Question

我正在学习COM。 Visual Studio 2013. C ++上的DLL x64项目（COM组件）。

当我尝试编译“Hello World”项目时，我收到错误：

Error   1   error LNK2001: unresolved external symbol DllCanUnloadNow   C:\COMInteropSample\my_com_sandbox\my_com_component_01\my_com_component_01.def

Error   2   error LNK2001: unresolved external symbol DllGetClassObject C:\COMInteropSample\my_com_sandbox\my_com_component_01\my_com_component_01.def

Error   3   error LNK2001: unresolved external symbol DllRegisterServer C:\COMInteropSample\my_com_sandbox\my_com_component_01\my_com_component_01.def

Error   4   error LNK2001: unresolved external symbol DllUnregisterServer   C:\COMInteropSample\my_com_sandbox\my_com_component_01\my_com_component_01.def

Error   5   error LNK1120: 4 unresolved externals   C:\COMInteropSample\my_com_sandbox\Debug\my_com_component_01.lib    my_com_component_01

但我不明白这些错误的原因......我正在查看我的DEF和CPP文件，我看到没有错误。：（（（

my_com_component_01.def档案的内容：

LIBRARY my_com_component_01.dll
EXPORTS
  DllMain PRIVATE
  DllGetClassObject PRIVATE
  DllRegisterServer PRIVATE
  DllUnregisterServer PRIVATE
  DllCanUnloadNow PRIVATE

我的dll.cpp文件的内容（导出功能的定义）：

/* dll.cpp */
#include <objbase.h>
#include <sal.h>
#include "tools.h"
#include "global_vars.h"
#include "CA.h"
#include "My_com_factory.h"

static HINSTANCE pDll = nullptr;

extern "C" {

  BOOL WINAPI DllMain(_In_ HINSTANCE hinstDLL, _In_ DWORD fdwReason,
    _In_ LPVOID lpvReserved){
    char* s = nullptr;
    if (DLL_PROCESS_ATTACH == fdwReason){
      s = "DLL_PROCESS_ATTACH";
    }
    else if (DLL_PROCESS_DETACH == fdwReason){
      s = "DLL_PROCESS_DETACH";
    }
    else if (DLL_THREAD_ATTACH == fdwReason){
      s = "DLL_THREAD_ATTACH";
    }
    else if (DLL_THREAD_DETACH == fdwReason){
      s = "DLL_THREAD_DETACH";
    }
    pDll = hinstDLL;
    std::cout << "DllMain: ";
    trace(s);
    return true;
  }

  HRESULT __stdcall DllGetClassObject(_In_  REFCLSID rclsid,
    _In_  REFIID riid, _Out_ LPVOID *ppv){
    if (_uuidof(CA) == rclsid){
      My_com_factory* mf = new My_com_factory();
      HRESULT hr = mf->QueryInterface(riid, ppv);
      return hr;
    }
    else{
      *ppv = nullptr;
      return CLASS_E_CLASSNOTAVAILABLE;
    }
  }

  // TODO: Is not implemented still.
  HRESULT __stdcall DllRegisterServer(){
    return S_OK;
  }

  // TODO: Is not implemented still.
  HRESULT __stdcall DllUnregisterServer(){
    return S_OK;
  }

  HRESULT __stdcall DllCanUnloadNow(){
    return (obj_count == 0 && locks_count == 0) ? S_OK : S_FALSE;
  }
}

我做错了什么？

谢谢。

P.S.to πάνταῥεῖ 你看起来不太对劲。在没有调查问题本质的情况下给出答案是很糟糕的。我找到了IDE不良行为的原因并予以纠正。我认为这是Visual Studio 2013的一个错误。

为什么我为自己的函数获取“未解析的外部符号”消息？

0 个答案: