How can I pass structures to a mex-file?

Hello everyone,

I am trying to compile a C code in MATLAB, I have been reading through a bunch of tutorial and questions about this topic in the last 4 days and I did not understand it at all yet.

Let me explain my problem, I have this structure here.

typedef struct _BoardDef
{
    U32 RecordCount;
    U32 RecLength;
    U32 PreDepth;
    U32 ClockSource;
    U32 ClockEdge;
    U32 SampleRate;
    U32 CouplingChanA;
    U32 InputRangeChanA;
    U32 InputImpedChanA;
    U32 CouplingChanB;
    U32 InputRangeChanB;
    U32 InputImpedChanB;
    U32 TriEngOperation;
    U32 TriggerEngine1;
    U32 TrigEngSource1;
    U32 TrigEngSlope1;
    U32 TrigEngLevel1;
    U32 TriggerEngine2;
    U32 TrigEngSource2;
    U32 TrigEngSlope2;
    U32 TrigEngLevel2;
}BoardDef, *pBoardDef;

Where U32 is defined as below

typedef unsigned long    U32

I want to create the mex file to the the function used below

status = AlazarSetRecordCount( h, bd.RecordCount);

Where bd is defines as below

BoardDef bd;

The problem is, I don`t know how to handle the structure thing in the mex file, I have read through the example phonebook.c example but it did not clarify me that much.

I doing as follow:

#include "mex.h"
#include <AlazarApi.h>
#include <AlazarError.h>
#include <AlazarCmd.h>

void mexFunction( int nlhs, mxArray *plhs[],
                  int nrhs, const mxArray *prhs[] )
{
  double *x0,*y0,*y1;
  RETURN_CODE status;
  U32 RecordCount;
  int handle;
  mwSize mrows,ncols;
  mxArray *rc; //RecordCount

    /* Create matrix for the return argument. */
    plhs[0] = mxCreateDoubleMatrix(1,1, mxREAL);
    plhs[1] = mxCreateDoubleMatrix(1,1, mxREAL);

    /* Assign pointers to each input and output. */
    x0 = mxGetPr(prhs[0]);
    y0 = mxGetPr(plhs[0]);
    y1 = mxGetPr(plhs[1]);

    /* Call the timestwo subroutine. */
    handle = (int)x0[0];
    status = AlazarSetRecordCount( handle, RecordCount);
    *y0 = status;
    *y1 = *rc;
  }

I know that I have some mistakes in that code, for example in the last line I am assigning rc to y1 but I have nothing in rc yet because I don`t know where I have to create the structure in the mexfile, but I know that to access a filed of the structure I use mxGetField.

So my question is, where do I declare my whole structure and how do I pass it as a parameter of the function AlazarSetRecordCount?

All help is welcome guyz. Thank you.

[James Tursa]

Are you trying to pass a MATLAB structure into a mex routine, then convert it to the C struct you show above, then pass that along to a C function, then return something back to MATLAB?

[Abigail Cember]

I don't know if that's what Kaio was trying to do, but that's what I'm trying to do -- can you explain how to do it?

[Jan]

@Abigail: Sorry, what are you trying to do? Is this a new question? Then please open a new thread.

Answer 1

[Kaio]

No one knows anything about it? ANY help is welcome, really any help.