Key type

This document describes the types of keys available.

Keys can be one of three types, selected by choosing the appropriate constructor:

  • Descriptor type

  • Text type

  • Numeric type

Descriptor type

The key is defined to be a descriptor, i.e. an object derived from TDesC . In practice, a descriptor key within an array element is one of the types: TPtrC , TPtr , TBufC or TBuf (but not an HBufC ).

For a Unicode build, they are defined as TDesc16 , TPtrC16 , TPtr16 , TBufC16 and TBuf16 respectively, while for a non-Unicode build, they are defined as TDesc8 TPtrC8 , TPtr8 , TBufC8 and TBuf8 respectively.

Text type

The key is defined to be of type TText . For a Unicode build, TText is defined as TText16 while for a non-Unicode build, it is defined as TText8 .

Numeric type

The key is defined to be of type: TInt , TInt8 , TInt16 , TInt32 , TInt64 , TUint , TUint8 , TUint16 or TUint32 .