--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/PDK/Source/GUID-B9F07057-4B31-5FE8-BE4C-98CC8151CD29.dita	Fri Jan 22 18:26:19 2010 +0000
@@ -0,0 +1,80 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE task
+  PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">
+<task id="GUID-B9F07057-4B31-5FE8-BE4C-98CC8151CD29" xml:lang="en"><title>Single
+Phase Constructor Tutorial</title><shortdesc>Single phase construction is enabled by defining the <apiname>CONSTRUCTORS_MAY_LEAVE()</apiname> macro
+in a public section of a class definition if the single phase construction
+is part of the public interface of the class. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>
+<prereq><p><b>Required background</b></p><p>Before beginning you must know
+the following: </p> <ul>
+<li id="GUID-DC57A39F-122C-545C-A2A1-D26F71209C10"><p> <b>RAII:</b> The Resource
+Acquisition Is Initialization (RAII) idiom is the basis of the implementation
+of the smart pointer class templates. </p> </li>
+<li id="GUID-C0228985-A32D-5652-8CCC-4BF401998FCC"><p> <xref href="GUID-764C2888-7EA7-3F58-B519-878A82E879CA.dita"><apiname>CONSTRUCTORS_MAY_LEAVE()</apiname></xref>:
+This macro is used for enabling single phase construction, particularly for
+CBase-derived classes. </p> </li>
+</ul> </prereq>
+<context><p>Single phase constructor provides a means to use the RAII concepts
+for Symbian Developers who are familiar with C++ standards. It is provided
+as a tool and needs to be used after careful consideration. </p> </context>
+<steps id="GUID-DF51DCE9-ACA3-4376-B4B3-4A31728670D2">
+<step id="GUID-FA70E487-145A-4502-BB58-B09A42F69183"><cmd>Enabling single
+phase constructor</cmd>
+<stepxmp><p>Single phase construction is enabled by defining the CONSTRUCTORS_MAY_LEAVE()
+macro in a public section of a class definition if the single phase construction
+is part of the public interface of the class. An example of this is given
+below: </p><codeblock xml:space="preserve">class CManagedUserSinglePhase : public CBase
+	{
+public:
+	CONSTRUCTORS_MAY_LEAVE
+	static CManagedUserSinglePhase* NewL(CTicker* aTicker)
+		{
+		return new(ELeave) CManagedUserSinglePhase(aTicker);
+		}
+	. . .
+	}	</codeblock></stepxmp>
+</step>
+<step id="GUID-5A449AB7-512E-4701-928A-2209C1A41A06"><cmd>Using single phase
+constructor</cmd>
+<stepxmp><p>This macro must be used within a public section of a class definition,
+if the single phase construction is part of the public interface of the class.
+Other classes, not derived from CBase will not be affected by this macro. </p><p>The
+following example code snippet the class demonstrates the use of an embedded
+string in the ingle-phase construction pattern, where a leave-safe constructor
+fully initializes the object.  </p><codeblock xml:space="preserve">class CStringUserSinglePhase : public CBase
+	{
+public:
+		CONSTRUCTORS_MAY_LEAVE
+
+	static CStringUserSinglePhase* NewL(const TDesC&amp; aName)
+		{
+		return new(ELeave) CStringUserSinglePhase(aName);
+		}
+
+	~CStringUserSinglePhase()
+		{
+		
+		}</codeblock></stepxmp>
+</step>
+<step id="GUID-D41D3443-FBFA-44DA-8E35-E82C12829F3D"><cmd>Need to declare the CONSTRUCTORS_MAY_LEAVE macro</cmd>
+<stepxmp><p>This is necessary because Symbian platform currently lacks the
+placement delete operator counterparts corresponding to the CBase placement
+new operators that take a TLeave parameter (new(ELeave)). The macro defines
+these missing placement delete operators and ensures that all allocated memory
+can be freed if a constructor leaves.</p></stepxmp>
+</step>
+</steps>
+</taskbody><related-links>
+<link href="GUID-B007634D-4D55-528A-8B85-6120C633AC8B.dita"><linktext>EUser High
+Level Library Overview</linktext></link>
+<link href="GUID-96AB1D5A-932E-55BE-A025-F01608546B99.dita"><linktext>RAII Idiom</linktext>
+</link>
+</related-links></task>
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