Basic -Types Overview

Purpose

Provides implementation-independent versions -of the C++ built-in types, defines the Symbian platform standard base class -for all heap-allocated classes, and provides some useful yet simple global -functions.

You should avoid using the C++ built-in types directly: -always use the Symbian platform types instead.

Description

The API defines classes and typedefs -for integer, text, Boolean, and floating point types. Additionally, a utility -class to help with reference arguments in variable argument functions is provided.

Heap-allocated classes base

Symbian platform requires that -all classes that own dynamically allocated resources derive from a standard -base class, CBase. Such classes by conventions have a C -prefix to their name, and so are referred to as C classes. C classes, and -their associated allocation and cleanup idioms, are fundamental to Symbian -platform.

Integral -types

TInt is the natural machine word integer -and should be used in all general contexts where integer arithmetic is desired.

TInt32, TInt16 and TInt8 map onto C++ built-in types in most implementations. These -types should only be used where the size of the integer is of first importance.

TUint is -an unsigned integer of the natural machine word size. It should be used for -flag and handle words, which are manipulated using bitwise and equality-comparison -operations rather than arithmetic.

TUint32, TUint16 and TUint8 are -available where the specific representation width is important.

Text types

TText represents a character -in the natural width for the Symbian platform build. From v5.1 onwards, this -is 16 bits.

TText8 is available for build-independent -8-bit characters, and TText16 for build-independent 16-bit -characters.

The TChar class wraps a character value -and provides a number of utility functions to operate upon it.

Boolean type

TBool represents a Boolean -whose value may be true or false. It is implemented as a natural machine-word -integer.

Floating-point -types

TReal is a 64-bit double-precision type, -used as the argument type for all math functions, and the default type of -floating-point literals.

TReal64 and TReal32 are -available when the precise size is important.

Value reference type

The value reference type is a utility -that is provided to overcome problems with specifying a C++ reference argument -before the ellipsis argument in variable argument functions.

The value -reference type is provided by TRefByValue <T>.

Global functions

Max(), Min(), Rng() and Abs() are simple global -functions that are useful in many contexts.