C++ - Reddit

Simple MPSCQueue with explanation

My previous post got deleted because It seems like AI detector has disliked the "polished" style of the post. I guess it should be rewritten in a more "casual" way, with grammar errors. Sorry for duplication if anyone has seen this already.

\----
During my free time, I have stumbled upon such segment of C++ as "low latency" and "lock free". This topic has initially fascinated me so much, because I couldn't have even imagined that some thing like this could even exist, and is actively used in a very interesting and specific segment of the market... But that is a story for another time :)

I have decided to get familiar with the topic, and as my first step, I wanted to implement something. I have chosen MPSC (Multiple Producer, Single Consumer) queue, but I've quickly realised that the entry barrier is overly high. I literally had no understanding of where I could start.

I spent several weeks gathering knowledge bit by bit, studying advanced multithreading, atomics, memory ordering, and lock-free algorithms. Finally I came up with something I want to share here.

I thought it would be valuable to create a detailed walkthrough, which can be used either by me in future, when I get back to this in maybe several month or years, my friends who would love to learn about this topic, or anyone else who would find themselves in a situation like this.

This project is for sure not the best, not ideal, and not something universe-changing. It is just a "school-grader-level" project with the explanation, hopefully understandable to the same "school-grader".

I, personally, would have loved to have an article like this while I was learning, since it could save at least several weeks, so I hope it helps others in the same way.

https://github.com/bowtoyourlord/MPSCQueue

Any critics welcome.

https://redd.it/1p2bizu
@r_cpp

I tried videos... I tried courses...

I tried websites...(yes even learn CPP website) i tried audiobooks... i tried spotify... I even tried 2 different LLMs...

And in the end... I bought a physical book...

"C++ All In One for Dummies by John Paul Mueller"

This is the best $50 I have ever spent.(I probably spent over $100 on tutorials alone) I've probably watched hundreds of hours of tutorials through video and listening and following along and none have helped me understand the concepts, each individual character and it's placement. I spent all day running around to book stores yesterday to find it and got a last copy physically available at a Barnes and Noble.(Recomended for absolute beginners with easy reading) After skimming through it in the book store I KNEW I had it!

I know everyone learns differently but I've taken this with me when I go out driving and open it up when I'm on break or have down time.

Now, I know it ain't C++ primer 5th edition but I'm already past page 100 and have a much better time recalling information. If you're struggling to learn C++ or programming in general heres my advice(super limited) that I learned earlier this week when googling: Why is it so hard to learn this stuff? Especially when I'm very good at following logic in conversation or methodology. I should be able to translate that basic understanding into a new language that's just as explicit right?

What I discovered was something so obvious yet bold. A few different reddit posts with other people struggling to learn their own various programming languages. (Which i will grab the links to later if you REAAALLY need sources)

The commentary on those posts is summarized as follows:

Turn off the videos. Turn off the tutorials. Turn off the LLMs. Turn off your computer. Turn off your phone.

Open a book, sit down, and learn the hard way.

Between you and me, it has been a PEHNOMINAL GAME CHANGER after only a day and a half of just sitting down, reading, and thinking about the context. Flipping back and forth from page to page to rediscover and refresh how one topic blends into the next.

I hope this helps someone else out there. :)

Ps: Any 'pointers' 😉 from the cpp community for someone who's excitement to learn cpp has been reignited?

https://redd.it/1p2cbxn
@r_cpp

2025"**](https://youtube.com/watch?v=EyTSuFJ0Too&utm_source=techtalksweekly&utm_medium=email) ⸱ **+100 views** ⸱ 19 Nov 2025 ⸱ 01h 06m 11s tldw: A practical tour of C++ command-line tooling with demos that shows when compilers, linkers, and other old-school tools beat IDEs and why it's worth learning.

