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I got lots of trouble to call c function from matlab.

My c function is simple

test.c

#include "mex.h"

int addOne(int a)
{
    return a+1;
}

I typed mex test.c in matlab command window, I got this error message

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)

    mex: link of ' "test.mexmaci64"' failed.

My Matlab is 2013a, osx 10.9, xcode 5.02

Does anybody have an idea about this? Thanks.

fnhdx
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    I think you may need to read more about `mex`. Where's your gateway function, `mexFunction`? Try starting [here](http://www.mathworks.com/help/matlab/matlab_external/standalone-example.html), or any other example. [More here](http://www.mathworks.com/help/matlab/write-cc-mex-files.html). – horchler Sep 26 '14 at 03:46

1 Answers1

2

Here is a quick example to get you started:

addOne.cpp

#include "mex.h"

double addOne(double a)
{
    return a+1;
}

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    if (nrhs!=1 || nlhs>1) mexErrMsgIdAndTxt("mex:error", "Wrong num of args");
    if (!mxIsDouble(prhs[0])) mexErrMsgIdAndTxt("mex:error", "Not double");

    plhs[0] = mxDuplicateArray(prhs[0]);

    double *x = mxGetPr(plhs[0]);
    size_t len = mxGetNumberOfElements(plhs[0]);
    for (size_t i=0; i<len; ++i) {
        x[i] = addOne(x[i]);
    }
}

MATLAB:

>> mex -largeArrayDims addOne.cpp
>> x = magic(4)
x =
    16     2     3    13
     5    11    10     8
     9     7     6    12
     4    14    15     1
>> addOne(x)
ans =
    17     3     4    14
     6    12    11     9
    10     8     7    13
     5    15    16     2
Amro
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