Williams - C++ Concurrency in Action,2E

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To Kim, Hugh, and Erin

Its not just the best current treatment of C++11s threading facilities ... its likely to remain the best for some time to come.

Scott Meyers, author of Effective C++ and More Effective C++

Simplifies the dark art of C++ multithreading.

Rick Wagner, Red Hat

Reading this made my brain hurt. But its a good hurt.

Joshua Heyer, Ingersoll Rand

Anthony shows how to put concurrency into practice.

Roger Orr, OR/2 Limited

A thoughtful, in-depth guide to the new concurrency standard for C++ straight from the mouth of one the horses.

Neil Horlock, Director, Credit Suisse

Any serious C++ developers should understand the contents of this important book.

Dr. Jamie Allsop, Development Director

I encountered the concept of multithreaded code while working at my first job after I left college. We were writing a data processing application that had to populate a database with incoming data records. There was a lot of data, but each record was independent and required a reasonable amount of processing before it could be inserted into the database. To take full advantage of the power of our 10-CPU UltraSPARC, we ran the code in multiple threads, each thread processing its own set of incoming records. We wrote the code in C++, using POSIX threads, and made a fair number of mistakesmultithreading was new to all of usbut we got there in the end. It was also while working on this project that I first became aware of the C++ Standards Committee and the freshly published C++ Standard.

I have had a keen interest in multithreading and concurrency ever since. Where others saw it as difficult, complex, and a source of problems, I saw it as a powerful tool that could enable your code to take advantage of the available hardware to run faster. Later on, I would learn how it could be used to improve the responsiveness and performance of applications even on single-core hardware, by using multiple threads to hide the latency of time-consuming operations such as I/O. I also learned how it worked at the OS level and how Intel CPUs handled task switching.

Meanwhile, my interest in C++ brought me in contact with the ACCU and then the C++ Standards panel at BSI, as well as Boost. I followed the initial development of the Boost Thread Library with interest, and when it was abandoned by the original developer, I jumped at the chance to get involved. I was the primary developer and maintainer of the Boost Thread Library for a number of years, though I have since handed that responsibility on.

As the work of the C++ Standards Committee shifted from fixing defects in the existing standard to writing proposals for the C++11 standard (named C++0x in the hope that it would be finished by 2009, and then officially C++11, because it was finally published in 2011), I got more involved with BSI and started drafting proposals of my own. Once it became clear that multithreading was on the agenda, I jumped in with both feet and authored or co-authored many of the multithreading and concurrency-related proposals that shaped this part of the standard. I have continued to be involved with the concurrency group as we worked on the changes for C++17, the Concurrency TS, and proposals for the future. I feel privileged to have had the opportunity to combine two of my major computer-related interestsC++ and multithreadingin this way.

This book draws on all my experience with both C++ and multithreading and aims to teach other C++ developers how to use the C++17 Thread Library and Concurrency TS safely and efficiently. I also hope to impart some of my enthusiasm for the subject along the way.

I will start by saying a big Thank you to my wife, Kim, for all the love and support she has given me while writing this book. The first edition occupied a significant part of my spare time for the four years before publication, and the second edition has again required a significant investment of time, and without her patience, support, and understanding, I couldnt have managed it.

Second, I would like to thank the team at Manning who have made this book possible: Marjan Bace, publisher; Michael Stephens, associate publisher; Cynthia Kane, my development editor; Aleksandar Dragosavljevi, review editor; Safis Editing and Heidi Ward, my copyeditors; and Melody Dolab, my proofreader. Without their efforts you would not be reading this book right now.

I would also like to thank the other members of the C++ Standards Committee who wrote committee papers on the multithreading facilities: Andrei Alexandrescu, Pete Becker, Bob Blainer, Hans Boehm, Beman Dawes, Lawrence Crowl, Peter Dimov, Jeff Garland, Kevlin Henney, Howard Hinnant, Ben Hutchings, Jan Kristofferson, Doug Lea, Paul McKenney, Nick McLaren, Clark Nelson, Bill Pugh, Raul Silvera, Herb Sutter, Detlef Vollmann, and Michael Wong, plus all those who commented on the papers, discussed them at the committee meetings, and otherwise helped shaped the multithreading and concurrency support in C++11, C++14, C++17, and the Concurrency TS.

Finally, I would like to thank the following people, whose suggestions have greatly improved this book: Dr. Jamie Allsop, Peter Dimov, Howard Hinnant, Rick Molloy, Jonathan Wakely, and Dr. Russel Winder, with special thanks to Russel for his detailed reviews and to Frdric Flayol, who, as technical proofreader, painstakingly checked all the content for outright errors in the final manuscript during production. (Any remaining mistakes are, of course, all mine.) In addition, Id like to thank my panel of reviewers for the second edition: Al Norman, Andrei de Arajo Formiga, Chad Brewbaker, Dwight Wilkins, Hugo Filipe Lopes, Vieira Durana, Jura Shikin, Kent R. Spillner, Maria Gemini, Mateusz Malenta, Maurizio Tomasi, Nat Luengnaruemitchai, Robert C. Green II, Robert Trausmuth, Sanchir Kartiev, and Steven Parr. Also, thanks to the readers of the MEAP edition who took the time to point out errors or highlight areas that needed clarifying.