1 <?xml version="1.0" encoding="utf-8"?>

     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

     3 <!-- This component and the accompanying materials are made available under the terms of the License 

     4 "Eclipse Public License v1.0" which accompanies this distribution, 

     5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

     6 <!-- Initial Contributors:

     7     Nokia Corporation - initial contribution.

     8 Contributors: 

     9 -->

    10 <!DOCTYPE concept

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

    12 <concept id="GUID-485B1284-9DB0-5AF7-906A-89A830B9FE44" xml:lang="en"><title>Handles

    13 Overview</title><shortdesc>This document provides an overview of handles.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    14 <section id="GUID-115D8AE7-F04D-47DE-83B4-0F651D721006"><title>Purpose</title> <p>Allows

    15 a thread or process to identify an object which is owned or managed by another

    16 thread or process. Handles allow a client to access, or refer to, Kernel objects.</p> </section>

    17 <section id="GUID-245AC90F-A46C-488E-B4FE-435F93851682"><title>Architectural

    18 relationships</title> <p>All handles are instances of classes derived from <codeph>RHandleBase</codeph>.

    19 Interactions between the holder of a handle and the object which the handle

    20 represents are mediated through the Kernel. Handles are also used in client-server

    21 relations; the client side refers to a server side session through a handle,

    22 an<codeph>RSessionBase</codeph> object.</p> </section>

    23 <section id="GUID-DCBCFDE8-F8BA-455A-8918-0EC26EADE2C8"><title>Description</title> <p>The

    24 handle class, <xref href="GUID-727D2B62-09A9-3CBC-AB6F-591E52EC68EB.dita"><apiname>RHandleBase</apiname></xref>, encapsulates the basic behavior

    25 common to all handles; for example, <codeph>Close()</codeph> to close a handle.

    26 In particular, the class hides the handle-number which identifies the object

    27 which the handle represents.</p> <p>The class is abstract in the sense that

    28 a <codeph>RHandleBase</codeph> object is never explicitly instantiated. It

    29 is always a base class to a concrete handle class; for example, <codeph>RSemaphore</codeph>, <codeph>RMutex</codeph>, <codeph>RThread</codeph> etc.</p> </section>

    30 <section id="GUID-9ABD8697-9E59-44D6-8F2C-4D73A3EF15E9"><title>See also</title> <p><xref href="GUID-BE0C94BE-94F0-54B3-8674-366C09261E5D.dita">Reference Counting Objects

    31 Overview</xref> </p> <p><xref href="GUID-5D4B86D3-20C4-5D87-A6C1-225018D32347.dita">Threads

    32 and Process Management Overview</xref> </p> <p><xref href="GUID-D0D27AEA-FDDB-5F6F-94F6-ADDF5910DC47.dita">Client/Server

    33 Overview</xref> </p> </section>

    34 </conbody></concept>