on).
</p>
<p>In FFTW 3, we have begun recommending that you always declare the type
used to store plans as <code>integer*8</code>.  (Too many people didn&rsquo;t notice
our instruction to switch from <code>integer</code> to <code>integer*8</code> for
64-bit machines.)
</p>
<p>In FFTW 3, we provide a <code>fftw3.f</code> &ldquo;header file&rdquo; to include in
your code (and which is officially installed on Unix systems).  (In FFTW
2, we supplied a <code>fftw_f77.i</code> file, but it was not installed.)
</p