Mixing native C++ and C++/CLI

Question

I have a solution which consists of a native C++ DLL and a C++/CLI wrapper. My aim is to create a wrapper in C++/CLI of the native C++ DLL.

Whenever I try to create an instance of a native C++ class within the wrapper, I am met with many linker errors (see below).

2>  .NETFramework,Version=v4.0.AssemblyAttributes.cpp
2>NFileOperation.obj : error LNK2028: unresolved token (0A000208) "public: static bool __cdecl CFileOperation::FileExists(class ATL::CStringT<wchar_t,class ATL::StrTraitATL<wchar_t,class ATL::ChTraitsCRT<wchar_t> > > const &)" (?FileExists@CFileOperation@@$$FSA_NABV?$CStringT@_WV?$StrTraitATL@_WV?$ChTraitsCRT@_W@ATL@@@ATL@@@ATL@@@Z) referenced in function "[T2M] void __clrcall `dynamic initializer for 'public: static float * tagVARIANT::* ATL::CVarTypeInfo<float *>::pmField''(void)" (__t2m@???__E?pmField@?$CVarTypeInfo@PAM@ATL@@2QQtagVARIANT@@PAMQ3@@@YMXXZ@?A0x22b777aa@@YMXXZ)
2>DeskUpdateManaged.obj : error LNK2028: unresolved token (0A00021C) "public: static bool __cdecl CFileOperation::FileExists(class ATL::CStringT<wchar_t,class ATL::StrTraitATL<wchar_t,class ATL::ChTraitsCRT<wchar_t> > > const &)" (?FileExists@CFileOperation@@$$FSA_NABV?$CStringT@_WV?$StrTraitATL@_WV?$ChTraitsCRT@_W@ATL@@@ATL@@@ATL@@@Z) referenced in function "public: bool __clrcall DeskUpdateManaged::Conversion::FileExist(class System::String ^)" (?FileExist@Conversion@DeskUpdateManaged@@$$FQ$AAM_NP$AAVString@System@@@Z)
2>DeskUpdateManaged.obj : error LNK2019: unresolved external symbol "public: static bool __cdecl CFileOperation::FileExists(class ATL::CStringT<wchar_t,class ATL::StrTraitATL<wchar_t,class ATL::ChTraitsCRT<wchar_t> > > const &)" (?FileExists@CFileOperation@@$$FSA_NABV?$CStringT@_WV?$StrTraitATL@_WV?$ChTraitsCRT@_W@ATL@@@ATL@@@ATL@@@Z) referenced in function "public: bool __clrcall DeskUpdateManaged::Conversion::FileExist(class System::String ^)" (?FileExist@Conversion@DeskUpdateManaged@@$$FQ$AAM_NP$AAVString@System@@@Z)
2>NFileOperation.obj : error LNK2001: unresolved external symbol "public: static bool __cdecl CFileOperation::FileExists(class ATL::CStringT<wchar_t,class ATL::StrTraitATL<wchar_t,class ATL::ChTraitsCRT<wchar_t> > > const &)" (?FileExists@CFileOperation@@$$FSA_NABV?$CStringT@_WV?$StrTraitATL@_WV?$ChTraitsCRT@_W@ATL@@@ATL@@@ATL@@@Z)
2>C:\Users\ABGZAMANK\Music\DeskUpdate\Dev\Source\Solution\Debug\DeskUpdateManaged.dll : fatal error LNK1120: 3 unresolved externals

Function call within the C++/CLI to the native C++ DLL:

bool NFileOperation::FileExists(CAtlString sPathName)
{
    return CFileOperation::FileExists(sPathName);
}

Is there a more adequate approach to what I am trying to achieve? Any advice relating to the issue is much appreciated.

Right click your project -> properties -> linker. On the general site specify the additional library directory. On the input site specify the output .lib as an additional dependency. — Nico Schertler

eladidan eladidan · Accepted Answer · 2013-02-13T10:05:21

It seems that your native C++ code is using ATL/MFC. Assuming you are compiling under VS, go to the C++/CLI project's project properties->Configuration properties->General and select "Use of MFC" and "Use of ATL" to be either static library or shared dll (depending on your project type). This flag will add the necessary include paths, linking paths and libs to your project to make use of ATL/MFC types from within your project. Also, make sure that you are linking your C++/CLI project against your native C++ project to avoid linking errors from your project (easily found in the Linker segment of the project properties in General and Input).

Mixing native C++ and C++/CLI

1 Answers