<para>

Background workers can be initialized at the time that

<productname>PostgreSQL</> is started including the module name in

<productname>PostgreSQL</> is startedbyincluding the module name in

<varname>shared_preload_libraries</>. A module wishing to run a background

worker can register it by calling

<function>RegisterBackgroundWorker(<type>BackgroundWorker *worker</type>)</function>

When a background worker is registered using the

<function>RegisterDynamicBackgroundWorker</function> function, it is

possible for the backend performing the registration to obtain information

the status of the worker. Backends wishing to do this should pass the

address of a <type>BackgroundWorkerHandle *</type> as the second argument

to <function>RegisterDynamicBackgroundWorker</function>. If the worker

is successfully registered, this pointer will be initialized with an

regardingthe status of the worker. Backends wishing to do this should

pass theaddress of a <type>BackgroundWorkerHandle *</type> as the second

argumentto <function>RegisterDynamicBackgroundWorker</function>. If the

workeris successfully registered, this pointer will be initialized with an

opaque handle that can subsequently be passed to

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

This function can be used to poll the status of the worker: a return