Visual Studio 2013 dll导出联动错误（LNK2019 / LNK1120） [英] Visual Studio 2013 dll export linkage error (LNK2019/LNK1120)

问题描述

我知道类似的问题之前已经被问过了，但是看起来像在一些简单的函数中有什么不同的类导出的东西...我已经检查了所有这些解决方案，检查所有的建议，但仍然看起来像我缺少一些东西...

发生了什么：

• 我有一个主C ++在Visual Studio 2013中编写的项目，我想添加一个带有各种实用程序的dll库。我创建了一个虚拟的，基本上没有功能，但是它无法编译：

 
 2> TestSvc_i.c 
 2> TestSvc.obj：error LNK2019：未解决的外部符号__declspec（dllimport）public：__thiscall CUtils :: CUtils（void）（__imp _ ?? 0CUtils @@ QAE @ XZ）在函数_wWinMain中引用@ 16 
 2> C：\Work\TestSvc_root\Debug\TestSvc.exe：致命错误LNK1120：1个未解决的外部
 ==========重建全部：1成功，1失败，0跳过========== 
 

主项目中的代码如下所示：

  externCint WINAPI _tWinMain（HINSTANCE hInstance，HINSTANCE hPrevInstance，LPTSTR lpCmdLine，int nShowCmd）
 {
 CUtils * a = new CUtils（）; 
删除a; 
 
 return 1; 
} 
  

我有以下设置：

• 使用Visual Studio 2013以C ++编写的主项目;


• 我使用的是Unicode字符集，运行时用于共享的dll; / li>
  
• _UNICODE 被定义;


• 子系统：Windows（ / SUBSYSTEM ：WINDOWS ）;


• 我想创建一个应用于共享DLL的实用程序库。代码如下所示：

Utils.h：

  #ifdef UTILS_EXPORTS 
 #define UTILS_API __declspec（dllexport）
 #else 
 #define UTILS_API __declspec（dllimport）
 #endif 
 
 //这个类从Utils.dll 
类UTILS_API CUtils {
 public：
 CUtils（void）; 
}; 
  

Utils.cpp：

  #includestdafx.h
 #includeUtils.h
 
 //这是已经导出的类的构造函数。 
 //查看Utils.h的类定义
 CUtils :: CUtils（）
 {
 return; 
} 
  

• 我检查了dll项目设置，基本上，它们都在主项目中;


• UTILS_EXPORTS 在dll项目中定义，所以通常所有定义都应该有 __ declspec（dllexport）（如预期，未在 UTILS_EXPORTS 中定义）;


• 我具有以下预处理器定义： WIN32 ; _DEBUG ; _WINDOWS ; _USRDLL ; UTILS_EXPORTS ;


• 添加dll项目作为依赖到主项目;


• 将dll复制到 $（SolutionDir）\Debug 下，但不在 $（SolutionDir）\ $（MasterProject）\Debug - 我不知道为什么。我手动复制它，但我仍然有同样的问题;


• 我在Utils.dll上运行了 DUMPBIN 实用程序，这里是如何外观：

 
 C：\Work\TestSvc_root\Debug> DUMPBIN / EXPORTS / SYMBOLS Utils .dll 
 Microsoft（R）COFF / PE Dumper版本10.00.40219.01 
版权所有（C）Microsoft Corporation。版权所有。 
 
 
文件的转储Utils.dll 
 
文件类型：DLL 
 
部分包含以下用于Utils.dll 
 
 00000000特征
 53C632A8时间日期戳Wed Jul 16 10:07:04 2014 
 0.00版本
 1 ordinal base 
 2函数数
 2名字数
 
序数提示RVA名称
 
 1 0 00011154？0CUtils @@ QAE @ XZ = @ ILT + 335（？0CUtils @@ QAE @ XZ）
 2 1 000110C8 ?? 4CUtils @@ QAEAAV0 @ ABV0 @@ Z = @ ILT + 195（？4CUtils @@ QAEAAV0 @ ABV0 @@ Z）
 
摘要
 
 1000 .data 
 1000 .idata 
 2000 .rdata 
 1000 .reloc 
 1000 .rsrc 
 4000 .text 
 10000 .textbss 
 

• 我试图嗅UTILS_API的价值：

 
 #define DO_QUOTE（X）#X 
 #define QUOTE（X）DO_QUO TE（X）
 #define MY_QUOTED_VAR QUOTE（MYVARIABLE）
 
 #pragma message（QUOTE（UTILS_API））
 

它转储正确的值：当从dllused转储 __ declspec（dllexport）时，当从main-project使用它转储 __ declspec（dllimport）

所以，任何提示？它似乎有一些与类导出定义/方法装饰有关的东西...在以前的普通旧Visual C ++中，曾经是一个def文件，您可以在其中映射导出的名称...但在这个新版本，我迷路了。

谢谢！

解决方案

，您可以将.lib文件（在.dll生成期间生成）显式添加到主项目的链接器选项中的输入库列表。

I know similar question has been asked before, but it looks like there is something different in what concerns classes export than a simple function ... I have checked all those solutions, checked all the suggestions but it still looks like I am missing something ...

