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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-D1C5BB01-6780-41D6-B47B-43D4C983B0B6" xml:lang="en"><title>API Export</title><shortdesc>This document discusses how to export a device driver API.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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13 <p>A driver can export its API to be used by other Kernel code by |
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14 using IMPORT_C in the declaration and EXPORT_C in the definition. |
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15 When the driver is built, these functions are exported to a <filepath>.def</filepath> file. The <filepath>.def</filepath> file is specific |
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16 to the platform to which the driver is built. </p> |
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17 <codeblock id="GUID-3E732A29-D285-5A51-AF25-9B4B06049632" xml:space="preserve">// Kernel extension internal API |
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18 class DExController: public DBase |
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19 { |
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20 … |
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21 void MyExAPI(); |
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22 … |
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23 }; |
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24 |
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25 // Client interface API |
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26 class TExClientInterface |
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27 { |
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28 … |
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29 // static function being exported, this API will go into def file |
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30 // generated while building |
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31 IMPORT_C static void MyExAPI(); |
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32 … |
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33 }; |
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34 |
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35 // Global instance of the object |
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36 DExController *ExController = NULL; |
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37 |
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38 // Implementation of the kernel extension's exported function |
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39 EXPORT_C void TExClientInterface::MyExAPI() |
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40 { |
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41 … |
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42 ExController->MyExAPI(); |
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43 … |
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44 }</codeblock> |
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45 <p>Kernel extensions can also provide information to user programs |
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46 by setting attributes that can be read through the system HAL (Hardware |
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47 Abstration Layer) API. See<xref href="GUID-124AC7EE-E227-5358-A755-628FFE257250.dita"> Handler Implementation</xref> for more information on this. </p> |
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48 </conbody></concept> |