This guide is an ongoing work. If you have
any queries or suggestions concerning style, subject matter, or presentation
of this guide, then do not hesitate to email the author at email@example.com.
The latest on line copy of this document can be found on Martin Harvey's
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of HTML pages, or as a zip
Thanks to the hard work of Michael Cessna, a copy is also available
in HTML help format.
In the event of slow downloads from this site, a zipped copy is also
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This document last updated on Sunday April 1st 2001.
Multithreading - The Delphi Way.
Table of Contents.
Chapter 1. What are threads? Why use them?
Chapter 2. Creating a thread in Delphi.
Chapter 3. Basic synchronization.
Chapter 4. Simple thread destruction.
Chapter 5. More thread destruction. Deadlock.
Chapter 6. More synchronization: Critical sections
Chapter 7. Mutex programming guidelines. Concurrency
Chapter 8. Delphi thread safe classes and Priorities.
Chapter 9. Semaphores. Data flow scheduling.
The producer - consumer relationship.
Chapter 10. I/O and data flow: from blocking
to asynchronous and back.
Chapter 11. Synchronizers and Events.
Chapter 12. More Win32 synchronization facilities.
Chapter 13. Using threads in conjunction with
the BDE, Exceptions and DLLs.
Chapter 14. A real world problem, and its solution.
This guide is intended for anyone who is interested in improving performance
and responsiveness in their Delphi applications by using threads. It covers
a range of topics from absolute beginner to intermediate level, and some
of the real world examples raise issues bordering on the advanced. It assumes
that the reader has a reasonable knowledge of Object Pascal programming,
including simple object orientation, and a working understanding of event
Dedicated to three members of the Computer Science department at the University
of Cambridge: Dr Jean Bacon, Dr Simon Crosby, and Dr Arthur Norman.
Many thanks to Jean as a tutor for making a complicated subject seem
simple, for providing excellent reference material, and for lifting a corner
of the veil around a hitherto mysterious subject. She also deserves thanks
as a director of studies, for explaining the Computer science timetable
to me. It took me three years to figure it out for myself!
Many thanks to Simon as a tutor, for showing me that although modern
operating systems may be fiendishly complicated, the principles underlying
them are simple. He also deserves thanks for taking on a student with unconventional
ideas about final year project material, and for providing much useful
advice on my project dissertation.
Arthur Norman never taught me a thing about multithreading. He did however
teach me many other things, which helped me when writing the more complicated
parts of this guide:
He also deserves a mention for some of the best quotes ever to fall from
a computer science lecturers lips:
There is no limit to the eccentricity of university lecturers.
Although most people prefer simplicity, there is a certain perverse enjoyment
to be had doing things the complicated way, especially if you're cynical.
He even has his own fan page.
"There is something in the lecture course which may not have been visible
so far, which is reality ..."
"The theoreticians have proven that this is unsolvable, but there's three
of us, and we're smart ..."
"People who don't use computers are more sociable, reasonable, and ...
"[If complexity theory lives up to its title] if that proves to be the
case, I will be the winner, as not many of you will attempt the exam questions."
Title: Concurrent Systems: An integrated approach to Operating Systems,
Database, and Distributed Systems.
Author: Jean Bacon.
The author welcomes suggestions for other useful titles.
The narrative and diagrams in this guide are all contained in single HTML
pages, one for each chapter. The source code examples appear in pop up
viewing of the narrative and source in parallel, the reader may find it
useful to tile the various web browser windows. This can be achieved by
right clicking on the task bar, and selecting "Tile Windows Vertically".
Corrected some spelling and punctuation errors in the prose, and rewrote
some unclear explanations. Chapters 1-9 and 12 modified.
Added change history and other credits to contents page.
Renamed Chapter 12.
Added Chapter 14.
Many thanks to the following people for reviewing, suggesting, correcting
and generally improving this guide:
Dr John Stockton
© Martin Harvey