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<concept id="GUID-AB705D21-87A3-5F32-A4B9-17B7593DD5C3" xml:lang="en"><title>UID

Manipulation Overview</title><shortdesc>Describes how globally unique identifiers are manipulated.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<section id="GUID-78302F5A-97C3-4B95-9F72-842D91C2C25C"><title>Purpose</title> <p>To guarantee uniqueness,

all UID values are assigned to developers centrally by Symbian. </p> </section>

<section id="GUID-0600181A-2383-419B-BB57-2833C05F9AE3"><title>Architectural relationships</title> <p>Symbian platform makes

extensive use of UIDs to provide lightweight identification of file types.

This includes both document and executable files. APIs that need to manipulate

files therefore typically use UIDs.</p> </section>

<section id="GUID-B4652BA6-A500-4F3E-9AFF-02C339706B2B"><title>Description</title> <p>The API has two key concepts: UID and

compound identifier. </p> <p><b>UID</b> </p> <p>The

UID is a small wrapper class around a 32-bit value that provides comparison

operators and conversion to text.</p> <p>The UID interface is provided by <xref href="GUID-530281E6-29FC-33F2-BC9B-610FBA389444.dita"><apiname>TUid</apiname></xref>.</p> <p><b>Compound identifier</b> </p> <p>The compound identifier is a group of

up to three UIDs that identify the type of a file. The meaning of the UIDs

varies according to whether the file is a DLL, or document file, etc. </p> <p>The

compound identifier interface is provided by <xref href="GUID-B6D6B0AD-B15C-339A-8540-40540885089A.dita"><apiname>TUidType</apiname></xref>.</p> </section>

<section id="GUID-ECF8B994-B8F0-4EC4-8CE8-06F031541D79"><title>See also</title> <p><xref href="GUID-260C7ACD-0024-59DE-B1C6-0C852E44C457.dita">Dynamically

Loading Link Libraries Overview</xref> </p> <p><xref href="GUID-B69FE02E-3A78-5438-BA7C-F7BB4CD3EB76.dita">File

Server Client Side Overview</xref> </p> <p><xref href="GUID-21CF1D5F-44C5-5407-B3C9-8BC103C97079.dita">File

Stores Overview</xref> </p> </section>