Book Image

C++17 STL Cookbook

By : Jacek Galowicz
Book Image

C++17 STL Cookbook

By: Jacek Galowicz

Overview of this book

C++ has come a long way and is in use in every area of the industry. Fast, efficient, and flexible, it is used to solve many problems. The upcoming version of C++ will see programmers change the way they code. If you want to grasp the practical usefulness of the C++17 STL in order to write smarter, fully portable code, then this book is for you. Beginning with new language features, this book will help you understand the language’s mechanics and library features, and offers insight into how they work. Unlike other books, ours takes an implementation-specific, problem-solution approach that will help you quickly overcome hurdles. You will learn the core STL concepts, such as containers, algorithms, utility classes, lambda expressions, iterators, and more, while working on practical real-world recipes. These recipes will help you get the most from the STL and show you how to program in a better way. By the end of the book, you will be up to date with the latest C++17 features and save time and effort while solving tasks elegantly using the STL.
Table of Contents (18 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Pushing the execution of tasks into the background using std::async


Whenever we want some code to be executed in the background, we can simply start a new thread that executes this code. While this happens, we can do something else and then wait for the result. It's simple:

std::thread t {my_function, arg1, arg2, ...};
// do something else
t.join(); // wait for thread to finish

But then the inconvenience starts: t.join() does not give us the return value of my_function. In order to get at that, we need to write a function that calls my_function and stores its return value in some variable that is also accessible for the first thread in which we started the new thread. If such situations occur repeatedly, then this represents quite a bunch of boilerplate code we have to write again and again.

Since C++11, we have std::async which can do exactly this job for us and not only that. In this recipe, we are going to write a simple program that does multiple things at the same time using asynchronous...