Book Image

C++20 STL Cookbook

By : Bill Weinman
Book Image

C++20 STL Cookbook

By: Bill Weinman

Overview of this book

Fast, efficient, and flexible, the C++ programming language has come a long way and is used in every area of the industry to solve many problems. The latest version C++20 will see programmers change the way they code as it brings a whole array of features enabling the quick deployment of applications. This book will get you up and running with using the STL in the best way possible. Beginning with new language features in C++20, this book will help you understand the language's mechanics and library features and offer insights into how they work. Unlike other books, the C++20 STL Cookbook takes an implementation-specific, problem-solution approach that will help you overcome hurdles quickly. You'll learn core STL concepts, such as containers, algorithms, utility classes, lambda expressions, iterators, and more, while working on real-world recipes. This book is a reference guide for using the C++ STL with its latest capabilities and exploring the cutting-edge features in functional programming and lambda expressions. By the end of the book C++20 book, you'll be able to leverage the latest C++ features and save time and effort while solving tasks elegantly using the STL.
Table of Contents (13 chapters)

Use std::async for concurrency

std::async() runs a target function asynchronously and returns a std::future object to carry the target function's return value. In this way, async() operates much like std::thread but allows return values.

Let's consider the use of std::async() with a few examples.

How to do it…

In its simplest forms, the std::async() function performs much the same task as std::thread, without the need to call join() or detach() and while also allowing return values via a std::future object.

In this recipe, we'll use a function that counts the number of primes in a range. We'll use chrono::steady_clock to time the execution of each thread.

  • We'll start with a couple of convenience aliases:
    using launch = std::launch;
    using secs = std::chrono::duration<double>;

std::launch has launch policy constants, for use with the async() call. The secs alias is a duration class, for timing our prime number calculations...