October 25, Pavia, Italy
November 6-8, Berlin, Germany
November 3-8, Kona, HI, USA
By philsquared | Mar 6, 2025 10:13 AM | Tags: None
The ACCU conference has a range of workshops, including online options, this year:
Workshops for Everyone
by ACCU Conference
From the article:
See all the offerings, from Jason Turner, Nicolai Josuttis, Robert Seacord, Gail Ollis, Mateusz Pusz, Phil Nash and Mike Shah.
By philsquared | Mar 6, 2025 10:12 AM | Tags: None
Should you start new projects in C++, these days? Is language safety an issue for you? What can be done, today?
Making C++ Safer
by Greg Law
From the article:
I believe that over time C++ will become a lot safer, maybe even some kind of ‘safe’. Competition is good: Clang was the best thing to happen to GCC, and Rust might turn out to be the best thing to happen to C++. That journey has already begun, with proposals for the evolution of the language including Contracts and Profiles, and simply changing some of the defaults in C++26. While the language custodians work to make the language itself safer, what can you do today?
By Blog Staff | Mar 3, 2025 12:48 PM | Tags: None
When using std::atomic<std::shared_ptr<T>>, the C++ standard defines a "change" as a modification to either the stored pointer or the control block pointer. However, since atomic wait mechanisms typically track only a single memory address, the Microsoft implementation handles this limitation by using a timeout-based polling strategy to detect changes in the control block.
Inside STL: Waiting for a std::atomic<std::shared_ptr<T>> to change, part 1
by Raymond Chen
From the article:
Like other
std::atomicspecializations,std::atomic<supports thestd::shared_ptr<T>> waitandnotify_*methods for waiting for the value to change and reporting that the value has changed. The definition of “changed” in the C++ language specification is that the value has changed if either the stored pointer or the control block pointer has changed. A shared pointer is implemented as a pair of pointers, butWaitOnAddresscan wait on at most 8 bytes, and unix futexes can wait on only four bytes, so how does this work?¹The Microsoft implementation waits for the stored pointer to change, and the
notify_*methods signal the stored pointer. But wait, this fails to detect the case where the stored pointer stays the same and only the control block changes.std::atomic<std::shared_ptr<int>> p = std::make_shared<int>(42); void change_control_block() { auto old = p.load(); auto empty = std::shared_ptr<int>(); // Replace with an indulgent shared pointer // with the same stored pointer. p.store({ empty, old.get() }); p.notify_all(); } void wait_for_change() { auto old = p.load(); p.wait(old); }
By Blog Staff | Feb 27, 2025 03:50 PM | Tags: None
In this post, we are going to discuss a core language feature proposed by Corentin Jabot and Micheal Park in P2169R4. With the new standard we get a cool unnamed placeholder.
C++26: A Placeholder with No Name
by Sandor Dargo
From the article:
By convention, when we have a variable whose value we don’t want to use or care about, we often name it_. The problem is that with higher warning levels (-Wunused-variable), our compilation might fail because_is unused.
int foo() { return 42; } auto _ = foo(); /* error: unused variable '_' [-Werror,-Wunused-variable] */To avoid this problem, we must mark it
[[maybe_unused]].
By Andrey Karpov | Feb 26, 2025 01:51 PM | Tags: sast qt creator qt pvs-studio misra
PVS-Studio 7.35 has been released. Support for the MISRA C standard, the plugin for Qt Creator 15.x, modified file analysis in Visual Studio, and that's not all.
PVS-Studio 7.35: MISRA C 2023 support, Qt Creator 15 plugin, and more
by Vladislav Bogdanov
From the article:
We've begun work to expand the PVS-Studio's coverage of the MISRA C standard. With the release of 7.35, the first eight diagnostic rules have already been implemented, and more are on the way. The full list of implemented rules is provided below. We plan to cover at least 85% of MISRA C and support the latest version of MISRA C 2023.
By Blog Staff | Feb 25, 2025 03:46 PM | Tags: None
Since its introduction, the constexpr keyword in C++ has steadily evolved with each new standard, becoming an increasingly powerful tool for compile-time computation and optimization. In this article, I’ll share a real-world example of how constexpr helped optimize memory usage and improve performance for an embedded system project, showcasing its potential to transform how we approach C++ programming.
