Unable to resolve error LNK2019: unresolved external symbol

问题

I have a solution in Visual Studio, it has 2 projects namely PAL_TEST and Unit_Test.
I have a class in PAL_TEST, CPALResponse.h

#include "CFW_Stl.h"

class CPALResponse
{
  public:
    void SetCommandSucceeded(bool bCommandSucceeded = false);
    bool GetCommandSucceeded();
    void SetCommandType(int nCommandType);
    int GetCommandType();

  private:
    bool m_bCommadSucceeded;
    int m_nCommandType;
};

another file in PAL_TEST CPALResponse.cpp

#include "stdafx.h"
#include "CFW_CPALResponse.h"

void CPALResponse::SetCommandSucceeded(bool bCommandSucceeded)
{
    m_bCommadSucceeded = bCommandSucceeded;
}
bool CPALResponse::GetCommandSucceeded()
{
    return m_bCommadSucceeded;
}
void CPALResponse::SetCommandType(int nCommandType)
{
    m_nCommandType = nCommandType;
}
int CPALResponse::GetCommandType()
{
    return m_nCommandType;
}

There is a file Unit_Test.cpp in Unit_Test,

#include "stdafx.h"
#include "../PAL_TEST/CFW_CPALResponse.h"

int _tmain(int argc, _TCHAR* argv[])
{
    CPALResponse a;
    a.SetCommandSucceeded(true);
    return 0;
}

When I build the Unit_Test project it shows me

1>------ Build started: Project: Unit_Test, Configuration: Debug Win32 ------
1>Linking...
1>Unit_Test.obj : error LNK2019: unresolved external symbol "public: void __thiscall CPALResponse::SetCommandSucceeded(bool)" (?SetCommandSucceeded@CPALResponse@@QAEX_N@Z) referenced in function _wmain
1>C:\Users\anubhav.a\Documents\Visual Studio 2008\Projects\PAL_TEST\Debug\Unit_Test.exe : fatal error LNK1120: 1 unresolved externals
1>Build log was saved at "file://c:\Users\anubhav.a\Documents\Visual Studio 2008\Projects\PAL_TEST\Unit_Test\Debug\BuildLog.htm"
1>Unit_Test - 2 error(s), 0 warning(s)

It is unclear to me what the message means and how to resolve the error

回答1:

Here's the usual checklist, your problem is one of these:

You're not exporting the class with declspec(dllexport) nor importing them in the calling project with declspec(dllimport).
Make sure you compile the file with the implementations.
Make sure the project that uses the class links against the .lib generated by the first project.

来源：https://stackoverflow.com/questions/11429971/unable-to-resolve-error-lnk2019-unresolved-external-symbol

标签

c++

visual-studio-2008

lnk2019