How to build .m files into .mex files correctly

Hi All,

I am trying to build all my M files into MEX files so that I can give them to other users to use without disclosing the source code. I used the following steps to create (suppose I have a function blank saved in blank.m, code pasted down at the bottom):

Platform: Windows 7, with Matlab 2010b, visual studio 2010

1. convert M into C++ header and Library by:

 mcc -W cpplib:blank -T link:lib blank.m

2. Use the generated blank.h and blank.lib, I create a blankm.cpp which looks like

void mexFunction(int nlhs,
               mxArray* plhs[],
               int nrhs,
               mxArray* prhs[])
{
  //  validate input argument number
  if (nrhs < 1)
  {
      mexErrMsgTxt("At least the file name is required.");
  }
  else if (nrhs > 1)
  {
      mexErrMsgTxt("Too many input arguments.");
  }

    //  validate output argument number
    if (nlhs > 1)
    {
        mexErrMsgTxt("Too many output arguments.");
    }
    mlxBlank(nlhs,
             plhs,
             nrhs,
             prhs);
}

3. Then, I compiled it using matlab:

 mex blankm.cpp -L blank.lib

Or compile it in Visual Studio 2010. All of the above steps went well with no problem. So far I have generated blankm.mexw64 successfully. If I input the following script in Matlab, it comes out with nothing

 blandm(' a ')

However, if I input like

 a = blankm(' a ');

I'll get an error

 ??? One or more output arguments not assigned during call to "blankm".

Any idea on this? I did something wrong. Or, the whole path is not correct? Thank you in advance. function str2 = blank(str)

    if ischar(str)
       str2 = fliplr(deblank(fliplr(deblank(str))));
    else
        error(['input is not a string']);
    end
end

Answer 1

[Kaustubha Govind]

Shared libraries generating using MATLAB Compiler are meant for deploying on a machine that does not have MATLAB installed - this is not needed in your case since you only want code-protection.

Why not simply pcode your MATLAB-files? If you absolutely want to create a MEX-file however, the better option might be to use MATLAB Coder which will generate standalone C code from your MATLAB functions where possible. If some of your MATLAB code is not supported for code generation, they will be converted into mexCallMATLAB calls.

Answer 2

[Ran]

The content of generated blank.h is as below:

//
// MATLAB Compiler: 4.14 (R2010b)
// Date: Wed Jun 06 16:53:38 2012
// Arguments: "-B" "macro_default" "-W" "cpplib:blank" "-T" "link:lib"
// "blank.m" 
//

#ifndef __blank_h
#define __blank_h 1

#if defined(__cplusplus) && !defined(mclmcrrt_h) && defined(__linux__)
#  pragma implementation "mclmcrrt.h"
#endif
#include "mclmcrrt.h"
#include "mclcppclass.h"
#ifdef __cplusplus
extern "C" {
#endif

#if defined(__SUNPRO_CC)
/* Solaris shared libraries use __global, rather than mapfiles
 * to define the API exported from a shared library. __global is
 * only necessary when building the library -- files including
 * this header file to use the library do not need the __global
 * declaration; hence the EXPORTING_<library> logic.
 */

#ifdef EXPORTING_blank
#define PUBLIC_blank_C_API __global
#else
#define PUBLIC_blank_C_API /* No import statement needed. */
#endif

#define LIB_blank_C_API PUBLIC_blank_C_API

#elif defined(_HPUX_SOURCE)

#ifdef EXPORTING_blank
#define PUBLIC_blank_C_API __declspec(dllexport)
#else
#define PUBLIC_blank_C_API __declspec(dllimport)
#endif

#define LIB_blank_C_API PUBLIC_blank_C_API

#else

#define LIB_blank_C_API

#endif

/* This symbol is defined in shared libraries. Define it here
 * (to nothing) in case this isn't a shared library. 
 */
#ifndef LIB_blank_C_API 
#define LIB_blank_C_API /* No special import/export declaration */
#endif

extern LIB_blank_C_API 
bool MW_CALL_CONV blankInitializeWithHandlers(
       mclOutputHandlerFcn error_handler, 
       mclOutputHandlerFcn print_handler);

extern LIB_blank_C_API 
bool MW_CALL_CONV blankInitialize(void);

extern LIB_blank_C_API 
void MW_CALL_CONV blankTerminate(void);

extern LIB_blank_C_API 
void MW_CALL_CONV blankPrintStackTrace(void);

extern LIB_blank_C_API 
bool MW_CALL_CONV mlxBlank(int nlhs, mxArray *plhs[], int nrhs, mxArray *prhs[]);

extern LIB_blank_C_API 
long MW_CALL_CONV blankGetMcrID();

#ifdef __cplusplus
}
#endif

#ifdef __cplusplus

/* On Windows, use __declspec to control the exported API */
#if defined(_MSC_VER) || defined(__BORLANDC__)

#ifdef EXPORTING_blank
#define PUBLIC_blank_CPP_API __declspec(dllexport)
#else
#define PUBLIC_blank_CPP_API __declspec(dllimport)
#endif

#define LIB_blank_CPP_API PUBLIC_blank_CPP_API

#else

#if !defined(LIB_blank_CPP_API)
#if defined(LIB_blank_C_API)
#define LIB_blank_CPP_API LIB_blank_C_API
#else
#define LIB_blank_CPP_API /* empty! */ 
#endif
#endif

#endif

extern LIB_blank_CPP_API void MW_CALL_CONV blank(int nargout, mwArray& str2, const mwArray& str);

#endif
#endif

Answer 3

[Ran]

Hi Kaustubha,

Thank you. It does sound good. I'll give it a try. It should be the thing I am looking for. Thanks again.

[Kaustubha Govind]

Ran: Could you please accept my answer if it helps. Thanks!