C++ Templates: The Complete Guide

by David Vandevoorde, Nicolai Josuttis, Douglas Gregor

Overview

Templates are among the most powerful features of C++, but they remain misunderstood and underutilized, even as the C++ language and development community have advanced. In C++ Templates, Second Edition, three pioneering C++ experts show why, when, and how to use modern templates to build software that’s cleaner, faster, more efficient, and easier to maintain.

 

Now extensively updated for the C++11, C++14, and C++17 standards, this new edition presents state-of-the-art techniques for a wider spectrum of applications. The authors provide authoritative explanations of all new language features that either improve templates or interact with them, including variadic templates, generic lambdas, class template argument deduction, compile-time if, forwarding references, and user-defined literals. They also deeply delve into fundamental language concepts (like value categories) and fully cover all standard type traits.

 

The book starts with an insightful tutorial on basic concepts and relevant language features. The remainder of the book serves as a comprehensive reference, focusing first on language details and then on coding techniques, advanced applications, and sophisticated idioms. Throughout, examples clearly illustrate abstract concepts and demonstrate best practices for exploiting all that C++ templates can do.

• Understand exactly how templates behave, and avoid common pitfalls
• Use templates to write more efficient, flexible, and maintainable software
• Master today’s most effective idioms and techniques
• Reuse source code without compromising performance or safety
• Benefit from utilities for generic programming in the C++ Standard Library
• Preview the upcoming concepts feature

The companion website, tmplbook.com, contains sample code and additional updates.

Product Details

ISBN-13:	9780134778747
Publisher:	Pearson Education
Publication date:	09/14/2017
Sold by:	Barnes & Noble
Format:	eBook
Pages:	832
File size:	67 MB
Note:	This product may take a few minutes to download.
Age Range:	18 Years

About the Author

David Vandevoorde started programming C++ in the late 1980s. After obtaining a PhD from the Rensselaer Polytechnic Institute, he became technical lead of Hewlett-Packard’s C++ compiler team. In 1999 he joined the Edison Design Group (EDG), whose C++ compiler technology is widely recognized as the industry’s most advanced. He is an active member of the C++ Standard Committee and a moderator of the newsgroup comp.lang.c++.moderated (which he co-founded). He is the author of C++ Solutions, the companion to The C++ Programming Language, 3rd Edition.

 

Nicolai M. Josuttis is well known for his best-selling de-facto standard bookThe C++ Standard Library - A Tutorial and Reference. He is an independent technical consultant who designs object-oriented software for the telecommunications, traffic, finance, and manufacturing industries. He is an active member of the C++ Standard Committee and a partner at System Bauhaus, a German group of prominent object-oriented system development experts. Josuttis has written several other books on object-oriented programming and C++.

 

Douglas Gregor is Senior Swift/C++/Objective-C Compiler Engineer at Apple. He holds a PhD in computer science from Rensselaer Polytechnic Institute, and did post-doctoral work at Indiana University.

Read an Excerpt

The idea of templates in C++ is more than ten years old. C++ templates were already documented in 1990 in the Annotated C++ Reference Manual or so-called "ARM" (see EllisStroustrupARM) and they had been described before that in more specialized publications. However, well over a decade later we found a dearth of literature that concentrates on the fundamental concepts and advanced techniques of this fascinating, complex, and powerful C++ feature. We wanted to address this issue and decided to write the book about templates (with perhaps a slight lack of humility).

However, we approached the task with different backgrounds and with different intentions. David, an experienced compiler implementer and member of the C++ Standard Committee Core Language Working Group, was interested in an exact and detailed description of all the power (and problems) of templates. Nico, an "ordinary" application programmer and member of the C++ Standard Committee Library Working Group, was interested in understanding all the techniques of templates in a way that he could use and benefit from them. In addition, we both wanted to share this knowledge with you, the reader, and the whole community to help to avoid further misunderstanding, confusion, or apprehension.