What's happening:

• I have a master C++ project written in Visual Studio 2013 and I want to add a dll library with various utils. I have created a dummy one, with basically no functionality, but it fails to compile:

    2>  TestSvc_i.c
    2>TestSvc.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall CUtils::CUtils(void)" (__imp_??0CUtils@@QAE@XZ) referenced in function _wWinMain@16
    2>C:\Work\TestSvc_root\Debug\TestSvc.exe : fatal error LNK1120: 1 unresolved externals
    ========== Rebuild All: 1 succeeded, 1 failed, 0 skipped ==========

And the code in the main project looks like this:

extern "C" int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nShowCmd)
{
    CUtils *a = new CUtils();
    delete a;

    return 1;
}

I have the following setup:

• the master project written in C++ with Visual Studio 2013;
• I am using Unicode charset and the runtime is used in a shared dll;
• _UNICODE is defined;
• SubSystem: Windows (/SUBSYSTEM:WINDOWS);
• I want to create an utility library that should be used in a shared dll. The code looks like this:

Utils.h:

#ifdef UTILS_EXPORTS
#define UTILS_API __declspec(dllexport)
#else
#define UTILS_API __declspec(dllimport)
#endif

// This class is exported from the Utils.dll
class UTILS_API CUtils {
public:
    CUtils(void);
};

Utils.cpp:

#include "stdafx.h"
#include "Utils.h"

// This is the constructor of a class that has been exported.
// see Utils.h for the class definition
CUtils::CUtils()
{
    return;
}

• I checked the dll-project settings and basically, they're all as in main project;
• UTILS_EXPORTS is defined in dll-project so normally, all definitions should have __declspec(dllexport) (as expected, not defined in UTILS_EXPORTS);
• I have the following preprocessor definitions: WIN32;_DEBUG;_WINDOWS;_USRDLL;UTILS_EXPORTS;
• dll-project is added as a dependency to master-project;
• the dll is copied under $(SolutionDir)\Debug but not under $(SolutionDir)\$(MasterProject)\Debug - I don't know why. I manually copied it, but I still have the same problem;
• I ran DUMPBIN utility on Utils.dll and here is how it looks:

    C:\Work\TestSvc_root\Debug>DUMPBIN /EXPORTS /SYMBOLS Utils.dll
    Microsoft (R) COFF/PE Dumper Version 10.00.40219.01
    Copyright (C) Microsoft Corporation.  All rights reserved.


    Dump of file Utils.dll

    File Type: DLL

      Section contains the following exports for Utils.dll

    00000000 characteristics
    53C632A8 time date stamp Wed Jul 16 10:07:04 2014
        0.00 version
           1 ordinal base
           2 number of functions
           2 number of names

    ordinal hint RVA      name

          1    0 00011154 ??0CUtils@@QAE@XZ = @ILT+335(??0CUtils@@QAE@XZ)
          2    1 000110C8 ??4CUtils@@QAEAAV0@ABV0@@Z = @ILT+195(??4CUtils@@QAEAAV0@ABV0@@Z)

    Summary

        1000 .data
        1000 .idata
        2000 .rdata
        1000 .reloc
        1000 .rsrc
        4000 .text
       10000 .textbss

• I have tried to "sniff" the value of UTILS_API:

    #define DO_QUOTE(X)        #X
    #define QUOTE(X)           DO_QUOTE(X)
    #define MY_QUOTED_VAR      QUOTE(MYVARIABLE)

    #pragma message(QUOTE(UTILS_API))

which dumps the correct value: when "used" from dll, it dumps __declspec(dllexport), and when used from main-project it dumps __declspec(dllimport)

So, any hint? It looks like there is something that has to do with class export definition/method decoration ... In previous plain old Visual C++ there used to be a "def" file where you could map the exported names ... but in this new version, I am lost.

Thanks!

解决方案

As a workaround, you may explicitly add .lib file (generated during the build of your .dll) to the list of input libraries in the linker options of the main project.

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