nt(..., C_SIZE_T)</code>
intrinsic function. e.g. set <code>sz = L * M * N</code> or use
<code>int(L * M * N, C_SIZE_T)</code> for an L&nbsp;&times;&nbsp;M&nbsp;&times;&nbsp;N array.

     <li>Declare a <code>type(C_PTR) :: p</code> to hold the return value from
FFTW's allocation routine.  Set <code>p = fftw_alloc_real(sz)</code> for a real array, or <code>p = fftw_alloc_complex(sz)</code> for a complex array.

     <li><a name="index-c_005ff_005fpointer-566"></a>Associate your pointer <code>arr</code> with