Table Of ContentC++
GEMS
SIGS REFERENCE LIBRARY
Donald G. Firesmith
Editor-in-Chief
1. Object Methodology Overview, CD-ROM, Doug Rosenberg
2. Directory of Object Technology, edited by Dale f. Gaumer
3. Dictionary of Object Technology: The Definitive Desk
Reference, Donald G. Firesmith and Edward M. Eykholt
4. Next Generation Computing: Distributed Objects for
Business, edited by Peter Fingar, Dennis Read,
and Jim Stikeleather
S. C++ Gems, edited by Stanley B. Lippman
6. OMT Insights: Perspectives on Modeling from the journal
of Object-Oriented Programming, fames Rumbaugh
1. Best of Booch: Designing Strategies for Object Technology,
Grady Booch (Edited by Ed Eykholt)
8. Wisdom of the Gurus: A Vision for Object Technology,
selected and edited by Charles F. Bowman
9. Open Modeling Language (OML) Reference Manual,
Donald G. Firesmith, Brian Henderson-Sellers, and Ian Graham
10. javam Gems: jewels from Java.,.., Report,
collected and introduced by Dwight Deugo, Ph.D.
11. The Netscape Programmer's Guide: Using OLE to Build
Componentwaren~ Apps, Richard B. Lam
12. Advanced Object-Oriented Analysis and Design Using UML,
fames f. Odell
13. The Patterns Handbook: Techniques, Strategies, and
Applications, selected and edited by Linda Rising
Additional Volumes in Preparation
C++
GEMS
EDITED BY
STANLEY B. LIPPMAN
S I G S
CAMBRIDGE
UNIVERSITY PRESS BOOKS
PUBLISHED BY THE PRESS SYNDICATE OF THE UNIVERSITY OF CAMBRIDGE
The Pitt Building, Trumpington Street, Cambridge, United Kingdom
CAMBRIDGE UNIVERSITY PRESS
The Edinburgh Building, Cambridge CB2 2RU, UK www.cup.cam.ac.uk
40 West 20th Street, New York, NY 10011-4211, USA www.cup.org
10 Stamford Road, Oakleigh, Melbourne 3166, Australia
Ruiz de Alarcon 13, 28014 Madrid, Spain
Published in association with SIG Books and Multimedia
© Cambridge University Press 1998
All rights reserved
This book is in copyright. Subject to statutory exception
and to the provisions of relevant collective licensing agreements,
no reproduction of any part may take place without
the written permission of Cambridge University Press.
Any product mentioned in this book, may be a trademark of its company
First published by SIGS Books and Multimedia1996
First published by Cambridge University Press 1998
Reprinted 1999
Printed in the United States of America
Design and companion by Kevin Callahan
Cover design by Yin Moy
Typeset in Adobe Garamond
A catalog record for this book is available .from the British Library
Library of Congress Cataloging in Publication Data is available
ISBN 0 13 570581 9 paperback
ABOUT THE EDITOR
STANLEY B. LIPPMAN CURRENTLY IS A PRINCIPAL SOFTWARE ENGINEER
in the development technology group of Walt Disney Feature Animation.
Prior to that, he spent over 10 years at Bell Laboratories. He began working
with C++ back in 1985 and led the Laboratory's C++ cfront Release 3.0 and
Release 2.1 compiler development teams. He was also a member of the Bell
Laboratories Foundation Project under Bjarne Stroustrup and was responsible
for the Object Model component of a research C++ programming environment.
Lippman is the author of two highly successful editions of C++ Primer and of
the recendy released Inside the C++ Object Model both published by Addison
Wesley. He has spoken on and taught C++ worldwide.
Lippman recendy "retired" as editor of C++ Report, which he edited for
nearly four years.
v
FOREWORD
FOREWORDS FOR TECHNICAL BOOKS ARE TYPICALLY WRITTEN TO IMPRESS
the potential reader with the technical expertise and skills of the author(s).
In this case, the task is pointless: The authors whose work appears here repre
sent a cross-section of the most widely known and respected C++ experts. Their
technical skills are beyond question. But technical skills are only part of the
equation. The C++ Report has been successful in getting topnotch technical
people to write articles that are not only technically impressive but actually
interesting and useful. There are several reasons for this:
• The authors really use this stuff. When we started the C++ Report in late
1989, we decided to target the people who wrote C++ code for a living.
High-level management overviews were left to the competition. After all,
we reasoned, there are more C++ programmers in the world than there are
C++ managers. To write articles for programmers, we needed to find
authors who were programmers.
• The editors really use this stuff. All the editors have been C++ program- •
mers first and editors second. We have tended to choose articles that we
personally found interesting. We were also able to spot (and reject) sub
missions that were polished but technically flawed.
• The articles are short. Ostensibly, this was to ensure that readers would get
a condensed digest of the most critical material without having to invest a
great deal of time. Short articles had other advantages for us. We had a
competitor (now long since defunct) that was trying to be a forum for
long articles. We were happy to concede this niche, because we thought
that 20-page articles were the province of academic journals (who wants to
Vtt
FOREWORD
compete with CACM?). There was also the matter of perceived effort.
Nobody was going to get rich at the rates we paid, so we were essentially
asking people to write for the good of their careers and for the language in
general. We figured we could get more authors if we asked them to write
short articles.
• Technical content was more important than artistic beauty. As Stan
Lippman comments in his introduction to this book, the first issue of the
C++ Report had a far from polished appearance. This was deliberate; we
even decided not to print it on glossy paper despite the fact that the cost
was the same. We wanted to look like a newsletter, not a magazine.
