 |
 |
|
 |
 |
84
BasicX Compatibility Note
Structure and Type definitions are not allowed in BasicX compatibility mode.
3.25.1 Structures in Persistent Memory and Program Memory
Structures in Persistent Memory and Program Memory may be defined using the syntax:
{Public | Private | Dim} <name> As Persistent <type>
or
{Public | Private | Dim} <name> As ProgMem <type>
where <type> is the name of a previously defined structure. The allowable members of a Persistent
Memory or Program Memory structure are the intrinsic types Byte, Integer, UnsignedInteger,
Long, UnsignedLong, Single, bounded strings, arrays of those types and other structures containing
only those types. Arrays of structures in Persistent Memory or Program Memory may be defined by
specifying the dimensions in the usual way.
It is permissible to directly assign between any combination RAM-based, Persistent Memory and Program
Memory variables defined using the same structure. Similarly, direct comparison between like structures
(equality and inequality only) is supported.
3.26 Data Type Implementation Information
This section provides more information on the technical details of the fundamental data types and
variants. Although this information is generally not needed to write properly functioning programs it is
provided for those who are interested and for the special cases where knowledge of such implementation
details may help you implement your application.
To review, the table of fundamental data types introduced earlier in this manual is reproduced here with
an additional column indicating the amount of space required for each type.
Fundamental Data Types
Data Type Name
Range of Values
Size in Bytes
Boolean
True, False
1
Byte
0 to 255
1
Integer
-32,768 to 32,767
2
UnsignedInteger
0 to 65,535
2
Long
-2,147,483,648 to 2,147,483,647
4
UnsignedLong
0 to 4,294,967,295
4
Single
approx. ±1.4e-45 to ±3.4e+38
and 0.0
4
String
0 to 255 characters
See 3.26.2
The Boolean type, while occupying an entire byte, will always contain one of two values under normal
circumstances. The value True is represented by the value 255 and the value False by 0. If your
application has a need for a lot of Boolean variables it may be more efficient to use the Bit data type
described in Section 3.22. The primary disadvantage to using the Bit type is that it cannot be passed by
reference.
The Single type is implemented using the data format specified in the IEEE 754 standard for single
precision floating point numbers.
|
 |
|