Accessing matrices stored inside of cell arrays using MEX files in MATLAB <p>I am currently writing a MEX function that will have to work with a cell array in MATLAB. The MEX file is written in C. </p> <p>Essentially, the input to my function will be a cell array where each entry is a numeric matrix with real values. A simple example is:</p> <pre><code>C = cell(1,2); C{1} = ones(10,10); C{2} = zeros(10,4); </code></pre> <p>I would like to be able to access the numeric arrays C{1} and C{2} in my MEX file. Ideally, I would like to do this without having to create a second copy of the data in my MEX File (i.e. get pointers for them).</p> <p>Using the previous example, my current approach is as follows:</p> <pre><code>/* declare a pointer variable to the incoming cell array after it is passed to the MEX function */ mxArray C_CELL = (mxArray *) mxGetData(prhs[0]) /* declare a 2 x 1 array of pointers to access the cell array in C */ double *myarray[2] // /* point towards the contents of C_CELL */ myarray[0] = mxGetPr(C_CELL[0]) myarray[1] = mxGetPr(C_CELL[1]) </code></pre> <p>Unfortunately this seems to yield "invalid use of undefined type 'struct mxArray_tag'" errors.</p>