opaque handle that can subsequently be passed to

<function>GetBackgroundWorkerPid(<parameter>BackgroundWorkerHandle *</parameter>, <parameter>pid_t *</parameter>)</function> or

<function>TerminateBackgroundWorker(<parameter>BackgroundWorkerHandle *</parameter>)</function>.

<function>GetBackgroundWorker</> can be used to poll the status of the

<function>GetBackgroundWorkerPid</> can be used to poll the status of the

worker: a return value of <literal>BGWH_NOT_YET_STARTED</> indicates that

the worker has not yet been started by the postmaster;

<literal>BGWH_STOPPED</literal> indicates that it has been started but is