UID Manipulation Overview

Describes how globally unique identifiers are manipulated.


To guarantee uniqueness, all UID values are assigned to developers centrally by Symbian.

Architectural relationships

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.


The API has two key concepts: UID and compound identifier.


The UID is a small wrapper class around a 32-bit value that provides comparison operators and conversion to text.

The UID interface is provided by TUid.

Compound identifier

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.

The compound identifier interface is provided by TUidType.