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 Be sure that knowledge from this book won’t get outdated, as more and more Boost libraries become part of the C++ Standard.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

Getting a function's result type at compile time


Many good features were added to C++11 to simplify the metaprogramming. One such feature is the alternative function syntax. It allows deducing the result type of a template function. Here is an example:

template <class T1, class T2>
auto my_function_cpp11(const T1& v1, const T2& v2)
    -> decltype(v1 + v2)
{
    return v1 + v2;
}

It allows us to write generic functions more easily:

#include <cassert>

struct s1 {};
struct s2 {};
struct s3 {};

inline s3 operator + (const s1& /*v1*/, const s2& /*v2*/) {
    return s3();
}

inline s3 operator + (const s2& /*v1*/, const s1& /*v2*/) {
    return s3();
}

int main() {
    s1 v1;
    s2 v2;

    s3 res0 = my_function_cpp11(v1, v2);
    assert(my_function_cpp11('\0', 1) == 1);
}

But, Boost has a lot of functions like these and it does not require C++11 to work. How is that possible and how can we make a C++03 version of the my_function_cpp11 function?

Getting ready...