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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 id="GUID-716F1987-F1F1-4E20-8390-BBD9AE592C2A"><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 id="GUID-CA323EF2-3A8A-4363-AC6E-A21B3C2648D7"><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 device. </p> </section>
<section id="GUID-1C59222F-2F39-4599-8052-AE7C83854AC8"><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 id="GUID-7A7C9409-D701-4C64-B0B2-AE0F89C396FA"><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 id="GUID-8B18A01A-44D4-400E-9CEC-3E75F55D7F7F"><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>