MATLAB dll in Visual C++

I am trying to call a very simple MATLAB function from my Visual C++ code, but despite the endless number of tutorials on how to do this (e.g. this one ), I keep getting the same errors.

I use the Library Compiler in MATLAB R2016b to generate TestingDLLMain.dll, and Visual Studio 2012 (11.0). I downloaded the MCR for MATLAB R2016b.

This is my MATLAB function:

function [number] = TestingDLL(n)

number = n+1;

end

And C++:

#include "stdafx.h"
#include <iostream>
#include "TestingDLLMain.h"

int _tmain(int argc, _TCHAR* argv[])
{
  // initialize MCR and lib
    if (!mclInitializeApplication(NULL,0))  {
        std::cerr << "could not initialize the application" << std::endl;
        return -1;
    }
    if(!TestingDLLMainInitialize()) {
        std::cerr << "Could not initialize the library" << std::endl;
        return -1;
    }

      try {

    // create input
        double a[] = {1.0, 2.0, 3.0, 4.0};

          mwArray in1(2, 2, mxDOUBLE_CLASS, mxREAL);

          in1.SetData(a, 4);

          // call function
          mwArray out;
          TestingDLL(1, out, in1);

          // show result
          std::cout << "in1 + 1 = " << out << std::endl;

  }
  catch (const mwException& e) {
        std::cerr << e.what() << std::endl;
    return -2;
  }

  return 0;
}

The error:

1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _mclInitializeApplication_860_proxy referenced in function _wmain
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _ref_count_obj_addref_proxy referenced in function "public: __thiscall mwException::mwException(class mwException const &)" (??0mwException@@QAE@ABV0@@Z)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _ref_count_obj_release_proxy referenced in function "public: virtual __thiscall mw_auto_ptr_t<class char_buffer>::~mw_auto_ptr_t<class char_buffer>(void)" (??1?$mw_auto_ptr_t@Vchar_buffer@@@@UAE@XZ)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _char_buffer_get_buffer_proxy referenced in function "public: __thiscall mwString::operator char const *(void)const " (??BmwString@@QBEPBDXZ)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _array_ref_to_string_proxy referenced in function "public: class mwString __thiscall mwArray::ToString(void)const " (?ToString@mwArray@@QBE?AVmwString@@XZ)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _array_ref_set_numeric_mxDouble_proxy referenced in function "public: void __thiscall mwArray::SetData(double *,unsigned int)" (?SetData@mwArray@@QAEXPANI@Z)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _error_info_get_message_proxy referenced in function "public: virtual char const * __thiscall mwException::what(void)const " (?what@mwException@@UBEPBDXZ)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _mclcppGetLastError_proxy referenced in function "public: static void __cdecl mwException::raise_error(void)" (?raise_error@mwException@@SAXXZ)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _mclcppCreateError_proxy referenced in function "public: __thiscall mwException::mwException(class error_info *,bool)" (??0mwException@@QAE@PAVerror_info@@_N@Z)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _mclGetEmptyArray_proxy referenced in function "public: __thiscall mwArray::mwArray(void)" (??0mwArray@@QAE@XZ)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _mclGetMatrix_proxy referenced in function "public: __thiscall mwArray::mwArray(unsigned int,unsigned int,enum mxClassID,enum mxComplexity)" (??0mwArray@@QAE@IIW4mxClassID@@W4mxComplexity@@@Z)
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol _TestingDLLMainInitialize referenced in function _wmain
1>ConsoleApplication3.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) void __cdecl TestingDLL(int,class mwArray &,class mwArray const &)" (__imp_?TestingDLL@@YAXHAAVmwArray@@ABV1@@Z) referenced in function _wmain
1>C:\Users\vrt9ti\Documents\Visual Studio 2012\Projects\ConsoleApplication3\Debug\ConsoleApplication3.exe : fatal error LNK1120: 13 unresolved externals

Answer 1

[Kojiro Saito]

It seems the linker has a problem. Could you confirm mclmcrrt.lib was added to "Additional Dependencies" under the Linker ->Input tab?

[Tina]

It seems so, yes. Is it possible that things don't work due to incompatibility issues? Or did I add the library in a wrong way, if that is even possible? I just typed "mclmcrrt.lib" into the field. In a previous project, I added another library in the same way and that worked fine.

[Kojiro Saito]

Just "mclmcrrt.lib" works. In your previous project, did you define Solution Platforms as "Win32"? It should be x64.

I've just tested Visual Studio 2012 and MATLAB / MATLAB Runtime R2016b. Since MATLAB R2016b dll only supports 64bit OS, you should change target platform from Win32 or x86 to x64.