As a consequence, you will see both conceptual introductions with day-to-day examples and detailed descriptions of the exact behavior of templates. Starting from the basic principles of templates and working up to the "art of template programming," you will discover (or rediscover) techniques such as static polymorphism, policy classes, metaprogramming, and expression templates. You will also gain a deeper understanding of the C++standard library, in which almost all code involves templates.

We learned a lot and we had much fun while writing this book. We hope you will have the same experience while reading it. Enjoy!Acknowledgments

This book presents ideas, concepts, solutions, and examples from many sources. In a way it does not seem fair that our names are the only ones on the cover. We'd like to thank all the people and companies who helped and supported us during the past few years. First, we'd like to thank all the reviewers and everyone else who gave us their opinion on early manuscripts. These people endow the book with a quality it would never have had without their input. The reviewers for this book were Kyle Blaney, Thomas Gschwind, Dennis Mancl, Patrick McKillen, and Jan Christiaan van Winkel. Special thanks to Dietmar Kuhl who meticulously reviewed and edited the whole book. His feedback was an incredible contribution to the quality of this book. We'd also like to thank all the people and companies who gave us the opportunity to test our examples on different platforms with different compilers. Many thanks to the Edison Design Groupfor their great compiler and their support. It was a big help during the standardization process and the writing of this book. Many thanks also go to all the developers of the free GNU and egcs compilers (Jason Merrill was especially responsive), and to Microsoft for an evaluation version of Visual C++ (Jonathan Caves, Herb Sutter and Jason Shirk were our contacts there).

Much of the existing "C++ Wisdom" was collectively created by the online C++ community. Most of that comes from the moderated Usenet groups comp.lang.c++.moderated and comp.std.c++. We are therefore especially indebted to the active moderators of those groups, who keep the discussions useful and constructive. We also much appreciate all those who over the years have taken the time to describe and explain their ideas for us all to share.The Addison Wesley team did another great job. We are most indebted to Debbie Lafferty (our editor) for her gentle prodding, good advice, and relentless hard work in support of this book. We're grateful also to Marina Lang who first sponsored this book within Addison Wesley. Susan Winer contributed an early round of editing that helped shape our later work.Nico's Acknowledgments

My first personal thanks goes with a lot kisses to my family: Ulli, Lucas, Anica, and Frederic did support this book with a lot patience, consideration, and spur. In addition, I want to thank David. His expertise turned out to be incredible. But, his patience was even better (sometimes I ask really silly questions). It is a lot of fun to work with him.David's Acknowledgments

My wife Karina has been instrumental in this book coming to a conclusion and I am immensely grateful for the role that she plays in my life. Writing "in your spare time" quickly becomes erratic when many other activities vie for your schedule. Karina helped me to manage that schedule, taught me to say "No" in order to make the time needed to make regular progress in the writing process,and above all was amazingly supportive of this project. I thank God every day for her friendship and love.

I'm also tremendously grateful to have been able to work with Nico. Besides his directly visible contributions to the text, his experience and discipline moved us from my pitiful doodling to a well organized production.John "Mr. Template" Spicer and Steve "Mr. Overload" Adamczyk are wonderful friends and colleagues, but in my opinion they are (together) also the ultimate authority regarding the core C++ language. They clarified many of the trickier issues described in this book, and should you find an error in the description of a C++ language element, it is almost certainly attributable to my failing toconsult with them.

Finally, I want to express my appreciation to those who were supportive of this project without necessarily contributing to it directly (the power of cheer cannot be understated). First are my parents: Their love for me and their encouragements make all the difference. And then, there are the numerous friends constantly asking "How is the book going?"; they too were a source of encouragement: Michael Beckmann, Brett and Julie Beene, Jarran Carr, Simon Chang, Ho and Sarah Cho, Christophe De Dinechin, Peter and Ewa Deelman, Neil and Tammy Eberle, Sassan Hazeghi, Vikram Kumar, Jim and Lindsay Long, Franklin Luk, Richard and Marianna Morgan, Ragu Raghavendra, Jim and Phuong Sharp, Gregg Vaughn, and John Wiegley.

