l <a class="xref" href="libpq-async.html#LIBPQ-PQCONSUMEINPUT"><code class="function">PQconsumeInput</code>
     </a> before calling
       <a class="xref" href="libpq-copy.html#LIBPQ-PQGETCOPYDATA"><code class="function">PQgetCopyData</code></a> again.)  When <em class="parameter"><code>async</code></em> is
       false (zero), <a class="xref" href="libpq-copy.html#LIBPQ-PQGETCOPYDATA"><code class="function">PQgetCopyData</code></a> will block until data is
       available or the operation completes.
    