Book Image

Boost C++ Application Development Cookbook - Second Edition

By : Anton Polukhin Alekseevic
Book Image

Boost C++ Application Development Cookbook - Second Edition

By: Anton Polukhin Alekseevic

Overview of this book

If you want to take advantage of the real power of Boost and C++ and avoid the confusion about which library to use in which situation, then this book is for you. Beginning with the basics of Boost C++, you will move on to learn how the Boost libraries simplify application development. You will learn to convert data such as string to numbers, numbers to string, numbers to numbers and more. Managing resources will become a piece of cake. You’ll see what kind of work can be done at compile time and what Boost containers can do. You will learn everything for the development of high quality fast and portable applications. Write a program once and then you can use it on Linux, Windows, MacOS, Android operating systems. From manipulating images to graphs, directories, timers, files, networking – everyone will find an interesting topic. Be sure that knowledge from this book won’t get outdated, as more and more Boost libraries become part of the C++ Standard.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Multiple-readers-single-writer lock


Imagine that we are developing some online services. We have an unordered map of registered users with some properties for each user. This set is accessed by many threads, but it is very rarely modified. All operations with the following set are done in a thread-safe manner:

#include <unordered_map> 
#include <boost/thread/mutex.hpp> 
#include <boost/thread/locks.hpp> 

struct user_info {
    std::string address;
    unsigned short age;

    // Other parameters
    // ...
};

class users_online {
    typedef boost::mutex mutex_t;

    mutable mutex_t                             users_mutex_;
    std::unordered_map<std::string, user_info>  users_;

public:
    bool is_online(const std::string& username) const {
        boost::lock_guard<mutex_t> lock(users_mutex_);
        return users_.find(username) != users_.end();
    }

    std::string get_address(const std::string& username) const {
        boost::lock_guard&lt...