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By Adrien Hamelin | Sep 17, 2020 11:01 AM | Tags: c++20
New library type.
std::span in C++20: Bounds-Safe Views for Sequences of Objects
by Rainer Grimm
From the article:
In my seminar, I often hear the question: How can I safely pass a plain array to a function? With C++20, the answer is quite easy: Use a std::span...
By Adrien Hamelin | Sep 17, 2020 10:57 AM | Tags: c++20
Not so easy, but still useful.
Concept archetypes — update
by Andrzej Krzemieński
From the article:
An observant reader indicated that in the previous post where I was trying to implement a concept archetype — a type with minimal interface that models a given concept — I actually failed. This deserves a closer examination...
By Meeting C++ | Sep 16, 2020 05:50 AM | Tags: meetingcpp intermediate experimental community c++14 basics
Working on an old project, it came to my mind that I do this refactoring from one static path to multiple options for the 2nd time this year...
Refactoring from single to multi purpose
by Jens Weller
From the article:
For the second time this year I'm refactoring a program from a single purpose to have two or more modes of operation. Both times the start and end result is similar, just the processing is different. A classic case of using polymorphism.
The first program was a tool to process videos from speakers, find a face and export the subframe around it into a new video. The first mode was a good approach to test it, and gave results for some speakers. The second mode did a complete scan first, and then gave a smoother video for some videos. Still, both modes had to be retained...
By Adrien Hamelin | Sep 15, 2020 11:16 AM | Tags: c++17
variant shows his capabilities.
Replacing unique_ptr with C++17's std::variant a Practical Experiment
by Bartlomiej Filipek
From the article:
Some time ago I wrote about a new way to implement runtime polymorphism which is based not on virtual functions but on std::visit and std::variant. Please have a look at this new blog post where I experiment with this approach on my home project. The experiment is more practical than artificial examples.
See advantages, disadvantages and practical code issues.
By Adrien Hamelin | Sep 3, 2020 12:00 PM | Tags: c++20
Testing custom concepts.
Concept archetypes
by Andrzej Krzemieński
From the article:
Concepts in the form added in C++20 used to be called lite. This is because they do not provide one quite important functionality: having the compiler check if the author of a constrained template is only using operations and types allowed by the constraining concept. In other words, we can say that our template only requires operations A and B to be valid, but we can still use some other operations inside and this is fine with the compiler. In this post we will show how this is problematic, even for programmers aware of the issue, and how to address it with concept archetypes...
By Adrien Hamelin | Sep 2, 2020 12:44 PM | Tags: community
Would you agree?
6 Efficient Things You Can Do to Refactor a C++ Project
by Bartlomiej Filipek
From the article:
I took my old pet project from 2006, experimented, refactored it and made it more "modern C++". Here are my lessons and six practical steps that you can apply in your projects.
Let’s start...
By Adrien Hamelin | Sep 1, 2020 11:13 AM | Tags: intermediate c++11
Quick A: because it prevents moving from the value.
Recently on SO:
Why is const template parameter not a universal/forwarding reference?
Because it is a reference to const. And references to const are not forwarding references...
By Adrien Hamelin | Sep 1, 2020 11:05 AM | Tags: c++20
Many things were improved.
volatile and Other Small Improvements in C++20
by Rainer Grimm
From the article:
Today, I complete my tour through the C++20 core language features with a few small improvements. One interesting of these minor improvements is that most of volatile has been deprecated.
By Meeting C++ | Sep 1, 2020 09:04 AM | Tags: meetingcpp events community
The monthly overview on upcoming User Group meetings for September, again in the COVID-19 online edition.
Online C++ User Group meetings in September 2020
by Jens Weller
From the article:
In September Meeting C++ online will host 3 Events:
Meeting C++ online with Zach Laine
Meeting C++ online conference
Meeting C++ online with Kevlin Henney
By andyg | Sep 1, 2020 07:15 AM | Tags: None
AndyG warns us that if you're upgrading to Visual Studio 2017, you might be incurring some unexpected performance overhead thanks to better noexcept support.
Friendly reminder to mark your move constructors noexcept
by AndyG
From the article:
Since C++11 we have had the
noexceptkeyword, which is a promise that the function will not throw an exception (and if it does, go straight tostd::terminate, do not pass go). noexcept is nice for two reasons:
- The compiler can optimize a little better because it doesn’t need to emit any code for unwinding a call stack in case of an exception, and
- It leads to incredible performance differences at runtime for
std::vector(and other containers, too)