Structures

Structure <name> [Extends <name>]
  ...
EndStructure 

Structure is useful to define user type, and access some OS memory areas. Structures can be used to enable faster and easier handling of data files. It is very useful as you can group into the same object the informations which are common. Structures fields are accessed with the \ option. Structures can be nested. Statics arrays are supported inside structures.

The optionnal Extends parameter allows to extends another structure with new fields. All fields found in the extended structure will be available in the new structure and will be placed before the new fields. This is useful to do basic inheritance of structures.

SizeOf can be used with structures to get the size of the structure and OffsetOf can be used to retrieve the index of the specified field.

Please note, that in structures a static array[] doesn't behave like the normal BASIC array (defined using Dim) to be conform to the C/C++ structure format (to allow direct API structure porting). This means that a[2] will allocate an array from 0 to 1 where Dim a(2) will allocate an array from 0 to 2.

Example:

  Structure Person
    Name.s
    ForName.s 
    Age.w 
  EndStructure

  Dim MyFriends.Person(100)

  ; Here the position '0' of the array MyFriend()
  ; will contain one person and it's own informations

  MyFriends(0)\Name = "Andersson"
  MyFriends(0)\Forname = "Richard" 
  MyFriends(0)\Age = 32

Example: A more complex structure (Nested and static array)

  Structure Window
    *NextWindow.Window  ; Points to another window object
    x.w 
    y.w
    Name.s[10]  ; 10 Names available (from 0 to 9)
  EndStructure

Example: Extended structure

  Structure MyPoint
    x.l 
    y.l
  EndStructure

  Structure MyColoredPoint Extends MyPoint
    color.l 
  EndStructure

  ColoredPoint.MyColoredPoint\x = 10
  ColoredPoint.MyColoredPoint\y = 20
  ColoredPoint.MyColoredPoint\color = RGB(255, 0, 0)

StructureUnion
  Field1.Type
  Field2.Type
  ...
EndStructureUnion

Structure union are only useful for advanced programmers which want to save some memory by sharing some fields inside the same structure. It's like the 'union' keyword in C/C++.

Example:

  Structure Type
    Name$
    StructureUnion
      Long.l      ; Each field (Long, Float and String) resides at the
      Float.f     ; place in memory.
      String.s    ;
    EndStructureUnion
  EndStructure