Obviously, today's C++ Report pays much more attention to appearances
than we did in 1990, but unlike certain men's magazines, people really do
look at the Report for the articles, not for the pictures.
Now that I've left AT&T Bell Labs and become a management type at
Quantitative Data Systems, I've noticed one more interesting thing. The C++
Report has become a useful management tool, in large part because it does not
try to cater to managers. Though I no longer read every line of code in the
examples, I still learn a lot about C++ from reading the Report. Good ideas and
good practices in this business tend to percolate from the bottom up. I trust the
opinions and judgments of people who are doing actual work.
Stan has assembled a truly remarkable collection, valuable not just for its his
torical interest but also for its technical merit. The time spent reading these arti
cles will be a valuable investment for anyone who uses C++.
Robert Murray
Irvine, California
January 1996
viii
INTRODUCTION:
THE C++ REPORT-SO FAR
STAN LIPPMAN
T HE C++ REPORT PUBLISHED ITS FIRST ISSUE IN JANUARY 1989. ROB
Murray, the founding editor, had agreed to take on the task back in October
1988. At the time, cfront release 2.0 was still in beta and would not be released
for another nine months (we still had to add canst and static member func
tions, abstract base classes, and support for pure virtual functions, apart from any
debugging that remained). Bjarne [Stroustrup] estimates at the time there were
approximately 15,000 C++ users1-enough perhaps to fill the Royal Albert Hall,
but support a magazine devoted to covering C++? Nobody was sure. As Rick
Friedman, the founder and publisher of SIGS Publications, writes2:
Just between you and me, I must confess I was worried. There I was, trav
eling back on the train from Liberty Corner, New Jersey, having just con
vinced AT&T Bell Labs' Rob Murray that he should edit a start-up
publication on C++. "We only need 1,000 subscribers to make it all go," I
told him confidently. Returning to my office, I looked dazedly out the
window at the passing countryside, my head buzzing with strategies on
how and where to find the critical mass of readers.
You see, this was back in October 1988 ... and it was unclear which,
if any, OOP language would emerge as winner. Several software pun
dits, including Bertrand Meyer, OOP's notorious enfant terrible, vocif
erously predicted doom for C++. But all the very early signs indicated
to me that C++ would eventually gain popularity. It would then need
an open forum, I postulated. So I rolled the dice.
Or, as Barbara Moo, my supervisor at Bell Laboratories for many years used to say,
"Everybody into the pool., Let's try to remember the C++ landscape back then.
INTRODUCTION
October 1988: Borland would not provide its C++ compiler until May,
1990. Microsoft, after a false start, lurched across the compiler line, led by
Martin O'Riordan, in March 1992. (Martin and Jon Carolan were the first to
pon cfront to the PC back in 1986 under Carolan's Glockinspiel company.
Greg Comeau also provided an early cfront port to the PC.) Who else was out
there back then? Michael Tiemann provided his g++ GNU compiler, version
1.13, in December 1987. Michael Ball and Steve Clamage delivered TauMetric's
commercial compiler to Oregon Software in January 1988. Walter Bright's PC
compiler was brought to the market in June 1988 through Zortech (now owned
by Symantec). The full set of available books on C++ was less than a fistful. My
book, for example, C++ Primer, was still under development, as was the
Dewhurst and Stark book; Coplien hadn't even begun his yet.
The first issue of the C++ Report in fact proved to be a (relatively) smashing
success: a first printing of 2,000 copies sold out; a second printing of 2,000 also
sold out. Were you to look at the first issue now, honestly, I think you'd feel
more than a tad disappointed. There's nothing glossy or hi-tech about it: it
reminds me of the early c&ont releases. No fancy color, but a lot of content.
The first issue is 16 pages, except the back page isn't a page at all: it has a sub
scription form and a blank bottom half that looks like a hotel postcard you get
free if you poke around the middle drawer of the hotel room desk. Bjarne
begins the first issue of the first page with an article on the soon-to-begin C++
standards work. There are five advertisements: three for C++ compilers (Oregon
Software, Oasys, and Apollo Computers-back then, anyway, AT&T not only
didn't take out any ads for cfront but didn't have a full-time marketing represen
tative), and two for training (Semaphore and something called the Institute for
Zero Defect Software, which, not surprisingly with a mandate like that, no
longer seems to be in operation). No libraries, no programming support envi
ronments, no GUI builders: C++ was still in Lewis and Clark territory.
The Report published 10 issues per year for its first three years, at 16 pages in
1989, 24 pages in 1990, and 32 pages in 1991. 1991 was an important water
shed for C++: we (that is, Bell Laboratories) had finally nudged cfront release
2.0-then the de facto language standard, and the first to provide multiple
inheritance, class instance operators new and delete, const and static mem
ber functions, etc.-out the door. More important, perhaps, the Annotated C++
Reference Manual (a.k.a. the ARM) by Bjarne and Peggy Ellis had been pub
lished,* as well as Bjarne's second edition of his classic The C++ Programming
* This is important for three reasons: (I) the obvious reason, of course, is that it provided a
(reasonably) concise and complete (well, perhaps templates were a necessary exception!) defin
icion of the language, (2) it provided detailed commentary on implementation strategy, and
(3) the most significant reason is that it had undergone an industry-wide review incorporating
x criticisms/comments from companies such as Microsoft, Apple, IBM, Thinking Machines, etc.