Table of Contents

• Part I: The Basics
• Chapter 1: Function Templates
• Chapter 2: Class Templates
• Chapter 3: Nontype Template Parameters
• Chapter 4: Variadic Templates
• Chapter 5: Tricky Basics
• Chapter 6: Move Semantics and enable_if<>
• Chapter 7: By-Value or By-Reference?
• Chapter 8: Compile-Time Programming
• Chapter 9: Using Templates in Practice
• Chapter 10: Basic Template Terminology
• Chapter 11: Generic Libraries
• Part II: Templates in Depth
• Chapter 12: Fundamentals in Depth
• Chapter 13: Names in Templates
• Chapter 14: Instantiation
• Chapter 15: Template Argument Deduction
• Chapter 16: Specialization and Overloading
• Chapter 17: Future Directions
• Part III: Templates and Design
• Chapter 18: The Polymorphic Power of Templates
• Chapter 19: Implementing Traits
• Chapter 20: Overloading on Type Properties
• Chapter 21: Templates and Inheritance
• Chapter 22: Bridging and Static and Dynamic Polymorphism
• Chapter 23: Metaprograms
• Chapter 24: Typelists
• Chapter 25: Tuples
• Chapter 26: Discriminated Unions
• Chapter 27: Expression Templates
• Chapter 28: Debugging Templates
• Appendixes
• Appendix A: The One-Definition Rule
• Appendix B: Value Categories
• Appendix C: Overload Resolution
• Appendix D: Standard Type and Meta Utilities
• Appendix E: Concepts
• Bibliography
• Glossary
• Index    

Preface

The idea of templates in C++ is more than ten years old. C++ templates were already documented in 1990 in the Annotated C++ Reference Manual or so-called "ARM" (see EllisStroustrupARM) and they had been described before that in more specialized publications. However, well over a decade later we found a dearth of literature that concentrates on the fundamental concepts and advanced techniques of this fascinating, complex, and powerful C++ feature. We wanted to address this issue and decided to write the book about templates (with perhaps a slight lack of humility).

However, we approached the task with different backgrounds and with different intentions. David, an experienced compiler implementer and member of the C++ Standard Committee Core Language Working Group, was interested in an exact and detailed description of all the power (and problems) of templates. Nico, an "ordinary" application programmer and member of the C++ Standard Committee Library Working Group, was interested in understanding all the techniques of templates in a way that he could use and benefit from them. In addition, we both wanted to share this knowledge with you, the reader, and the whole community to help to avoid further misunderstanding, confusion, or apprehension.

As a consequence, you will see both conceptual introductions with day-to-day examples and detailed descriptions of the exact behavior of templates. Starting from the basic principles of templates and working up to the "art of template programming," you will discover (or rediscover) techniques such as static polymorphism, policy classes, metaprogramming, and expression templates. You will also gain a deeper understanding of the C++standard library, in which almost all code involves templates.

We learned a lot and we had much fun while writing this book. We hope you will have the same experience while reading it. Enjoy!

Acknowledgments

This book presents ideas, concepts, solutions, and examples from many sources. In a way it does not seem fair that our names are the only ones on the cover. We'd like to thank all the people and companies who helped and supported us during the past few years. First, we'd like to thank all the reviewers and everyone else who gave us their opinion on early manuscripts. These people endow the book with a quality it would never have had without their input. The reviewers for this book were Kyle Blaney, Thomas Gschwind, Dennis Mancl, Patrick McKillen, and Jan Christiaan van Winkel. Special thanks to Dietmar Kuhl who meticulously reviewed and edited the whole book. His feedback was an incredible contribution to the quality of this book. We'd also like to thank all the people and companies who gave us the opportunity to test our examples on different platforms with different compilers. Many thanks to the Edison Design Groupfor their great compiler and their support. It was a big help during the standardization process and the writing of this book. Many thanks also go to all the developers of the free GNU and egcs compilers (Jason Merrill was especially responsive), and to Microsoft for an evaluation version of Visual C++ (Jonathan Caves, Herb Sutter and Jason Shirk were our contacts there).

