LNK2001& LNK1120 在项目中包含 DLL 时 - MSVC++

发布于 2025-01-01 13:17:02 字数 669 浏览 0 评论 0原文

我有一个 DLL 和 lib 文件。我已将它们包含在根源目录中，并通过其他依赖项添加了 lib 引用。但是，我收到以下错误：

1>main.obj : error LNK2001: unresolved external symbol "class game::c_State game::state" (?state@game@@3Vc_State@1@A)
fatal error LNK1120: 1 unresolved externals

which would bereferencing this from "engine.h":

extern __declspec(dllexport) c_State state;

In "state.cpp"（来自 DLL 的源代码），它被声明为

namespace game
{
    c_State state;
    //clipped for relevance
}

难道我需要将 DLL 放置在特定的地方？ Windows 知道去哪里查找吗？我在属性中没有找到专门引用 DLL 文件的地方，只有 lib 文件。

另外，在声明变量或仅声明函数时是否需要 __declspec(dllexport) ？

提前致谢！

原文

I have a DLL and lib file. I've included them in the root source directory and added the lib reference through Additional Dependencies. However, I get the following error:

1>main.obj : error LNK2001: unresolved external symbol "class game::c_State game::state" (?state@game@@3Vc_State@1@A)
fatal error LNK1120: 1 unresolved externals

which would be referencing this from "engine.h":

extern __declspec(dllexport) c_State state;

In "state.cpp" (from the DLL's source,) it is declared as

namespace game
{
    c_State state;
    //clipped for relevance
}

Could it be that I need to place the DLL somewhere specific? Does Windows know where to look? I found nowhere in the properties to specifically reference the DLL file, only the lib file.

Also, do I need a __declspec(dllexport) when declaring variables, or only functions?

Thanks in advance!

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野味少女 2025-01-08 13:17:02

您必须将 __declspec(dllexport) 应用于定义，而不是声明。此外，该声明需要其他项目中的 __declspec(dllimport) 。因此在 .h 文件中：

#undef EXPORT
#ifdef FOO_EXPORTS
#  define EXPORT __declspec(dllexport)
#else
#  define EXPORT __declspec(dllimport)
#endif

extern EXPORT int shared;

在 DLL 源代码文件中：

__declspec(dllexport) int shared;

在 DLL 项目中使用 Project + Properties、C/C++、Proprocessor。将 FOO_EXPORTS 添加到预处理器定义中。

You have to apply __declspec(dllexport) to the definition, not the declaration. Also, the declaration needs __declspec(dllimport) in the other project. So in the .h file:

#undef EXPORT
#ifdef FOO_EXPORTS
#  define EXPORT __declspec(dllexport)
#else
#  define EXPORT __declspec(dllimport)
#endif

extern EXPORT int shared;

In the DLL source code file: