User manual

mikroC PRO for dsPIC
MikroElektronika
229
Type Qualiers
The type qualiers const and volatile are optional in declarations and do not actually affect the type of declared
object.
Qualier const
The const qualier is used to indicate that variable value cannot be changed. Its value is set at initialization.
The mikroC PRO for dsPIC30/33 and PIC24 treats objects declared with the const qualier the same as literals or
preprocessor constants. If the user tries to change an object declared with the const qualier compiler will report an
error.
For example:
const double PI = 3.14159;
Qualier volatile
The volatile qualier indicates that variable values can be changed both with or without user’s interference in the
program. The compiler should not optimize such variable.
Typedef Specier
The typedef declaration introduces a name that, within its scope, becomes a synonym for the specied type. You can
use typedef declarations to construct shorter or more meaningful names for types already dened by the language or
declared by the user.
Typedef names allow you to encapsulate implementation details that may change. Unlike the struct, union, and
enum declarations, the typedef declarations do not introduce new types, but new names for existing types.
The specier typedef stands rst in the declaration:
typedef <type_denition> synonym;
The typedef keyword assigns synonym to <type_denition>. The synonym needs to be a valid identier.
A declaration starting with the typedef specier does not introduce an object or a function of a given type, but rather
a new name for a given type. In other words, the typedef declaration is identical to a “normal” declaration, but instead
of objects, it declares types. It is a common practice to name custom type identiers with starting capital letter — this is
not required by the mikroC PRO for dsPIC30/33 and PIC24.