Symbian OS basic data type

Symbian OS uses object-oriented C + +, but there are some differences from standard C + +. Symbian OS, for example, does not have standard exception handling (Exception) because it does not standardize exception handling when designing Symbian OS. So Symbian designed its own exception handling mechanism: TRAP, leave. The other is the basic type to be spoken today. Symbian basically does not use any standard C + + basic type, and it is well known that different C + + editors have different understanding of the length of int, unsigned int, so tint8,tint16,tint32 is used in Symbian OS.

However, if you do not have a good reason to use a particular length, you should use tint. Many other types also adhere to this principle. For example in the future to speak of TBuf8, TBUF16 can best use for tbuf.

Type	Description
TInt8, TUint8	8-bit integer
TInt16, TUint16	16-bit integer
TInt32, TUint32	32-bit integer
TInt, Tuint	(32-bit) integer
TReal32, TReal64	Real
TText8, TText16	character, equivalent to unsigned char, unsigned short int
Tbool	Boolean
Tany	equivalent to void

Code specification

Symbian OS uses a lot of code specifications that can be used to enhance the readability of symbain code, and some specifications even need to be strictly adhered to, such as the naming of classes:

Kinds	Example	Description
T classes	Tdesc, Tpoint	This class can be used like a basic type because they are usually small and do not use heap so there is no destructor
C classes	Cconsolebase, Cactive	This class is the most used class by Symbian, and C represents their inheritance from the CBase class, and they must have destructors because their objects are created in heap
R classes	Rfile, Rtimer	R represents resources (Resource), they are just a handle to a system resource, they are created on the stack themselves, but the resources they use are created on the heap and need close () after use.
M classes	Meikmenuobserver	This class is an empty interface that needs to inherit from it when used
Static classes	User, Math	This class has only static functions, which are generally library functions.
Structs	Seikcontrolinfo	C-struct

Variable naming

category	example	description
enum	EMONDAY,ETUESDA Y	e represents enumerations
quantitative	kmaxfilename	member Variable	idevice, IX	i represents a member variable
parameter	adevice, AX	a represents the parameter
local variable	device, x< /td>	local variable does not have a fixed specification

In addition, the name of the function, but to talk about the concept of leave before you can understand, so here is not introduced. This lesson is very boring, but clear some concepts, the next lesson we take a closer look at the graphical interface of the HelloWorld.