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


In this chapter, we have explored an important category of templates, variadic templates, which are templates with a variable number of template arguments. We can create variadic function templates, class templates, variable templates, and alias templates. The techniques to create variadic function templates and variadic class templates are different but incur a form of compile-time recursion. For the latter, this is done with template specialization, while for the former with function overloads. Fold expressions help to expand a variable number of arguments into a single expression, avoiding the need of using function overloads and enabling the creation of some categories of variadic variable templates such as the ones we have previously seen.

In the next chapter, we will look into a series of more advanced features that will help you consolidate your knowledge of templates.