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<span id="Cell-Arrays-with-Mex_002dFiles"></span><div class="header">
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<span id="Cell-Arrays-with-Mex_002dFiles-1"></span><h4 class="subsection">A.2.4 Cell Arrays with Mex-Files</h4>
<p>One can perform exactly the same operations on Cell arrays in mex-files as in
oct-files. An example that duplicates the function of the <samp>celldemo.cc</samp>
oct-file in a mex-file is given by <samp>mycell.c</samp> as shown below.
</p>
<div class="example">
<pre class="verbatim">#include "mex.h"
void
mexFunction (int nlhs, mxArray *plhs[],
int nrhs, const mxArray *prhs[])
{
mwSize n;
mwIndex i;
if (nrhs != 1 || ! mxIsCell (prhs[0]))
mexErrMsgTxt ("ARG1 must be a cell");
n = mxGetNumberOfElements (prhs[0]);
n = (n > nlhs ? nlhs : n);
for (i = 0; i < n; i++)
plhs[i] = mxDuplicateArray (mxGetCell (prhs[0], i));
}
</pre></div>
<p>The output is identical to the oct-file version as well.
</p>
<div class="example">
<pre class="example">[b1, b2, b3] = mycell ({1, [1, 2], "test"})
⇒
b1 = 1
b2 =
1 2
b3 = test
</pre></div>
<p>Note in the example the use of the <code>mxDuplicateArray</code> function. This is
needed as the <code>mxArray</code> pointer returned by <code>mxGetCell</code> might be
deallocated. The inverse function to <code>mxGetCell</code>, used for setting Cell
values, is <code>mxSetCell</code> and is defined as
</p>
<div class="example">
<pre class="example">void mxSetCell (mxArray *ptr, int idx, mxArray *val);
</pre></div>
<p>Finally, to create a cell array or matrix, the appropriate functions are
</p>
<div class="example">
<pre class="example">mxArray *mxCreateCellArray (int ndims, const int *dims);
mxArray *mxCreateCellMatrix (int m, int n);
</pre></div>
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