Preface

C++ of today provides programmers the ability to write expressive and robust code while still having the ability to target almost any hardware platform or real-time requirements. This makes C++ a unique language. Over the last few years, C++ has turned into a modern language that is more fun to use and with better defaults.

This book aims to give the reader a solid foundation to write efficient applications as well as an insight into strategies for implementing libraries in modern C++. We have tried to take a practical approach to explain how C++ works today, where C++14/C++17 features are a natural part of the language, rather than looking at C++ historically.

This book has been written by us, Viktor and Björn, collaboratively. However, the drafts of each chapter were written individually, and after that, we have worked together to improve the chapters and assemble them into a complete book. Viktor is the main author of chapter 1, 2, 5, 8, 9, and 11. Björn is the main author of chapter 3, 4, 7, and 10. We have worked hard to attain a consistent style throughout the book, and we think that it has been a big advantage to write this book together. Many subjects have been debated and processed for the better.

Who this book is for

This book expects you to have a basic knowledge of C++ and computer architecture and a genuine interest in evolving your skills. Hopefully, by the time you finish this book, you will have gained a few insights into how you can improve your C++ applications, both performance-wise and syntactically. On top of that, we also hope that you will have a few aha moments.

What this book covers

Chapter 1, A Brief Introduction to C++, introduces some important properties of C++ such as zero-cost abstractions, value semantics, const correctness, explicit ownership, and error handling. It also discusses the drawbacks of C++.

Chapter 2, Modern C++ Concepts, outlines automatic type deduction using auto, lambda functions, move semantics, std::optional, and std::any.

Chapter 3, Measuring Performance, discusses asymptotic complexity and big O notation, practical performance testing, and how to profile your code to find hotspots.

Chapter 4, Data Structures, takes you through the importance of structuring the data so that it can be accessed quickly. STL containers such as std::vector, std::list, std::unordered_map, and std::priority_queue are introduced. Finally, we describe how to iterate over parallel arrays.

Chapter 5, A Deeper Look at Iterators, dives into the concept of iterators, and shows how iterators can go beyond just referring to objects in containers.

Chapter 6, STL Algorithms and Beyond, shows the obvious, and the not so obvious, advantages of STL algorithms over hand rolled for loops. It also takes a look at the limitations of STL algorithms and how the new Ranges library overcomes these limits.

Chapter 7, Memory Management, focuses on safe and efficient memory management. This includes memory ownership, RAII, smart pointers, stack memory, dynamic memory, and custom memory allocators.

Chapter 8, Metaprogramming and Compile-Time Evaluation, explains metaprogramming concepts such as constexpr, heterogeneous containers, type_traits, std::enable_if, and std::is_detected. It also gives practical examples of metaprogramming use cases, such as reflection.

Chapter 9, Proxy Objects and Lazy Evaluation, explores how proxy objects can be used to perform under-the-hood optimizations while preserving clean syntax. Additionally, some creative uses of operator-overloading are demonstrated.

Chapter 10, Concurrency, covers the fundamentals of concurrent programming, including parallel execution, shared memory, data races, and deadlocks. It also includes an introduction to the C++ thread support library, the atomic library, and the C++ memory model.

Chapter 11, Parallel STL, starts by showing the complexity of writing parallel algorithms. It then demonstrates how to utilize STL algorithms in a parallel context using the parallel extensions for STL and Boost Compute.

To get the most out of this book

To get the most out of this book, you need to have a basic knowledge of C++. It's preferable if you have already been facing problems related to performance and are now looking for new tools and practices to have ready the next time you need to work with performance and C++.

There are a lot of code examples in this book. Some are taken from the real world, but most of them are artificial or vastly simplified examples to prove a concept rather than providing you with production-ready code. We have put all the code examples in source files divided by chapter so that it is fairly easy to find the examples you want to experiment with. If you open up the source code files, you will note that we have replaced most of the main() functions from the examples with test cases written with Google Test framework. We hope that this will help you rather than confuse you. It allowed us to write helpful descriptions for each example, and it also makes it easier to run all the examples from one chapter at once.

In order to compile and run the examples, you will need the following:

• A computer
• An operation system (we have verified the examples on Windows and macOS)
• A compiler (we have been using Clang, GCC, and Microsoft Visual C++)
• CMake

The CMake script provided with the example code will download and install further dependencies such as Boost, OpenCL, and Google Test.

During the writing of this book, it has been of great help for us to use Compiler Explorer, which is available at https://godbolt.org/. Compiler Explorer is an online compiler service that lets you try various compilers and versions. Try it out if you haven't already!

Download the example code files

You can download the example code files for this book from your account at www.packtpub.com. If you purchased this book elsewhere, you can visit www.packtpub.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packtpub.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Cpp-High-Performance. We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, folder names, filenames, file extensions, dummy URLs, and user input. Here is an example: "The keyword constexpr was introduced in C++11."

A block of code is set as follows:

#include <iostream>

auto main() -> int {
  std::cout << "High Performance C++\n";
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

#include <iostream>

auto main() -> int {
  std::cout << "High Performance C++\n";
}

Any command-line input or output is written as follows:

$ clang++ -std=c++17 high_performance.cpp
$ ./a.out
$ High Performance C++

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Select System info from the Administration panel."

Warnings or important notes appear like this.

Tips and tricks appear like this.

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