--- a/Symbian3/PDK/Source/GUID-B97BAC2E-04E3-4979-BACE-9C46BADE912E.dita	Thu Mar 11 15:24:26 2010 +0000
+++ b/Symbian3/PDK/Source/GUID-B97BAC2E-04E3-4979-BACE-9C46BADE912E.dita	Thu Mar 11 18:02:22 2010 +0000
@@ -1,71 +1,71 @@
-<?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 id="GUID-B97BAC2E-04E3-4979-BACE-9C46BADE912E" xml:lang="en"><title>Deferred
-Function Calls</title><shortdesc>This document describes how Deferred Function Calls are used to
-implement asynchronous requests.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
-<section id="GUID-1F20014A-5F1E-48B3-AEB8-ED1922452A84">   
-   <title>Deferred function calls</title> <p>Asynchronous request processing
-is normally done in a Deferred Function Call (DFC). The second stage of interrupt
-handling is deferred to run as a DFC, which runs in a non-critical context. </p> <p>Different
-asynchronous requests can be handled using a single or multiple DFCs. The
-number of DFCs to be created must be decided when the driver is designed.
-For example, a driver that handles at a time an asynchronous receive request
-and a transmit request would create two DFCs each for receive and transmit. </p> 
-   </section>
-<section id="GUID-5439E26D-754A-46F3-B607-D229BF5B8A8C"><title>Creation</title> <p>DFCs
-are created using <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita"><apiname>TDfc</apiname></xref> objects. </p> <p>The DFC is initialised
-with a DFC callback function, a pointer to an object to be passed to the callback
-function, and a priority. It can also provide the DFC queue to be used by
-this DFC at the time of construction. </p> <codeblock id="GUID-B3918CAB-F168-5992-BFA9-868648D07083" xml:space="preserve">TDfc iRxDfc;
-iRxDfc(RxDataDfc,this,1); 
-    or
-iRxDfc(RxDataDfc,this,iDfcQ,1);</codeblock></section>
-<section id="GUID-886457DF-0DB5-4447-BC9B-EB43060A5C6B"><title>Queuing</title> <p>To
-initiate the process of DFC functionality, the DFC object must be queued to
-the DFC queue associated with the Kernel thread. </p> <p>Before adding the
-DFC to a DFC queue of the thread, it must be associated with the queue (<xref href="GUID-24B2FEDB-9273-351F-A1C6-6F5F91BF83B7.dita"><apiname>TDfcQue</apiname></xref>)
-object. This can be either done at the time of construction, or can be set
-later, by calling <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-E3458CD4-7A1C-3FBD-A7FB-488A9C92AE42"><apiname>TDfc::SetDfcQ()</apiname></xref>. </p> <codeblock id="GUID-B57B1C37-A1A5-5C85-AED8-FDD8DBE84280" xml:space="preserve">...
-// Associate the Tx and Rx DFCs with the same queue set to receive 
-// the client messages for this driver. SetDfcQ() sets up the DFC 
-// queue for the DFCs constructed for Tx and Rx
-//
-iRxDfc.SetDfcQ(iDfcQ);
-...</codeblock> <p> <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-18073EBB-D91B-3AC8-87A2-424AEDD4D7A4"><apiname> TDfc::Add()</apiname></xref> or <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-F6F0C858-8EB2-387B-AE1A-F04B51CE4CED"><apiname>TDfc::Enque()</apiname></xref> is
-used to add the DFC object to the DFC queue. From an ISR, <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-18073EBB-D91B-3AC8-87A2-424AEDD4D7A4"><apiname>TDfc::Add()</apiname></xref> is
-used. From a thread, <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-F6F0C858-8EB2-387B-AE1A-F04B51CE4CED"><apiname>TDfc::Enque()</apiname></xref> is used. If preemption
-is disabled, <codeph>TDfc::Add()</codeph> could also be used. </p> <codeblock id="GUID-9FBB6881-4BA9-534E-86C7-3A0167E9159C" xml:space="preserve">// TDfc::Add() will queue an IDFC or a DFC from an ISR. This function 
-// is the only way to queue an IDFC and is the only way to queue a 
-// DFC from an ISR. To queue a DFC from an IDFC or a thread either 
-// TDfc::Enque() or TDfc::DoEnque() should be used. This function 
-// does nothing if the IDFC/DFC is already queued.
-//
-iRxDfc.Add();
-</codeblock></section>
-<section id="GUID-E0B9073A-1554-4085-BE24-E27633B7EDF2"><title>Callback function</title> <p>The
-DFC callback function is a static function called when a DFC is executed.
-A pointer to this function is provided at the time of DFC object creation.
-This function implements the deferred functionality of an asynchronous request,
-such as reading or writing data from or to an I/O peripheral. It would then
-either complete the request or start another operation. </p> <codeblock id="GUID-5682EDE1-8397-592D-82CE-78DF11487512" xml:space="preserve">static void RxDataDfc(TAny* aPtr);</codeblock></section>
-<section id="GUID-A57C3C99-3032-48CD-A800-E9EE7DCDF4E3"><title>Cancellation</title> <p>A
-DFC function must be cancelled while cleaning up resources, for example, when
-closing the channel. The function <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-9851B90B-8D05-3C86-B083-44C4564AC140"><apiname>TDfc::Cancel()</apiname></xref> cancels
-the DFC if it is already queued. It does nothing if a DFC is not queued. It
-must be called to avoid orphaned DFCs. </p> <codeblock id="GUID-CD926E3D-13E8-51C4-B224-8150FD4D70DB" xml:space="preserve">...
-// If it is a Transmit request, cancel the Transmit DFC. 
