C++20 jthread and stop token: a gentle introduction

Introduction

In my previous article on std::jthread , I missed a few key and basic points on how C++20 jthread and stop token work together in the way how synchronization works for std::jthread objects with automatic storage duration and how to ensure that a task assigned to std::jthread object completes and how to prevent std::jthread from premature suspension of execution of its task because the function it was called within exited and the destructor on std::jthread object is called:

void foo(){
    std::jthread t_foo{task, taks_param1, task_param2, ...};
    ...
 } //t_foo::~jthread() called, 
   // task execution stops even if it did not finish

If you read the previous article about std::jthread , you already know that it’s an RAII version of std::thread and is safer to use in the sense that when a std::jthread object with automatic storage duration goes out of scope, there is no need to call join method because the destructor of std::jthread calls the join method . But that’s not the only thing the destructor does! It in fact sends a request to stop the execution of the task the std::jthread object is tied to.

In this article I’ll explain how to use std::jthread safely and prevent premature execution of the task and in the process show a simplified implementation of…