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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-3313A7E0-B10A-5CDE-8DA3-FB9C48FC80CA" xml:lang="en"><title>Change

    13 notifier</title><shortdesc>Describes change notifiers and what they are used for.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    14 <p>Change notifiers allow threads to be notified of changes in the environment

    15 such as a switch in locale, crossing over past midnight etc.; the <codeph>TChanges</codeph> enumerator

    16 lists the possible events.</p>

    17 <p>A change notifier is a Kernel object and, as such, is managed by the Kernel.

    18 Access to a change notifier is through an <codeph>RChangeNotifier</codeph> handle.</p>

    19 <p>The list of possible events is itemised by the enumerators of the <codeph>TChanges</codeph> enum.</p>

    20 <p>The change notifier service is not used directly but is an asynchronous

    21 service provider intended to be part of an active object. For example, the

    22 Environment Change Notifier API provides a <codeph>CEnvironmentChangeNotifier</codeph> active

    23 object which uses the services of the change notifier as part of its implementation.</p>

    24 </conbody></concept>