Notebook C++ - Tips and Tricks with Templates


This book is part of a series which is called Notebook C++. The idea is, that most of us have some kind of notes about do's and dont's, how stuff works, or tips and tricks to keep in mind. It is probably one of the most frequent questions I get during training classes. I have such a list too. In this series, I will publish mine.

My idea is to create multiple short books (ok what is the number of pages required to call it a book or short?) about various topics. Currently, I plan to share tips about templates (this book), lambdas, and trap-like situations like dangling references. There will probably be more. They are available for early birds on Leanpub, however, later they will also be available as a printed version.

Why several short books and not a single large one? Simply to give you a choice. Maybe you are already fine with one topic but have an interest in tips for another topic. Why then by a large book where you need only a portion of it? Another thing is, I personally like printed books. There I find smaller ones more comfortable when carrying them around like in a train or airplane. Plus they are not that heavy then, which is also a plus.

Stuttgart, January 2020

Andreas Fertig

Table of Contents

  • Contents
  • Notes by Standard at a Glance
    • Notes belonging to C++11
    • Notes belonging to C++17
    • Notes belonging to C++20
  • Tips and Tricks with Templates
    • Note 1: Know the name
    • Note 2: Templates can have type and non-type parameters
    • Note 3: When to use typename, when class
    • Note 4: The parts of a variadic template
    • Note 5: There are no implicit conversions for template parameters
    • Note 6: Alias template for clean TMP
    • Note 7: Variable template for clean TMP
    • Note 8: The trailing-return-type with decltypeand void()
    • Note 9: Use declvalwhen you need to construct a type for testing during compile-time
    • Note 10: What void_tdoes
    • Note 11: Keep that array's size
    • Note 12: There is no else if in C++
    • Note 13: More useful than it appears: always_false
    • Note 14: Prefer autoas NTTP to reduce redundancy
    • Note 15: Block template argument deduction
    • Note 16: Fold expressions and the comma operator
    • Note 17: Poor men's fold expressions
    • Note 18: From an array to a pack
    • Note 19: From an array to a pack with templated lambda
    • Note 20: Create objects in place for direct use
    • Note 21: Guidelines for efficient use of templates
    • Note 22: Put enable_ifon the return type
    • Note 23: enable_ifand how to disable a member function
    • Note 24: How to disable a special member function
  • Acronyms
  • Bibliography
  • Index


Table of Contents[ pdf ]


I'm always interested in issue reports or suggestions for improvements.

I like to thank every reader who pointed errors out.

Note 23.3
The example needs to take the `Dummy` parameter in the `enable_if` (which should be `enable_if_t`) and default `Dummy` to the expected return type.