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Generate a constant literal as follows:
_LIT(name, string);
where name
is a C++ variable name and
string
is the literal text enclosed in a pair of double quotes.
All the code fragments use the build independent form but they are equally valid if replaced by the explicit 16 bit variant or the explicit 8 bit variant.
As name
represents a constant variable, it is
conventional for the variable name to start with a capital K
, for
example:
_LIT(KTxtMatchString,"Hello");
This generates the constant literal descriptor:
const static TLitC<5> KTxtMatchString;
and this is initialised to contain the string Hello
.
Developers never need to code a TLitC
class explicitly; it is
always be constructed through the macro.
This constant literal descriptor can be passed directly to functions
which are prototyped to take a const TDesC&
type:
TBufC<32> x;
...
x.Match(KTxtMatchString);
...
The literal descriptor classes: TLitC16
,
TLitC8
, TLitC16
, also provide a conversion operator
so that they can be passed to functions which take a const
TRefByValue<const TDesC>
type. This means that they can be passed
to functions such as TDes::Format()
:
_LIT(KFormat1,"Length is %d");
...
TBuf<256> x;
...
x.Format(KFormat1,8);
...
The &
and the ()
operators acting on a
constant literal return a const TDesC*
and a const
TDesC&
type respectively:
...
_LIT(KTxtMatchString,"Hello");
_LIT(KFormat2,"Text is %S");
...
TInt length;
length = KTxtMatchString().Length();
...
TBuf<256> x;
x.Format(KFormat2,&KTxtMatchString);
...