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<concept id="GUID-2B7F7484-3A44-4A96-9B5D-79DF8A09115A" xml:lang="en"><title>How resource

files work</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>In the Symbian platform, <xref href="GUID-5F749184-C804-41FC-BA81-038783BDC967.dita">resource</xref> files

are used to define UI components used in applications. The UI components consist

of data structures that are defined in resource files, and then are loaded

by the classes controlling the UI implementation. When UI component implementation

is split into these two approaches, it means that resources can be recompiled,

for example for new languages, without having to recompile the application

code (unless you change the resource identifiers).</p>

<p>The following resource files are typically used as source files in Symbian

applications:</p>

<ul>

<li><p><codeph>.rss</codeph> – resource source files used for UI

components in the application. For more information, see <xref href="GUID-EC49B54F-7724-433B-BD7F-201DE3B7DAA6.dita">Resource

file structure</xref>, <xref href="GUID-23A60DE7-B72D-41BD-9F1E-882D31A7E3C7.dita">Required

resource file statements</xref>, and <xref href="GUID-2C74E932-B1CA-434B-AF96-66D52D689620.dita">Optional

resource file statements</xref>.</p>

</li>

<li><p><codeph>_reg.rss</codeph> – resource source file used for

registration. For more information, see <xref href="GUID-BF1AAA0D-DF2F-4E1D-A0D2-F419BD32F97A.dita">Creating

registration resource files</xref>.</p>

</li>

<li><p><codeph>.hrh</codeph> – resource header file used to define

enumerated sets of values. For more information, see <xref href="GUID-D52E98C3-F5EE-4CE1-A4F5-2EF41A066B8A.dita">Creating

resource header files</xref>.</p>

</li>

<li><p><codeph>.rls</codeph> – localisation files used as a source

for UI texts strings in applications, and for managing these texts. For more

information, see <xref href="GUID-E111C4E8-1342-4E87-ACB4-5B630AF1501C.dita">Internationalization

and localization</xref>.</p>

</li>

</ul>

<p>The structures and symbolic IDs of these files are used in various ways

in your code.</p>

<p> The resource files above are then compiled to yield the following files:</p>

<ul>

<li><p><codeph>.rsc</codeph> or <parmname>rNN</parmname>, where

NN is a two number Symbian locale ID - compiled, machine-readable resource

files used by the application</p>

<itemgroup/>

</li>

<li><p><codeph>.rsg</codeph> - generated resource header file containing

the symbolic IDs of the resources for inclusion into your code</p></li>

<li><p><codeph> _reg.rsc</codeph> or <parmname>_reg.rNN</parmname>,

where NN is a two number Symbian locale ID - compiled, machine-readable resource

file used for registration </p></li>

</ul>

<p>The <parmname>rsc</parmname>, <parmname>rNN</parmname>, and <parmname>_reg.rsc</parmname> files

need to be included in your <parmname>sis</parmname> <xref href="GUID-61EE2BE0-7B86-42CD-A03F-857DD8FAC246.dita">installation

file</xref> so that they are placed in the device when the application is <xref href="GUID-3BB12D99-8CD7-47B0-A788-C85EF206806C.dita">installed</xref>.</p>

<p>When the application framework launches an application, it loads the

application resource file. The application framework compares the system locale

language setting with the available resource files, and loads the resource

file whose extension matches the locale language code. If there is no match,

then the system loads the resource file with the extension <parmname>rsc</parmname>.</p>

</conbody></concept>