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<concept id="GUID-DCA2880E-7DF9-5E60-8F87-241711935389" xml:lang="en"><title>FeatMngrExample:

dynamic feature management example</title><shortdesc>This example demonstrates the use of Feature Manager APIs for dynamic

feature management. It also demonstrates how to receive notification about

changes to a feature. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<section><title>Download</title> <p>Click on the following link to download

the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-3bc38b8f-c8bf-4af9-969b-a0bc4dd4dcad.zip" scope="external">FeatMngrExample.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-3bc38b8f-c8bf-4af9-969b-a0bc4dd4dcad.html" scope="peer">browse</xref> to view the example code.</p> </section>

<section><title>Purpose</title> <p>The example shows how to use the <xref href="GUID-0CA63AEB-9A80-51C6-AE7F-E747D6B3B789.dita">Feature Manager</xref> API.

UI vendors and device manufacturers can use this API to declare features (such

as DRM agents, codecs, vibra) as available or not. The feature set can be

adjusted dynamically as software services are installed and uninstalled or

as platform capabilities are discovered dynamically. </p> <p>This example

shows how Feature Manager APIs allow applications and system software to establish

which features are present on or absent from a Symbian OS device. </p> </section>

<section><title>Design and implementation</title> <p>The example consists

of two processes: </p> <ul>

<li id="GUID-0DA213CD-55C2-5ADD-A872-20D008EE5D46"><p> <filepath>featmngrexample.exe</filepath>:

this is the main process which provides the list of available features. It

also provides the option to add new features or delete/update a feature. </p> </li>

<li id="GUID-B2A151CA-3807-5990-B431-CF4083E42107"><p> <filepath>featurechecker.exe</filepath>:

this process receives notification about new features installed or uninstalled

by the main process. </p> </li>

</ul> <p><b>FeatMngrExample</b> </p> <p>This shows the use of the <xref href="GUID-F6AAAC24-4A62-383A-86C6-2E46335C3FD4.dita"><apiname>RFeatureControl</apiname></xref> API

to manage features. </p> <p>It presents menu options to the user to list the

available features, to add or delete a feature, update an existing feature,

and to enable or disable a feature. It also starts another process, called

featurechecker.exe which receives notifications of events happening in this

process. The list of features includes some whose feature flags are non-modifiable.

Any attempt to modify or delete those features will result in a system error

-21 (<codeph>KErrAccessDenied</codeph>). When adding a new feature, it should

be in the range as described in the console because the featurechecker process

subscribes to this range of features for change notification. </p> <p><b>FeatureChecker</b> </p> <p>This

process is started by <filepath>featmngrexample.exe</filepath>. It implements

the <xref href="GUID-623C4183-00F0-36B0-AE1F-5C5EDCAF1B3D.dita"><apiname>MFeatureObserver</apiname></xref> class to handle notification of feature

changes. <codeph>FeatureChecker</codeph> also demonstrates the use of the <xref href="GUID-CA12C6F7-E997-33B8-9463-B326BC1832C5.dita"><apiname>CFeatureNotifier</apiname></xref> class.

It implements <codeph>HandleNotifyChange()</codeph> to handle the changes

made by FeatMngrExample. The type of change is displayed to the user as an

infoprint message (<xref href="GUID-C197C9A7-EA05-3F24-9854-542E984C612D.dita#GUID-C197C9A7-EA05-3F24-9854-542E984C612D/GUID-EEF84AA0-A277-390D-BFAB-CF50C94DF18D"><apiname>User::InfoPrint()</apiname></xref>). <codeph>HandleNotifyChange()</codeph> is

called to handle changes for those features which are subscribed to for notification

(in the <codeph>NotifyFeatureL</codeph> () method). </p> </section>

<section><title>Building and configuring</title> <p>To build the example: </p> <ul>

<li id="GUID-A8030260-4FEF-55E1-A50C-65BEE3F08E21"><p>The example builds two

executables called <filepath>featmngrexample.exe</filepath> and <filepath>featurechecker.exe</filepath> in

the standard locations. The second executable is run by the first. </p> </li>

<li id="GUID-DD5D4965-A174-553C-BD13-22A6DFE9E52F"><p>You can build the example

from your IDE or the command line. </p> <p>If you use an IDE, import the <filepath>bld.inf</filepath> file

of the example into your IDE, and use the build command of the IDE. </p> <p>If

you use the command line, open a command prompt, and set the current directory

to the source code directory of the example. You can then build the example

with the SBSv1 build tools with the following commands: </p> <p><userinput>bldmake

bldfiles</userinput> </p> <p><userinput>abld build</userinput> </p> <p><xref href="GUID-793A5EF9-CC16-5EEB-9011-6431EA76EB15.dita">How to use bldmake</xref> and <xref href="GUID-B6B54E07-3B34-5D5C-8815-93383FA8FB4B.dita">How to use abld</xref> describe

how to use the SBSv1 build tools. </p> </li>

</ul> </section>

<section><title>Running the example</title> <p>When running the example, the

user is presented with various menu options that are self-explanatory. Press

any other key to exit. </p> </section>

<section id="GUID-433F7103-5372-5971-85A6-0FBF88ECE5C1"><title>See also:</title><p><xref href="GUID-7495B1C8-38B5-5A09-8231-25B3BBC09F51.dita">Feature Management</xref></p></section>

</conbody></concept>