User manual

216
mikoBasic PRO for dsPIC30/33 and PIC24
MikroElektronika
Typedef Specier
The specier typedef introduces a synonym for a specied type. The typedef declarations are used to construct
shorter or more convenient names for types already dened by the language or declared by the user.
The specier typedef stands rst in the declaration:
typedef synonym as <type_denition>
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 mikroBasic PRO for dsPIC.
For example:
‘ Let’s declare a synonym for “word”
typedef Distance as word
‘ Now, synonym “Distance” can be used as type identier:
dim i as Distance ‘ declare variable i of word
In the typedef declaration, as in any other declaration, several types can be declared at once. For example:
typedef ^Pti, Array[10] as byte
Here, Pti is a synonym for type “pointer to int”, and Array is a synonym for type “array of 10 byte elements”.
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 qualier const implies that a declared object will not change its value during runtime. In declarations with the
const qualier all objects need to be initialized.
The mikroBasic 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 PI as byte = 3.14159