/p></td>
<td class="parameter_description"><p>a <a class="link" href="cairo-PNG-Support.html#cairo-write-func-t" title="cairo_write_func_t ()"><span class="type">cairo_write_func_t</span></a> to accept the output data, may be <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>
to indicate a no-op <em class="parameter"><code>write_func</code></em>
. With a no-op <em class="parameter"><code>write_func</code></em>
,
the surface may be queried or use