MEX link failed

I met link failed problem when I compiling mex code. I'm using matlab r2011a, with win7, and I got the same result under linux.

Error Message:

D:\Study Stuff\Robust PCA\Robust PCA\src\ENV\packages\PROPACK>mex reorth_mex.c

    Writing library for reorth_mex.mexw32

    *c:\users\lofi\appdata\local\temp\mex_ufvcxe\reorth_mex.obj .text: undefined reference to '_reorth_'*

    D:\PROGRA~1\MATLAB\R2011A\BIN\MEX.PL: Error: Link of 'reorth_mex.mexw32' 
  failed.

Source Code:

#include <string.h>

#include "mex.h"

/* Template for reorth: */

void reorth_(int *n, int *k, double *V, int *ldv, double *vnew,
      double *normvnew, double *index, double *alpha, double *work,
      int *iflag, int *nre);

/* Here comes the gateway function to be called by Matlab: */
void mexFunction(int nlhs, mxArray *plhs[], 
     int nrhs, const mxArray *prhs[])
{
  int n, k1, k, imethod, inre;
  double *work;

    if (nrhs != 6)
       mexErrMsgTxt("reorth requires 6 input arguments");
    else if  (nlhs < 2)
       mexErrMsgTxt("reorth requires at least 2 output arguments");

    n = mxGetM(prhs[0]); /* get the dimensions of the input */
    k1 = mxGetN(prhs[0]);
    k = mxGetM(prhs[3]) * mxGetN(prhs[3]);

    /* Create/allocate return argument, a 1x1 real-valued Matrix */
    plhs[0]=mxCreateDoubleMatrix(n,1,mxREAL); 
    plhs[1]=mxCreateDoubleMatrix(1,1,mxREAL); 
    if (nlhs>2) 
      plhs[2]=mxCreateDoubleMatrix(1,1,mxREAL); 

    work = mxCalloc(k,sizeof(double));

    memcpy(mxGetPr(plhs[0]),mxGetPr(prhs[1]), n*sizeof(double));
    memcpy(mxGetPr(plhs[1]),mxGetPr(prhs[2]), sizeof(double));
    imethod = (int) mxGetScalar(prhs[5]);

    reorth_(&n, &k, mxGetPr(prhs[0]), &n, mxGetPr(plhs[0]), 
      mxGetPr(plhs[1]), mxGetPr(prhs[3]), mxGetPr(prhs[4]), 
      work,&imethod,&inre);
    if (nlhs>2) 
      *(mxGetPr(plhs[2])) = (double) inre*k;

    mxFree(work);
  }

Answer 1

[Jan]

Where is the definition of reorth_? It must be either included in reorth_mex.c or added to the mex command.