In this text you’ll learn about a few techniques and experiments with constexpr and constinit keywords. By exploring the string implementation, you’ll also see why constinit is so powerful. What is SSO   Just briefly, SSO stands for Short String Optimization. It’s usually implemented as a small buffer (an array or something similar) occurring in the same storage as the string object.

If you have a class with a regular data member like an integer or string, you’ll get all special member functions out of the box. But how about different types? In this article, we’ll look at other categories of members like unique_ptr, raw pointers, references, or const members. Introduction   In my book on “C++ Initialization” I recently wrote a chapter about so-called non-regular data members.

In September and October, I had the pleasure of running two meetings about C++20 features for my local Cracow C++ User Group! Here are the slides and additional comments from the presentation. The Talk   Initially I did one presentation using my article on smaller C++ 20 features (20 Smaller yet Handy C++20 Features - C++ Stories).

The ISO Committee accepted and published the C++17 Standard in December 2017. In this mega-long article, I’ve built (with your help!) a list of all major features of the new standard. Please have a look and see what we get! Language Features New auto rules for direct-list-initialization static_assert with no message typename in a template template parameter Removing trigraphs Nested namespace definition Attributes for namespaces and enumerators u8 character literals Allow constant evaluation for all non-type template arguments Fold Expressions Unary fold expressions and empty parameter packs Remove Deprecated Use of the register Keyword Remove Deprecated operator++(bool) Removing Deprecated Exception Specifications from C++17 Make exception specifications part of the type system Aggregate initialization of classes with base classes Lambda capture of *this Using attribute namespaces without repetition Dynamic memory allocation for over-aligned data __has_include in preprocessor conditionals Template argument deduction for class templates Non-type template parameters with auto type Guaranteed copy elision New specification for inheriting constructors (DR1941 et al) Direct-list-initialization of enumerations Stricter expression evaluation order constexpr lambda expressions Different begin and end types in range-based for [[fallthrough]] attribute [[nodiscard]] attribute [[maybe_unused]] attribute Ignore unknown attributes Pack expansions in using-declarations Structured Binding Declarations Hexadecimal floating-point literals init-statements for if and switch Inline variables DR: Matching of template template-arguments excludes compatible templates std::uncaught_exceptions() constexpr if-statements SFINAE Tag dispatching if constexpr Library Features Merged: The Library Fundamentals 1 TS (most parts) Removal of some deprecated types and functions, including std::auto_ptr, std::random_shuffle, and old function adaptors Merged: The Parallelism TS, a.

In this short article, I’ll show you several techniques to improve raw loops. I’ll take an example of a reverse iteration over a container and then transform it to get potentially better code. The loop expression is an essential building block of programming. When you iterate over a container in C++20, we have the following options:

In this article, I’ll show another technique that avoids mixing signed and unsigned types. In my article Integer Conversions and Safe Comparisons in C++20 we learned about cmp_* integer comparison functions that allow us to compare various types of integer types. The functions are safe because they help with mixing signed and unsigned types.

Sometimes, If you mix different integer types in an expression, you might end up with tricky cases. For example, comparing long with size_t might give different results than long with unsigned short. C++20 brings some help, and there’s no need to learn all the complex rules :) Conversion and Ranks   Let’s have a look at two comparisons:

C++ is famous… or infamous for its complex initialization syntax. In this article, I’ll show you around 20 ways to initialize simple std::string variables. Can we somehow make it easier to understand? Default values   Have a look: void foo() { std::string str0; std::string str1 {}; } We have two local variables (with automatic storage duration), str0 is default initialized, while str1 is value initialized.

While there are many code analysis tools for C++, why not write it from scratch? This article will introduce you to an open-source C++ static analysis tool that you might find useful or at least interesting. This is a guest post from Greg Utas. Greg was chief software architect of the call servers used in AT&T’s wireless network.

Before C++17, we had a few quite ugly-looking ways to write static if (if that works at compile time). For example, you could use tag dispatching or SFINAE. Fortunately, that’s changed, and we can now benefit from if constexpr and concepts from C++20! Let’s see how we can use it and replace some std::enable_if code.

In this blog post I’ll show you a couple of interesting examples with lambda expressions. Do you know how to write a recursive lambda? Store them in a container? Or invoke at compile time? See in the article. Updated in August 2022: Added C++23 improvements. 1. Recursive Lambda with std::function   Writing a recursive function is relatively straightforward: inside a function definition, you can call the same function by its name.

std::format is a large and powerful addition in C++20 that allows us to format text into strings efficiently. It adds Python-style formatting with safety and ease of use. This article will show you how to implement custom formatters that fit into this new std::format architecture. Quick Introduction to std::format   Here’s the Hello World example: