C++ error when using MatLab dll: one or more multiply defined symbols found

Hi,

I am trying to use a MatLab function in C++ by using the MCR (MatLab Compiler Runtime). However, I get an error when I call the function from C++.

This is the output when I try to build:

1>------ Build started: Project: MatLab DLL Test 2, Configuration: Debug x64 ------

1>Compiling...

1>main.cpp

1>libfoo.cpp

1>Generating Code...

1>Linking...

1>libfoo.lib(libfoo.dll) : error LNK2005: "void __cdecl foo(int,class mwArray &,class mwArray const &)" (?foo@@YAXHAEAVmwArray@@AEBV1@@Z) already defined in libfoo.obj

1>libfoo.lib(libfoo.dll) : error LNK2005: "void __cdecl foo(int,class mwArray &,class mwArray const &)" (?foo@@YAXHAEAVmwArray@@AEBV1@@Z) already defined in libfoo.obj

1>C:\Users\fmarsman\Documents\Visual Studio 2008\Projects\Project1\MatLab DLL Test 2\x64\Debug\MatLab DLL Test 2.exe : fatal error LNK1169: one or more multiply defined symbols found

1>Build log was saved at "file://c:\Users\fmarsman\Documents\Visual Studio 2008\Projects\Project1\MatLab DLL Test 2\MatLab DLL Test 2\x64\Debug\BuildLog.htm"

1>MatLab DLL Test 2 - 3 error(s), 0 warning(s)

========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

This is what I have done:

• I created the .m file foo.m:

function y = foo(x)

y = x + 1;

• In command prompt, I executed:

mcc –W cpplib:libfoo –T link:lib foo

• This created libfoo.lib, libfoo.h libfoo.dll and libfoo.cpp
• Next, I created a project in MS Visual Studio 2008. I added libfoo.cpp to 'Source Files' and libfoo.h to 'Header Files'.I added three directories to Configuration Properties -> C/C++ -> General -> Additional Include Directories:

C:\Users\fmarsman\Documents\MATLAB\DLL Test 2 (the folder where all the libfoo.* are)

C:\Program Files\MATLAB\MATLAB Compiler Runtime\v82\extern\lib\win64\microsoft (for the mclmcrrt.lib)

C:\MATLAB\R2013b\extern\include (for mclmcrrt.h)

• To Linker -> Input -> Additional Dependencies I added:

"C:\Program Files\MATLAB\MATLAB Compiler Runtime\v82\extern\lib\win64\microsoft\mclmcrrt.lib"

"C:\Users\fmarsman\Documents\MATLAB\DLL Test 2\libfoo.lib"

My source code:

#include <iostream>
#include <mclmcrrt.h>
#include <mclcppclass.h>
#include <libfoo.h>
using namespace std;

int main( ) {
  mclInitializeApplication(NULL,0);
  libfooInitialize( );

    mwArray y(1, 1, mxDOUBLE_CLASS);
    y = 3.0;
    const mwArray x = y.Clone();

    foo(1,y,x);

    mclTerminateApplication( );
    libfooTerminate( );

    return 0;
} // main

I've been trying to find a solution all day but without success. I really hope someone can help me with this.

Answer 1

[Frank]

I've got the answer on stackoverflow.com; the only thing I needed to do was removing libfoo.cpp from my project.