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<chapter id="libpq-chapter">

int PQflush(PGconn *conn);

</synopsis>

<function>PQflush</function> needs to be called on a non-blocking connection

before calling <function>select</function> to determine if aresponce has

before calling <function>select</function> to determine if aresponse has

arrived. If 0 is returned it ensures that there is no data queued to the

backend that has not actually been sent. Only applications that have used

<function>PQsetnonblocking</function> have a need for this.