Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
Nodes       : 1117
Index Size  : 32614
HCP-Version : 6
Compiled on : Atari
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           The ob_next, ob_head, and ob_tail fields of an OBJECT


The ob_next, ob_head, and ob_tail fields determine this relationship
between parent OBJECTs and child OBJECTs. The following alert box is an
example of an OBJECT tree:



The tree structure this object has can be represented as follows:

                             [ROOT OBJECT]
                            Object #0 - BOX
                              ob_head = 1
                              ob_tail = 5
                              ob_next =-1


     Object #1 - TEXT       Object #2 - BOX       Object #5 - BUTTON
       ob_head = -1           ob_head = 3            ob_head = -1
       ob_tail = -1           ob_tail = 4            ob_tail = -1
       ob_next =  2           ob_next = 5            ob_next =  0


             Object #3 - BOXTEXT      Object #4 - BOXTEXT
                 ob_head = -1             ob_head = -1
                 ob_tail = -1             ob_tail = -1
                 ob_next =  4             ob_next =  2


The exact usage of ob_head, ob_next, and ob_tail are as follows:

Element  Usage

ob_head  This member gives the exact index from the first object in the
         OBJECT tree to the first child of the current object. If the
         object has no children then this value should be -1.

ob_tail  This member gives the exact index from the first object in the
         OBJECT tree to the last child of the current object. If the
         object has no children then this value should be -1.

ob_next  This member gives the exact index from the first object in the
         OBJECT tree to the next child at the same level. The ROOT object
         should be set to -1. The last child at any given nesting level
         should be set to the index of its parent.