Getting You There - Your C++ Standardization Efforts in 2019

by JeanHeyd Meneide

If you’re facing Financial Hardship, are a student, are self-employed, and have written a proposal that the chairs of the C++ Standardization Groups (Library Evolution, Evolution, Core, Library, Parallelism/Concurrency, and similar study groups) deem necessary to help move the language forward (in large or small ways), you can apply for Grant Assistance from the C++ Standards Foundation. If you have an employer but that employer will not cover the full cost, you have papers to present (yours or on behalf of others) and similar, you can apply for Travel Assistance.

I will talk about Travel Assistance, because that is what I have applied for and successfully received. A huge thanks to the Standard C++ Foundation for making something like this available! I can only hope that my work will continue to be things that they need, and that I can continue to write papers and do work on behalf of the C++ Community to move our various industries forward...

REPL (Read-Eval-Print-Loop) in C++: hands-on session

by Pascal Thomet

A Read-Eval-Print-Loop (REPL) enables to leverage very rapid and robust application development, prototyping and testing. This kind of development environment originates from the early days of functional programming (Lisp machines and the like), and is common in functional and scripting languages.

As a compiled language, C++ was out of the loop for a long time...

A Simple Timer in C++

by Jonathan Boccara

Some languages, such as JavaScript or Visual Basic, offer the feature of a timer, that is to say an object that calls some code at defined intervals. At the time of this writing (C++17) and to my knowledge, C++ doesn’t offer such a feature...

What is an Allocator?

by Vanand Gasparyan

This is one of the many beautiful questions you can think on or be asked at interviews if your native coding language is C++. The beautiful thing about this question is that you answer it again and again as you grow and gain more experience. Similarly, when you’re being interviewed for an internship, knowing that there is such a thing somewhere in STL might be enough, whereas later you’ll be expected to write your own custom allocator...

Don’t forget: std::pair does lexicographical ordering, so you don’t have to

by Raymond Chen

A feature perhaps not as widely known as I thought is that the std::pair type performs lexicographical ordering, so you don't have to...

C++, C# and Unity

by Lucas Meijer

C++ is not great at this task. I want my loop to be vectorized, but a million things can happen that might make the compiler not vectorize it. It might be vectorized today, but not tomorrow if a new seemingly innocent change happens. Just convincing all my C/C++ compilers to vectorize my code at all is hard.

Ranges, Code Quality, and the Future of C++

by Jason Meisel

Many of you have seen the recent blog post by Eric Niebler about the acceptance of his C++ Ranges proposal to the C++2a standard. This is a feature set I’ve wanted in C++ for some time. In fact, using C#’s standard LINQ library, I’ve become accustomed to writing code in this style.

I found it unfortunate, then, to see people respond to this post on Reddit and Twitter by complaining that this feature makes code unreadable. Apparently, C++ is becoming more complex and less useful.

I think this is completely untrue. C++2a is going to be the best version of C++ yet, and a big reason for that is Eric’s Ranges library.

But even to me, his Pythagorean Triples example is bad code. This is not because this range library makes code harder to read, but because he utilizes the library very poorly...

A Free Ebook on C++ Smart Pointers

by Jonathan Boccara

To write expressive code in C++, mastering smart pointers is a necessity! Without them, our code becomes littered with memory management, news and delete, and unclear semantics about who owns what resources.

If you’re part of my mailing list (which you can join at the bottom of this post), you will get as a Christmas gift a free ebook of more than 50 pages of selected contents of Fluent C++ about smart pointers. Of course, you also get access to the ebook if you’re a Patron of Fluent C++...

The SoA Vector – Part 2: Implementation in C++

by Sidney Congard

Like we saw in the first part of this series on SoA, the SoA is a way to organise the data of a collection of objects to optimise the performance of certain use cases: traversing the collection by accessing the same data member of all the objects:

struct person {
   std::string name;
   int age;
};

std::vector<person> persons = ...

for (auto& person : persons)
{
   ++person.age;
}
struct person {
   std::string name;
   int age;
};

std::vector<person> persons = ...

for (auto& person : persons)
{
   ++person.age;
}

The SoA in its barest expression is this:

struct persons {
    std::vector<std::string> names;
    std::vector<int> ages;
};
struct persons {
    std::vector<std::string> names;
    std::vector<int> ages;
};

By putting all the ages next to each other in memory, we optimise the performance of the traversal. But such a structure is not a container in itself, and is in particular not compatible with the STL.

Let’s design an SoA collection with an interface as close as possible to std::vector<persons>, but with the SoA structure of components stored in separate arrays...

C++ ... in 2018

by Bartłomiej Filipek

2018 is almost over (just a few hours left in Poland till midnight). As in previous years, I did a summary of many things that happened in the C++ community. This year seems to be marked with a solid progress towards the standardisation of C++20, using more and more C++17 and as always the growth in the community.

Let’s have a look...