MATLAB Shared Library

Abbas_Riazi

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30 Dec 20032 min read

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Using MATLAB compiler to build a shared library (DLL) from m-File.

Download demo project - 63.9 Kb

Introduction

Some times it is required that we build a shared library (DLL) from an m-file. M-files are functions that are written in Matlab editor and can be used from Matlab command prompt. In m-files, we employ Matlab built-in functions or toolbox functions to compute something. In my past articles, I showed you some ways to use Matlab engine (vis. API, C++ class or Matlab engine API) for employing Matlab built-in functions, but what about functions that we develop? How can we use them in VC? Is there any interface? This article shows you an idea to employ your own Matlab functions.

Shared Libraries

Shared libraries or DLLs are files that export some functions. We can use exported functions in any language. Here is a brief instruction to build shared libraries from Matlab m-files:

Compile your m-file into a DLL (from Matlab command prompt):
```
mcc -t -L C -W lib:mylib -T link:lib -h <M-file> libmmfile.mlib
```
The -t option tells the Matlab compiler to translate the m-file to the target language. The -L option specifies the target language, which is chosen to be C. The -W option tells the Matlab compiler to build a wrapper for the library with the name specified by "lib:". The -T option tells the compiler what stage should be reached and for what intentions. Here we link our application together to build a shared library (DLL). Specifying libmmfile.mlib tells Matlab compiler to link against Matlab m-file math routine.

This step will produce mylib.dll, mylib.lib and mylib.h. For debugging purposes, you can add the -g switch to produce a DLL suitable for debugging in MSVC.

For example, I wrote my own mean function and saved it as MeanFunction.m:
```
function y=MeanFunction(x)
[m,n]=size(x);
k=0;
for i=1:n
    k=k+x(i);
end
y=k/n;
```
and compiled it with mcc:
```
mcc -t -L C -W lib:MeanFunctionLib -T link:lib MeanFunction.m libmmfile.mlib
```

Create your project in VC. In your main CPP file, include your function header file and add the related library. Here I create a simple console application. Make sure to call initialization and termination routines from your code before and after of calling the m-file function.

#include "stdafx.h"
#include "matlab.h"
#include "MeanFunctionLib.h"

#pragma comment(lib, "libmx.lib")
#pragma comment(lib, "libmatlb.lib")
#pragma comment(lib, "libmat.lib")
#pragma comment(lib, "libmmfile.lib")
#pragma comment(lib, "MeanFunctionLib.lib")

int main(int argc, char* argv[])
{
    mxArray* result;
    mxArray* x;
    double myArray[5]={10.2, 3, 6.3, 5.4, 5.9};
    
    x=mxCreateDoubleMatrix(1, 5, mxREAL);
    memcpy(mxGetPr(x), myArray, 5 * sizeof(double));

    MeanFunctionLibInitialize();

    result=mlfMeanfunction(x);
    
    MeanFunctionLibTerminate();

    mlfPrintMatrix(result);

    mxDestroyArray(x);
    mxDestroyArray(result);

    return 0;
}

Build your project.

Notice that you must use Matlab C API or Matlab C++ class library to use mxArray or mwArray. For more information, refer to my articles:

Enjoy!

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

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Written By

Abbas_Riazi

CEO Solaris Electronics LLC

United Arab Emirates

I was born in Shiraz, a very beautiful famous city in Iran. I started programming when I was 12 years old with GWBASIC. Since now, I worked with various programming languages from Basic, Foxpro, C/C++, Visual Basic, Pascal to MATLAB and now Visual C++.
I graduated from Iran University of Science & Technology in Communication Eng., and now work as a system programmer for a telecommunication industry.
I wrote several programs and drivers for Synthesizers, Power Amplifiers, GPIB, GPS devices, Radio cards, Data Acquisition cards and so many related devices.
I'm author of several books like Learning C (primary and advanced), Learning Visual Basic, API application for VB, Teach Yourself Object Oriented Programming (OOP) and etc.
I'm winner of January, May, August 2003 and April 2005 best article of month competition, my articles are:

You can see list of my articles, by clicking here

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MATLAB Shared Library

Introduction

Shared Libraries

License

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