Memory Leak Likely - Fortran Mex file

I have Matlab code that looks like the following (just part of vey large program) : I have Visual Studio with Windows 10 on my PC

With an explanation afterwards. I am an inexperienced Mex programmer.

Any help would be much appreciated. Thanks and happy holidays!

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function [Solnd,resid,success] = solbvp(glb,Ts,Tt,flg,flg1,alnd,prgin,prgeq,prgbc,lab)
global TTnd Sol0 aa  thtype Vemaxnd Veminnd beta nsf
N = length(TTnd);
success = 1; 
[Solnd, resid] = deal(NaN);
[nstates,dummy] = size(Sol0);
lastwarn('');
warning('off');
if flg1 == 1 
    try
        [Solnd,resid,success]=bvpsolver2(TTnd,Sol0);
    catch ME 
        success = 0;
        fprintf('\n   %s. Singularity                at T_s = %5.1f,    T_t = %5.1f',lab,Ts,Tt)
    end
end
if flg1 == 2
    try
        for i=1:4
            aa_copy(i)=aa(1,i);
        end
        
        aa_copy(5)=0.0;
        aa_copy(6)=0.0;
        aa_copy(7)=0.0;
        
        [Solnd,resid,success]=bvpsolver3(TTnd,Sol0,thtype,aa_copy.',Vemaxnd,Veminnd,nsf);     
    catch ME 
        success = 0;
        fprintf('\n   %s. Bvpsolver 3 error                at T_s = %5.1f,    T_t = %5.1f',lab,Ts,Tt)
    end
end
if flg1 == 3
    try
        for i=1:4
            aa_copy(i)=aa(1,i)
        end
        
        aa_copy(5)=0.0;
        aa_copy(6)=0.0;
        aa_copy(7)=0.0;
        
        [Solnd,resid,success]=bvpsolver3(TTnd,Sol0,thtype,aa_copy.',Vemaxnd,Veminnd,nsf);
        
    catch ME 
        success = 0;
        fprintf('\n   %s. Bvpsolver 3 error                at T_s = %5.1f,    T_t = %5.1f',lab,Ts,Tt)
    end
end
% .... 
%.....(more code) here

end % solbvp

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Most of the function call 'solbvp' is used to compute the solution to a boundary value ordinary differential equation system.

We have replaced the call to the MATLAB built in function BVP5C with a call to two MEX files - bvpsolver2 and bvpsolver3.

Both are intended to solve different sets of BVPs. The code works for first time calls to the mex files (flg1==1 and flg1==2) but MATLAB automatically shuts down for (flg1==3) The second call to bvpsolver3. I think the mex code is okay for bvpsolver2 because I have run it in an extensive loop before. So I only include the mex code for bvpsolver3 below. The code which is for debugging (printing to MATLAB screen) is not in bold. Very important code probably related to the memory leak is in bold.

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Code for Mex file BVPSOLVER3

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#include "fintrf.h"
C======================================================================
#if 0
    C     
    C     bvpsolver3.F
    C     .F file needs to be preprocessed to generate .for equivalent
    C     
    #endif
    C     
    C======================================================================
    C     Gateway routine
    subroutine mexFunction(nlhs, plhs, nrhs, prhs)
    C     Declarations
    implicit none
    C     mexFunction arguments:
    mwPointer plhs(*), prhs(*)
    integer nlhs, nrhs
    integer mxIsNumeric
    C     Function declarations:
    mwPointer mxGetPr
    mwPointer mxCreateNumericArray
    integer*4 mxClassIDFromClassName
    integer*4 classid
    integer*4 complexflag
    mwSize ndim
    mwSize dims(2)
    mwPointer mxCreateDoubleScalar
    mwPointer mxCreateDoubleMatrix
    mwPointer mxGetM, mxGetN
    
    C     Pointers to input/output mxArrays:
    mwPointer T_ptr,YI_ptr, YF_ptr, E_ptr, I_ptr
    mwPointer thtype_ptr,aa_ptr,vemax_ptr,vemin_ptr,nsf_ptr
    
    C     Array information:
    mwPointer mrows, ncols,mrows_aa
    mwSize size
    mwSize rowsize,aa_size
    
    C     Arguments for computational routine:
    real*8  YI_in(3200), T_in(200), E_out, YF_out(3200)
    integer*4 I_out,m_in,n_in
    real*8  aa_in(7),vemax_in,vemin_in,thtype_in_real,nsf_in_real
    integer*4 thtype_in,nsf_in
    
    c--------------------------------------------------------------------------
    character (len=50) :: c
    character (len=50) :: txt     
    C-----------------------------------------------------------------------        
    C     Specify alert to be printed
    write(txt,'(A)') 'Number of inputs (mexPrintf): ' 
    C     Convert nrhs to char
    write(c,'(i1)') nrhs
    C     Call the API
    call mexPrintf(txt)
    call mexPrintf(c)
    C     Check for proper number of arguments. 
    
