--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-B1C0C5E2-DC8D-5230-8D4B-338DF619F1D2.dita	Thu Jan 21 18:18:20 2010 +0000
@@ -0,0 +1,12 @@
+<?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 concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept xml:lang="en" id="GUID-B1C0C5E2-DC8D-5230-8D4B-338DF619F1D2"><title>Critical Sections Overview</title><prolog><metadata><keywords/></metadata></prolog><conbody><section><title>Purpose</title> <p>Synchronises exclusive access to shared resources within a single process. </p> </section> <section><title>Description</title> <p>Critical sections are typically used to serialize access to a section of re-entrant code that cannot be executed concurrently by more than one thread within a process. A critical section object only allows one thread into a controlled section, forcing other threads which attempt to gain access to that critical section to wait until the first thread has exited from that section.</p> <p>A critical section <i>cannot</i> be used to control access to a resource shared by threads across different processes. For that, use a mutex.</p> <p>Critical sections are Kernel objects and, as such, are managed by the Kernel, and accessed by user programs through handles. They are implemented using a semaphore. </p> <p>The critical section handle is provided by <xref href="GUID-FC5F1EC1-28CC-3B06-83C4-B90EF8EEBA07.dita"><apiname>RCriticalSection</apiname></xref>.</p> </section> </conbody></concept>
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