Error using mex : "Undefined symbols for architecture x86_64: ... "

I am using MATLAB R2015b on Mac. I try to run a very simple cpp file using mex in MATLAB, like the following function:

#include "mex.h"
#include "stdio.h"
#include "iostream"

void testFile()
{
  int i=4;
  std::cout<<i;
}

But the following error occurs:

Building with 'Xcode Clang++'.
Error using mex
Undefined symbols for architecture x86_64:
  "_mexFunction", referenced from:
     -exported_symbol[s_list] command line option
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

However using "make testFile()" in Terminal works well. I studied some solutions in MathWorks but did not work.

Any help would be appreciated.

Thanks,

Answer 1

[Steven Lord]

You MUST define a function named mexFunction in your MEX-file and that function must have a specific signature. Your source code file does not define a function with that name, so it is not a valid MEX-file and when you attempt to build it as though it was a valid MEX-file the compiler correctly complains.

[James Tursa]

E.g.,

#include "mex.h"
#include "stdio.h"
#include "iostream"

void testFile()
{
  int i=4;
  std::cout<<i;
}

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    testFile();
}

See this link:

http://www.mathworks.com/help/matlab/apiref/mexfunction.html?searchHighlight=mexfunction

[Shima Asaadi]

Many thanks to all.

And sorry for such a basic problem.