Passing different data type between various mex functions from within matlab

Suppose I want to pass a pointer to different data type to pass between various functions in Matlab, can I do it?

For e.g: Suppose the library in C I use two structure pointers "ghkModel* m" and "ghkData* d". These are library specific data types. These are two large structures that contains various fields. I need to preserve the content of ghkData *d since it is used later by varous functions.

Is there a way to do this:

For example, this is what I want to do:

myMatlabFunction()

[m, d] = C_mex_funtion_1(); % m and d contains the structure ghkModel and ghkData
[p, q] = C_mex_function_2(m,d);
rslt = C_mex_function_3(p,q, m,d);

end

Basically question is how to pass in data that is not of type mxArray to other mex functions within matlab code?

And how to allocate memory to it? I mean in the mex entry point.

void mexFunction( int nlhs, mxArray *plhs[],
                  int nrhs, const mxArray *prhs[])
{
    ghkModel* m = mxGetPr(prhs[0]);
    ghkData* d = mxGetPr(prhs[1]);
    callSomeFunction(m,d);
}
Any helpful suggestion is appreciated.

[James Tursa]

Are the mex functions written by you? I.e., do you have the source code for them and can modify them?