    if(nrhs.eq.7)then
        call  mexprintf('hello6crud')
        endif
        if(nlhs.eq.3)then
            call mexprintf('hello9crud')
            endif
            mrows_aa=mxGetM(prhs(4))
            if(mrows_aa.eq.4)then
                call mexprintf('hello15')
                endif
                mrows = mxGetM(prhs(2))
                ncols = mxGetN(prhs(2))
                size = mrows*ncols
                rowsize=mrows*1
                aa_size=mrows_aa*1
                if(size.eq.3200)then
                    call mexprintf('hello33')
                    endif
                    if(mrows.eq.16)then
                        call mexprintf('hello36')
                        endif
                        T_ptr = mxGetPr(prhs(1))  
                        YI_ptr = mxGetPr(prhs(2))
                        thtype_ptr = mxGetPr(prhs(3))
                        aa_ptr = mxGetPr(prhs(4))
                        vemax_ptr = mxGetPr(prhs(5))
                        vemin_ptr = mxGetPr(prhs(6))
                        nsf_ptr = mxGetPr(prhs(7))
                        call mxCopyPtrToReal8(T_ptr,T_in,ncols)
                        call mxCopyPtrToReal8(YI_ptr,YI_in,size) 
                        call mxCopyPtrToReal8(aa_ptr,aa_in,7)
                        
                        C      Specify alert to be printed
                        write(txt,'(A)') 'aa_size (mexPrintf): ' 
                        C     Convert nrhs to char
                        write(c,'(i1)')aa_size
                        C     Call the API
                        call mexPrintf(txt)
                        call mexPrintf(c)
                        C      Specify alert to be printed
                        write(txt,'(A)') 'aa_in(1) (mexPrintf): ' 
                        C     Convert nrhs to char
                        write(c,'(f10.4)')aa_in(1)
                        C     Call the API
                        call mexPrintf(txt)
                        call mexPrintf(c)
                        call mxCopyPtrToReal8(vemax_ptr,vemax_in,1)
                        call mxCopyPtrToReal8(vemin_ptr,vemin_in,1)
                        call mxCopyPtrToReal8(thtype_ptr,thtype_in_real,1)
                        thtype_in=int(thtype_in_real)       
                        call mxCopyPtrToReal8(nsf_ptr,nsf_in_real,1)
                        nsf_in=int(nsf_in_real)   
                        plhs(1) = mxCreateDoubleMatrix(mrows,ncols,0)
                        plhs(2) = mxCreateDoubleScalar(1)
                        classid = mxClassIDFromClassName("int32")
                        complexflag = 0
                        ndim = 2
                        dims(1) = 1
                        dims(2) = 1
                        plhs(3) = mxCreateNumericArray(ndim, dims,classid,complexflag)
                        YF_ptr = mxGetPr(plhs(1))
                        E_ptr = mxGetPr(plhs(2))
                        I_ptr = mxGetPr(plhs(3))
                        C      Specify alert to be printed
                        write(txt,'(A)') 'thtype_in (mexPrintf): ' 
                        C     Convert nrhs to char
                        write(c,'(i1)')thtype_in
                        C     Call the API
                        call mexPrintf(txt)
                        call mexPrintf(c)
                        C      Specify alert to be printed
                        write(txt,'(A)') 'nsf_in (mexPrintf): ' 
                        C     Convert nrhs to char
                        write(c,'(i1)')nsf_in
                        C     Call the API
                        call mexPrintf(txt)
                        call mexPrintf(c)
                        C      Specify alert to be printed
                        write(txt,'(A)') 'vemax_in (mexPrintf): ' 
                        C     Convert nrhs to char
                        write(c,'(f10.4)')vemax_in
                        C     Call the API
                        call mexPrintf(txt)
                        call mexPrintf(c)
                        C      Specify alert to be printed
                        write(txt,'(A)') 'vemin_in (mexPrintf): ' 
                        C     Convert nrhs to char
                        write(c,'(f10.4)')vemin_in
                        C     Call the API
                        call mexPrintf(txt)
                        call mexPrintf(c)
                        
                        call bvpsolver3(YF_out,E_out,I_out,T_in,YI_in,
                        +     thtype_in,aa_in,vemax_in,vemin_in,nsf_in)
                        
                        call mxCopyReal8ToPtr(YF_out,YF_ptr,size) 
                        call mxCopyReal8ToPtr(E_out,E_ptr,1)
                        call mxCopyInteger4ToPtr(I_out,I_ptr,1)  
                        return
                    end

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[James Tursa]

Why do you think there is a memory leak? The only dynamic memory allocation I see is from API functions, which should not produce a memory leak because they are garbage collected. MATLAB shutting down is typically the sign of code accessing invalid memory, not a memory leak. You need to examine your data sizes and look for accessing beyond the end of an array, etc.