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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> </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>