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Gem #36: Safe and Secure Software : Chapter 3, Safe Pointers
Author: John Barnes
Abstract: This week’s gem is the third chapter of John Barnes’ new booklet:
Safe and Secure Software: An Introduction to Ada 2005.
Over the coming months, we will be publishing all thirteen chapters of the booklet. In the attachment at the bottom of Gem #30 you can access the contents and bibliography for the entire booklet. We hope you will enjoy the read!
Let’s get started…
Primitive man made a huge leap forward with the discovery of fire. Not only did this allow him to keep warm and cook and thereby expand into more challenging environments but it also enabled the creation of metal tools and thus the bootstrap to an industrial society. But fire is dangerous when misused and can cause tremendous havoc; observe that society has special standing organizations just to deal with fires that are out of control.
Software similarly made a big leap forward in its capabilities when the notion of pointers or references was introduced. But playing with pointers is like playing with fire. Pointers can bring enormous benefits but if misused can bring immediate disaster such as a blue screen, or allow a rampaging program to destroy data, or create the loophole through which a virus can invade.
High integrity software typically limits drastically the use of pointers. The access types of Ada have the semantics of pointers but in addition carry numerous safeguards on their use, which makes them safe in the most demanding safety-critical programs.
Read Chapter 3 in full
Note: All chapters of this booklet will, in time, be available on the Ada 2005 home page.
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in Ada / Ada 2005, Development Log, Devt log - Gem of the Week
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