February 10-15, Hagenberg, Austria
March 19-21, Madrid, Spain
April 1-4, Bristol, UK
June 16-21, Sofia, Bulgaria
By Adrien Hamelin | May 13, 2019 10:26 AM | Tags: stl c++17
It's coming!
C++17 STL Parallel Algorithms - with GCC 9.1 and Intel TBB on Linux and macOS
by Paul Silisteanu
From the article:
GCC 9.1 has support for C++17 parallel algorithms by using the Intel TBB library. In this article, I will show you how to build Intel TBB from sources on your machine and how to sort a vector of random numbers in parallel using C++17 std::sort...
By Adrien Hamelin | Mar 12, 2019 11:46 AM | Tags: stl c++17
Do you need them?
STL Algorithms on Tuples
by Jonathan Boccara
From the article:
When you manipulate a collection of objects in C++–which is quite a common thing to do when programming in C++–STL algorithms are your loyal companions to perform operations with expressive code.
But the STL algorithms, shipped in the standard library with C++, only apply to collections that are filled at runtime, during the execution of a program (or in C++20, during the execution of constepxr code during compilation). This include the ubiquitous std::vector and std::map.
But STL algorithms don’t operate on std::tuples.
However, it could be useful to iterate over the elements of a tuple, at runtime, and perform transformations or extract information, like STL algorithms do. We will see in detail a situation where this is useful with the demux output iterator, in a future post.
Can we design algorithms that are do what STL algorithms do, but on the contents of std::tuples instead of std::vectors and std::maps?
It turns out we can.
By Adrien Hamelin | Feb 11, 2019 01:03 PM | Tags: stl intermediate
What do you think?
Why You Should Use std::for_each over Range-based For Loops
by Jon Kalb
From the article:
I’d like start by thanking Jonathan for creating and maintaining the Fluent{C++} blog, for the conversations that it spawns, and for letting me contribute with this guest post. Jonathan has invited me to add my thoughts on his previous posting, Is std::for_each obsolete?
By Adrien Hamelin | Aug 1, 2018 12:54 PM | Tags: stl performance
Have you registered for CppCon 2018 in September? Registration is open now.
While we wait for this year’s event, we’re featuring videos of some of the 100+ talks from CppCon 2017 for you to enjoy. Here is today’s feature:
How to Write a Custom Allocator
by Bob Steagall
Summary of the talk:
You'd like to improve the performance of your application with regard to memory management, and you believe this can be accomplished by writing a custom allocator. But where do you start? Modern C++ brings many improvements to the standard allocator model, but with those improvements come several issues that must be addressed when designing a new allocator.
This talk will provide guidance on how to write custom allocators for the C++14/C++17 standard containers. It will cover the requirements specified by the standard, and will describe the facilities provided by the standard to support the new allocator model and allocator-aware containers. We'll look at the issues of allocator identity and propagation, and examine their implications for standard library users, standard library implementers, and custom allocator implementers. We'll see how a container uses its allocator, including when and how a container's allocator instance propagates. This will give us the necessary background to describe allocators that implement unusual semantics, such as a stateful allocator type whose instances compare non-equal. Finally, the talk will provide some guidelines for how to specify a custom allocator's public interface based on the semantics it provides.
By Adrien Hamelin | May 22, 2018 01:04 PM | Tags: stl intermediate
Old vs new.
std::accumulate vs. std::reduce
by Simon Brand
From the article:
std::accumulate has been a part of the standard library since C++98. It provides a way to fold a binary operation (such as addition) over an iterator range, resulting in a single value. std::reduce was added in C++17 and looks remarkably similar. This post will explain the difference between the two and when to use one or the other...
By Adrien Hamelin | May 11, 2018 12:29 PM | Tags: stl intermediate
Do you use them?
Modern C++ Features – std::variant and std::visit
by Arne Mertz
From the article:
std::variant is a library addition in C++17 for sum types, and std::visit is one of the ways to process the values in a std::variant.
By Adrien Hamelin | Apr 20, 2018 12:31 PM | Tags: stl intermediate
Did you know?
How to Reorder A Collection With the STL
by Jonathan Boccara
From the article:
The STL lets you do plenty of things on collections, and one of them is to reorder the elements inside of the collection. Or, said another way, to perform a permutation on the collection.
Inded, moving elements around a collection typically takes a fair amount of complex code to write, involving for loops and iterators. And it is perhaps the area where the STL generates the most spectacular improvements, by encapsulating those complex operations behing meaningful interfaces.
Let’s see what sorts of permutations the STL offers:
- Lexicographical permutations
- Cyclic permutations
- Random permutation
- Reverse
- Checking for permutations
- Other permutations
By Adrien Hamelin | Apr 17, 2018 12:36 PM | Tags: stl intermediate
Did you ever try?
How to Pass a Polymorphic Object to an STL Algorithm
by Jonathan Boccara
From the article:
As we can read in the opening chapter of Effective C++, C++ is a federation of 4 languages:
- the procedural part coming from C,
- the object-oriented part,
- the STL part (following a functional programming paradigm),
- the generic part with templates.
And what’s more, all of those 4 sub-languages are part of one whole: the C++ language. Those 4 paradigms begin united in one language gives opportunities for them to interact – and often, those interactions create interesting situations.
Today we’re focusing on one particular interaction, between the object-oriented model and the STL. There could be multiple forms for this interaction, and the case we will look at is how to pass a polymorphic (that is, having virtual methods) function object to an STL algorithm.
By Meeting C++ | Jan 26, 2018 02:45 AM | Tags: stl performance meetingcpp intermediate functional c++14 c++11
Is a better std::function possible?
Is std::function really the best we can do?
by Lukas Bergdoll
By Adrien Hamelin | Nov 24, 2017 02:16 PM | Tags: stl intermediate
And how back_inserter works.
How to Use the STL With Legacy Output Collections
by Jonathan Boccara
From the article:
When you start using the STL and its algorithms in your code, it’s a bit of a change of habits. And then after a while you get used to it. Then it becomes a second nature. And then even your dreams become organized into beautifully structured ranges that fly in and out of well-oiled algorithms.
And when you reach that point, there is no coming back.
Until the day you come upon an old legacy structure that won’t let itself approached by the elegant and expressive way of coding that STL algorithms have. It’s a terrible encounter, where the beast tries to suck you back into the lengthy and dangerous quicksand of the raw for loops that now seemed so far away...