-// TDfc::Cancel() cancels the DFC if it is already queued. It 
-// does nothing if DFC is not queued.
-//
-iTxDfc.Cancel();
-...</codeblock></section>
+<?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 id="GUID-B97BAC2E-04E3-4979-BACE-9C46BADE912E" xml:lang="en"><title>Deferred
+Function Calls</title><shortdesc>This document describes how Deferred Function Calls are used to
+implement asynchronous requests.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-1F20014A-5F1E-48B3-AEB8-ED1922452A84">   
+   <title>Deferred function calls</title> <p>Asynchronous request processing
+is normally done in a Deferred Function Call (DFC). The second stage of interrupt
+handling is deferred to run as a DFC, which runs in a non-critical context. </p> <p>Different
+asynchronous requests can be handled using a single or multiple DFCs. The
+number of DFCs to be created must be decided when the driver is designed.
+For example, a driver that handles at a time an asynchronous receive request
+and a transmit request would create two DFCs each for receive and transmit. </p> 
+   </section>
+<section id="GUID-5439E26D-754A-46F3-B607-D229BF5B8A8C"><title>Creation</title> <p>DFCs
+are created using <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita"><apiname>TDfc</apiname></xref> objects. </p> <p>The DFC is initialised
+with a DFC callback function, a pointer to an object to be passed to the callback
+function, and a priority. It can also provide the DFC queue to be used by
+this DFC at the time of construction. </p> <codeblock id="GUID-B3918CAB-F168-5992-BFA9-868648D07083" xml:space="preserve">TDfc iRxDfc;
+iRxDfc(RxDataDfc,this,1); 
+    or
+iRxDfc(RxDataDfc,this,iDfcQ,1);</codeblock></section>
+<section id="GUID-886457DF-0DB5-4447-BC9B-EB43060A5C6B"><title>Queuing</title> <p>To
+initiate the process of DFC functionality, the DFC object must be queued to
+the DFC queue associated with the Kernel thread. </p> <p>Before adding the
+DFC to a DFC queue of the thread, it must be associated with the queue (<xref href="GUID-24B2FEDB-9273-351F-A1C6-6F5F91BF83B7.dita"><apiname>TDfcQue</apiname></xref>)
+object. This can be either done at the time of construction, or can be set
+later, by calling <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-E3458CD4-7A1C-3FBD-A7FB-488A9C92AE42"><apiname>TDfc::SetDfcQ()</apiname></xref>. </p> <codeblock id="GUID-B57B1C37-A1A5-5C85-AED8-FDD8DBE84280" xml:space="preserve">...
+// Associate the Tx and Rx DFCs with the same queue set to receive 
+// the client messages for this driver. SetDfcQ() sets up the DFC 
+// queue for the DFCs constructed for Tx and Rx
+//
+iRxDfc.SetDfcQ(iDfcQ);
+...</codeblock> <p> <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-18073EBB-D91B-3AC8-87A2-424AEDD4D7A4"><apiname> TDfc::Add()</apiname></xref> or <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-F6F0C858-8EB2-387B-AE1A-F04B51CE4CED"><apiname>TDfc::Enque()</apiname></xref> is
+used to add the DFC object to the DFC queue. From an ISR, <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-18073EBB-D91B-3AC8-87A2-424AEDD4D7A4"><apiname>TDfc::Add()</apiname></xref> is
+used. From a thread, <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-F6F0C858-8EB2-387B-AE1A-F04B51CE4CED"><apiname>TDfc::Enque()</apiname></xref> is used. If preemption
+is disabled, <codeph>TDfc::Add()</codeph> could also be used. </p> <codeblock id="GUID-9FBB6881-4BA9-534E-86C7-3A0167E9159C" xml:space="preserve">// TDfc::Add() will queue an IDFC or a DFC from an ISR. This function 
+// is the only way to queue an IDFC and is the only way to queue a 
+// DFC from an ISR. To queue a DFC from an IDFC or a thread either 
+// TDfc::Enque() or TDfc::DoEnque() should be used. This function 
+// does nothing if the IDFC/DFC is already queued.
+//
+iRxDfc.Add();
+</codeblock></section>
+<section id="GUID-E0B9073A-1554-4085-BE24-E27633B7EDF2"><title>Callback function</title> <p>The
+DFC callback function is a static function called when a DFC is executed.
+A pointer to this function is provided at the time of DFC object creation.
+This function implements the deferred functionality of an asynchronous request,
+such as reading or writing data from or to an I/O peripheral. It would then
+either complete the request or start another operation. </p> <codeblock id="GUID-5682EDE1-8397-592D-82CE-78DF11487512" xml:space="preserve">static void RxDataDfc(TAny* aPtr);</codeblock></section>
+<section id="GUID-A57C3C99-3032-48CD-A800-E9EE7DCDF4E3"><title>Cancellation</title> <p>A
+DFC function must be cancelled while cleaning up resources, for example, when
+closing the channel. The function <xref href="GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB.dita#GUID-A14562A5-3E91-3113-AB3C-71DBEA9D58EB/GUID-9851B90B-8D05-3C86-B083-44C4564AC140"><apiname>TDfc::Cancel()</apiname></xref> cancels
+the DFC if it is already queued. It does nothing if a DFC is not queued. It
+must be called to avoid orphaned DFCs. </p> <codeblock id="GUID-CD926E3D-13E8-51C4-B224-8150FD4D70DB" xml:space="preserve">...
+// If it is a Transmit request, cancel the Transmit DFC. 
+// TDfc::Cancel() cancels the DFC if it is already queued. It 
+// does nothing if DFC is not queued.
+//
+iTxDfc.Cancel();
+...</codeblock></section>
 </conbody></concept>
\ No newline at end of file