Building Mex file with Fortan

I am trying to understand how to build mex files. I made following test code It compiles using the Visual Fortran Compiler 2011 but when i try to call it matlab shuts down with the message segmentation violation detected. Does anyone sees what goes wrong?

if true
  #include <fintrf.h>
C
C Gateway routine
C
    SUBROUTINE MEXFUNCTION(NLHS, PLHS, NRHS, PRHS)
C mexFunction arguments:
    MWPOINTER PLHS(*), PRHS(*)
    MWPOINTER NLHS, NRHS
   mwPointer mxGetPr,mxGetPi
   mwPointer mxCreateDoubleMatrix,mxCreateNumericArray
   mwSize mxGetM, mxGetN

       MWPOINTER YPP 
       REAL *8 RYPP(1)

       YPP = MXGETPR(PLHS(1))
       RYPP(1) = 10

       CALL MXCOPYREAL8TOPTR(RYPP, YPP, 1)

      RETURN
      END

end

Answer 1

[James Tursa]

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