NULL constant literals

Literal descriptor containing a NULL text string

Three variants are provided and can be used directly:

• KNullDesC16 - the 16 bit variant for Unicode strings

• KNullDesC8 - the 8 bit variant for non-Unicode strings

• KNullDesC - the build independent variant

These are defined in e32std.h and are defined as follows:

• _LIT(KNullDesC,"");

• _LIT8(KNullDesC8,"");

• _LIT16(KNullDesC16,"");