Write More C++ Code Thanks to constexpr
by Andreas Fertig
From the article:
Since the keyword
constexprand its behavior got included in C++, it has been improved in each and every new standard of the language.I'm a big fan of
constexprand am not alone. Jason Turner is also very vocal, having coined the term "constexpr all the things".Well, demonstrating the powers of
constexpris nonetheless something difficult. I know that from my training classes and various consulting contracts. Today, I'd like to share a story from back in time when a customer hired me to consult. They did develop an embedded system and ran out of memory. Not during run-time, but before. The features they wanted to put in the chip were too big in code size and somewhat RAM.Initial
constexpr-free exampleThey used a class I've seen a couple of times in embedded systems with some variations. A string brings its memory picky-back.
By Blog Staff | Feb 21, 2025 03:41 PM | Tags: None
Sometimes, we all need a way to iterate over a container in the opposite direction. There are several ways to reverse-iterate a container, and in this article, we’ll explore them.
Reverse Iterations
by Coral Kashri
From the article:
Probably the simplest way, taken from C is to iterate using an index location:
for(int64_tindex = ssize(container); index >= 0; --index) {// do something with `container[index]`}
This way is highly not recommended as it might lead to infinite loops if done incorrectly (for example by usinguint64_torsize_tfor the index type), and you can find more issues with this way in some previous articles about iterators in this blog.
By Blog Staff | Feb 19, 2025 03:38 PM | Tags: None
C++26: user-generated static_assert messages
by Sandor Dargo
From the article:
Our first quest into the world of C++26 was about
=deletewith an optional error message, which improves the readability of the source code and potentially the error messages. In this next part of our journey, we will continue to focus on readability improvements, particularly those for error messages.With C++26 and the acceptance of P2741R3, we are getting better error messages for
static_assert. Compile time assertions were introduced in C++11 with a mandatory message. Since C++17, the message is only optional. And with C++26,static_assertevolves further and the message can be a constant expression instead of an unevaluated string. In other words, it can have some dynamic elements.This was not the first attempt to make such a feature part of C++, but back in 2014, when something similar was proposed, C++ didn’t have enough compile-time programming capabilities to make this easily implementable.
Why is this change useful?
Before looking at some concrete examples of utilisation, let’s dig into the motivations behind this feature.
Obviously, we want better error messages. C++ is infamous for its horrendous error logs when the compilation fails. Even though we must admit that it’s more and more just a legacy, the situation improved a lot over the course of the years. In any case, it was mostly template-related error messages that were behind the biggest issues.
While compile-time assertions with their custom messages already meant an improvement, user-generated diagnostic messages will further improve the situation.
But that’s not the only motivation. Sometimes you don’t want different, or better messages. You just want the same message in several assertions without having to duplicate it. Without this change, the following piece of code doesn’t compile:
By Meeting C++ | Feb 18, 2025 03:23 AM | Tags: training meetingcpp community
With the success of the trainings after Meeting C++ 2024, I've decided to offer more opportunities for you to learn C++. Klaus Iglberger starts next week with C++ Software Design.
With these trainings following in March:
Generic programming in C++ with templates and auto with Nicolai Josuttis (10th March, 1 day)
Embedded C++ Basic Training with Richard Kaiser (10th March, 4 days)
C++ Fundamentals You Wish You Had Known Earlier with Mateusz Pusz (13th March, 2 days)
Concepts, Ranges, and Views - The New Way of Programming in C++ with Nicolai Josuttis (17th March, 1 day)
Introduction to C++ - Five Day Online Training with Slobodan Dmitrovic (24th March, 5 days)
Structured Concurrency in C++: A Hands-On Workshop (Coroutines + Senders/Receivers) with Mateusz Pusz (24th March, 2 days)
My goal is to offer a good set of trainings within a certain time frame each quarter with changing trainers. Ideally all within one week, but that doesn't match out all the time.
By Blog Staff | Feb 17, 2025 03:37 PM | Tags: None
In this article, you’ll see eight larger examples that illustrate the changes in C++23.
8 More C++23 Examples
by Bartlomiej Filipek
From the article:
C++23 brings a ton of cool features, as you can see in my two previous articles (here and here). So far, we explored each new addition one by one, but I’d like to share more examples that combine multiple features.
Here we go:
1.
std::ranges::to<>The
ranges::to<>feature allows you to convert ranges into containers easily:
