extern const char* const SOME_CONSTANT 给我链接器错误)

问题描述

我想在 API 中提供一个字符串常量，如下所示:

I want to provide a string constant in an API like so:

extern const char* const SOME_CONSTANT;

但如果我在我的静态库源文件中将其定义为

But if I define it in my static library source file as

const char* const SOME_CONSTANT = "test";

我在链接到该库并使用 SOME_CONSTANT 时遇到链接器错误:

I'm getting linker errors when linking against that library and using SOME_CONSTANT:

错误 1 ​​错误 LNK2001:无法解析的外部符号char const * const SOME_CONSTANT"(?SOME_CONSTANT@@3QBDB)

Error 1 error LNK2001: unresolved external symbol "char const * const SOME_CONSTANT" (?SOME_CONSTANT@@3QBDB)

从 extern const char* const 声明和定义中删除指针 const-ness(第二个 const 关键字)使其工作.如何使用指针常量导出它?

Removing the pointer const-ness (second const keyword) from both the extern const char* const declaration and the definition makes it work. How can I export it with pointer const-ness?

推荐答案

问题可能是 extern 声明在定义常量的源文件中不可见.尝试重复定义上面的声明，如下所示:

The problem could be that the extern declaration is not visible in the source file defining the constant. Try repeating the declaration above the definition, like this:

extern const char* const SOME_CONSTANT;  //make sure name has external linkage
const char* const SOME_CONSTANT = "test";  //define the constant

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