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<a name="cproj_002c-cprojf_002d_002d_002d-Riemann-sphere-projection"></a>
<h3 class="section">2.17 <code>cproj</code>, <code>cprojf</code>&mdash; Riemann sphere projection</h3>
<a name="index-cproj"></a>
<a name="index-cprojf"></a>
<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;complex.h&gt;
double complex cproj(double complex <var>z</var>);
float complex cprojf(float complex <var>z</var>);

</pre></div>
<p><strong>Description</strong><br>
These functions compute a projection of <var>z</var> onto the Riemann 
sphere: <var>z</var> projects to <var>z</var> except that all complex infinities 
(even those with one infinite part and one NaN part) project 
to positive infinity on the real axis. If <var>z</var> has an infinite part,
then <code>cproj</code>(<var>z</var>) is equivalent to
</p>
<p>INFINITY + I * copysign(0.0, cimag(z))
</p>
<p><code>cprojf</code> is identical to <code>cproj</code>, except that it performs
its calculations on <code>floats complex</code>.
</p>
<br>
<p><strong>Returns</strong><br>
The cproj functions return the value of the projection onto 
the Riemann sphere.
</p>
<br>
<p><strong>Portability</strong><br>
<code>cproj</code> and <code>cprojf</code> are ISO C99
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