Book Image

Template Metaprogramming with C++

By : Marius Bancila
Book Image

Template Metaprogramming with C++

By: Marius Bancila

Overview of this book

Learn how the metaprogramming technique enables you to create data structures and functions that allow computation to happen at compile time. With this book, you'll realize how templates help you avoid writing duplicate code and are key to creating generic libraries, such as the standard library or Boost, that can be used in a multitude of programs. The introductory chapters of this book will give you insights into the fundamentals of templates and metaprogramming. You'll then move on to practice writing complex templates and exploring advanced concepts such as template recursion, template argument deduction, forwarding references, type traits, and conditional compilation. Along the way, you'll learn how to write variadic templates and how to provide requirements to the template arguments with C++20 constraints and concepts. Finally, you'll apply your knowledge of C++ metaprogramming templates to implement various metaprogramming patterns and techniques. By the end of this book, you'll have learned how to write effective templates and implement metaprogramming in your everyday programming journey.
Table of Contents (16 chapters)
Part 1: Core Template Concepts
Part 2: Advanced Template Features
Part 3: Applied Templates
Appendix: Closing Notes

Exploring the standard concepts library

The standard library provides a set of fundamental concepts that can be used to define requirements on the template arguments of function templates, class templates, variable templates, and alias templates, as we have seen throughout this chapter. The standard concepts in C++20 are spread across several headers and namespaces. We will present some of them in this section although not all of them. You can find all of them online at

The main set of concepts is available in the <concepts> header and the std namespace. Most of these concepts are equivalent to one or more existing type traits. For some of them, their implementation is well-defined; for some, it is unspecified. They are grouped into four categories: core language concepts, comparison concepts, object concepts, and callable concepts. This set of concepts contains the following (but not only):

Table 6.1

Some of...