Advanced C++ Programming Cookbook

How it works...

In this recipe, we will learn how to add std::mutex to a class's private members while still being able to handle const scenarios. Generally speaking, there are two ways to ensure an object is thread-safe. The first method is to place std::mutex at the global level. Doing this ensures an object can be passed as a constant reference or the object itself can have a function marked as const.

For this, consider the following code example:

#include <mutex>#include <thread>#include <iostream>std::mutex m{};class the_answer{public:    void print() const    {        std::lock_guard lock(m);        std::cout << "The answer is: 42\n";    }};int main(void){    the_answer is;    is.print();    return 0;}

In the preceding example, we create an object that outputs to ...