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-239AA6F5-30CE-5FF0-9C36-93D39FECE1DD" xml:lang="en"><title>How

    13 to switch heaps</title><shortdesc>After a call to <codeph>User::SwitchHeap()</codeph>, any new request

    14 for memory is satisfied from the new heap.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    15 <p>A thread can switch between heaps using <codeph>User::SwitchHeap()</codeph>. </p>

    16 <p>After a call to this function, any new request for memory is satisfied

    17 from the new heap.</p>

    18 <p>When freeing memory, it is <b>extremely important</b> that the current

    19 heap is the heap from which it was allocated. Trying to free a memory cell

    20 from a heap when it was allocated from a different heap has undefined consequences.</p>

    21 <codeblock id="GUID-8265D4CF-CDCE-51EF-AC31-765830961D8E" xml:space="preserve">Thing* mything = new Thing;                // Allocate on current heap

    22 RHeap* oldHeap = User::SwitchHeap(newHeap);// Change heaps

    23 ...                                        // Use new heap

    24 User::SwitchHeap(oldHeap);                 // Change to old heap

    25 delete mything;                            // before deleting.</codeblock>

    26 </conbody></concept>