Much of the existing "C++ Wisdom" was collectively created by the online C++ community. Most of that comes from the moderated Usenet groups comp.lang.c++.moderated and comp.std.c++. We are therefore especially indebted to the active moderators of those groups, who keep the discussions useful and constructive. We also much appreciate all those who over the years have taken the time to describe and explain their ideas for us all to share.The Addison Wesley team did another great job. We are most indebted to Debbie Lafferty (our editor) for her gentle prodding, good advice, and relentless hard work in support of this book. We're grateful also to Marina Lang who first sponsored this book within Addison Wesley. Susan Winer contributed an early round of editing that helped shape our later work.

Nico's Acknowledgments

My first personal thanks goes with a lot kisses to my family: Ulli, Lucas, Anica, and Frederic did support this book with a lot patience, consideration, and spur. In addition, I want to thank David. His expertise turned out to be incredible. But, his patience was even better (sometimes I ask really silly questions). It is a lot of fun to work with him.

David's Acknowledgments

My wife Karina has been instrumental in this book coming to a conclusion and I am immensely grateful for the role that she plays in my life. Writing "in your spare time" quickly becomes erratic when many other activities vie for your schedule. Karina helped me to manage that schedule, taught me to say "No" in order to make the time needed to make regular progress in the writing process,and above all was amazingly supportive of this project. I thank God every day for her friendship and love.

I'm also tremendously grateful to have been able to work with Nico. Besides his directly visible contributions to the text, his experience and discipline moved us from my pitiful doodling to a well organized production.John "Mr. Template" Spicer and Steve "Mr. Overload" Adamczyk are wonderful friends and colleagues, but in my opinion they are (together) also the ultimate authority regarding the core C++ language. They clarified many of the trickier issues described in this book, and should you find an error in the description of a C++ language element, it is almost certainly attributable to my failing toconsult with them.

Finally, I want to express my appreciation to those who were supportive of this project without necessarily contributing to it directly (the power of cheer cannot be understated). First are my parents: Their love for me and their encouragements make all the difference. And then, there are the numerous friends constantly asking "How is the book going?"; they too were a source of encouragement: Michael Beckmann, Brett and Julie Beene, Jarran Carr, Simon Chang, Ho and Sarah Cho, Christophe De Dinechin, Peter and Ewa Deelman, Neil and Tammy Eberle, Sassan Hazeghi, Vikram Kumar, Jim and Lindsay Long, Franklin Luk, Richard and Marianna Morgan, Ragu Raghavendra, Jim and Phuong Sharp, Gregg Vaughn, and John Wiegley.

Editorial Reviews

The Barnes & Noble Review
It’s now over a decade since C++ templates were first conceived, yet many C++ programmers still don’t understand them thoroughly and don’t understand just how powerful they can be. Moreover, some developers who try to use templates often find themselves surprised by behavior they would’ve expected if they really understood how C++ supports template-based techniques. In C++ Templates, David Vandevoorde and Nicolai M. Josuttis set out to remedy this -- and they succeed.

The authors begin by introducing function and class templates, nontype template parameters, and several of what they (accurately) call “tricky basics.” They walk through using templates in practice, then move on to in-depth discussions of template naming, instantiation, specialization, overloading, and design issues. The book concludes with an entire section on advanced applications utilizing type classification, smart pointers, tuples, and other techniques.

Vandevoorde, one of the world’s leading C++ compiler experts, co-founded and moderates the comp.lang.c++.moderated newsgroup. Josuttis wrote one of the world’s most widely used C++ books, The C++ Standard Library: A Tutorial and Reference. They’re both on the C++ standards committees. Few people can touch their knowledge of C++ and templates. You’ll really appreciate having that knowledge at your fingertips. Bill Camarda

Bill Camarda is a consultant, writer, and web/multimedia content developer. His 15 books include Special Edition Using Word 2000 and Upgrading & Fixing Networks For Dummies®, Second Edition.