MATLAB: Passing value from mex file to Matlab

matlab mex

Am writing a multi threaded program in Matalb..Hence am taking the support of Mex to do…Am having some set of variable in the mex space..which I want to return it back to the Matlab workspace..Please somebody tell how to do it..

Best Answer

Hi,

#include "mex.h"
void manipulate(double* y){
 *y = 20;   
}
void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    plhs[0] = mxCreateDoubleScalar(10);
    //uncomment this get the the value 20 in MATLAB, otherwise you get 10
    //manipulate(mxGetPr(plhs[0]));
}

Overall i think the best is to get started in the MEX documentation or here or take a look at some examples.

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MATLAB: Building Mex file with Fortan

Your main problem is that you need to create the output array PLHS(1) before you access it. Also your NLHS and NRHS types are wrong. Try this:

#include <fintrf.h>
C
C Gateway routine
C
    SUBROUTINE MEXFUNCTION(NLHS, PLHS, NRHS, PRHS)
    implicit none
C mexFunction arguments:
    MWPOINTER PLHS(*), PRHS(*)
    INTEGER NLHS, NRHS
    mwPointer, external :: mxGetPr, mxGetPi
    mwPointer, external :: mxCreateDoubleMatrix, mxCreateNumericArray
    mwSize, external :: mxGetM, mxGetN
    MWPOINTER YPP 
    mwSize M, N
    integer*4 ComplexFlag
    REAL *8 RYPP(1)
    RYPP(1) = 10
    M = 1
    N = 1
    ComplexFlag = 0
    PLHS(1) = mxCreateDoubleMatrix( M, N, ComplexFlag )
    YPP = MXGETPR(PLHS(1))
    CALL MXCOPYREAL8TOPTR(RYPP, YPP, M*N)
    RETURN
    END

Best Answer

Related Solutions

MATLAB: C-Mex Error: expected “…” or “,”

MATLAB: Building Mex file with Fortan

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