Book Image

Template Metaprogramming with C++

By : Marius Bancila
5 (1)
Book Image

Template Metaprogramming with C++

5 (1)
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)
1
Part 1: Core Template Concepts
5
Part 2: Advanced Template Features
9
Part 3: Applied Templates
Appendix: Closing Notes

Chapter 5, Type Traits and Conditional Compilation

Question 1

What are type traits?

Answer

Type traits are small class templates that enable us to either query properties of types or perform transformations of types.

Question 2

What is SFINAE?

Answer

SFINAE is an acronym for Substitution Failure Is Not An Error. This is a rule for template substitution and works as follows: when the compiler encounters the use of a function template, it substitutes the arguments in order to instantiate the template; if an error occurs at this point, it is not regarded as an ill-formed code, only as a deduction failure. As a result, the function is removed from the overload set instead of causing an error. Therefore, an error only occurs if there is no match in the overload set for a particular function call.

Question 3

What is constexpr if?

Answer

constexpr if is a compile-time version of the if statement. The syntax for it is if constexpr(condition). It’s...