# ACCU 2025

1. [**"The Past, Present and Future of Programming Languages - Kevlin Henney - ACCU 2025"**](https://youtube.com/watch?v=8-3QwoAmyuk&utm_source=techtalksweekly&utm_medium=email) ⸱ **+3k views** ⸱ 14 Nov 2025 ⸱ 01h 30m 21s tldw: See how programming languages encode ways of thinking, why progress feels slow, and how trends like FOSS and LLMs might reshape code, definitely worth watching for everyone.
2. [**"The Definitive Guide to Functional Programming in Cpp - Jonathan Müller - ACCU 2025"**](https://youtube.com/watch?v=lvlXgSK03D4&utm_source=techtalksweekly&utm_medium=email) ⸱ **+1k views** ⸱ 16 Nov 2025 ⸱ 01h 09m 26s tldw: Functional programming in C++ is actually practical with the modern standard library, covering std::ranges, composable error handling with std::optional and std::expected, algebraic data types, separating IO from computation, and yes the M-word, worth a watch.
3. [**"What C++ Needs to be Safe - John Lakos - ACCU 2025"**](https://youtube.com/watch?v=6-MrKxsR__I&utm_source=techtalksweekly&utm_medium=email) ⸱ **+600 views** ⸱ 19 Nov 2025 ⸱ 01h 31m 24s tldw: With governments pushing memory-safe languages, this talk maps concrete technical proposals, like Contracts, handling erroneous behavior, and Rust-like checked relocation, that could realistically make C++ safe again and is worth watching.

# CppNorth 2025

1. [**"Lightning Talks - CppNorth 2025"**](https://youtube.com/watch?v=V5kgi0gfh7M&utm_source=techtalksweekly&utm_medium=email) ⸱ **+100 views** ⸱ 17 Nov 2025 ⸱ 01h 52m 16s tldw: -

# Podcasts

1. [**"Episode 260: 🇳🇱 C++ Under the Sea 🇳🇱 Ray, Paul, Parrot & Scanman!"**](https://feeds.buzzsprout.com/1501960.rss?utm_source=techtalksweekly&utm_medium=email) ⸱ *ADSP (Algorithms + Data Structures = Programs)* ⸱ 14 Nov 2025 ⸱ 00h 24m 11s tldl: A deep dive into C++ under real GPU workloads explores scans, Parrot, and modern parallel patterns in a way that makes you want to rethink how you write high-performance code.

Please let me know what you think about this format in the comments. Thank you 🙏

https://redd.it/1p26od7
@r_cpp

C++ Podcasts & Conference Talks (week 47, 2025)

Hi r/cpp!

As part of [Tech Talks Weekly](https://www.techtalksweekly.io/), I'll be posting here every week with all the latest C++ conference talks and podcasts. To build this list, I'm following over [100 software engineering conferences](https://www.techtalksweekly.io/i/170091550/conferences) and even more podcasts. This means you no longer need to scroll through messy YT subscriptions or RSS feeds!

In addition, I'll periodically post compilations, for example a list of the most-watched C++ talks of 2025.

The following list includes all the C++ talks and podcasts published in the past 7 days (2025-11-13 - 2025-11-20).

Let's get started!

# Podcasts

# CppCon 2025

1. [**"Concept-based Generic Programming - Bjarne Stroustrup - CppCon 2025"**](https://youtube.com/watch?v=VMGB75hsDQo&utm_source=techtalksweekly&utm_medium=email) ⸱ **+15k views** ⸱ 14 Nov 2025 ⸱ 01h 23m 29s tldw: You'll learn about concept-based generic programming with practical examples, including a tiny type system that prevents narrowing and enforces range checks and walks through design rationale, relations to OOP, and C++26 static reflection, worth watching if you write generic C++.
2. [**"Implement the C++ Standard Library: Design, Optimisations, Testing while Implementing Libc++"**](https://youtube.com/watch?v=iw8hqKftP4I&utm_source=techtalksweekly&utm_medium=email) ⸱ **+3k views** ⸱ 18 Nov 2025 ⸱ 01h 01m 07s tldw: A practical tour of libc++ showing space packing tricks, wait and iterator optimisations, and rigorous testing techniques that’s worth watching if you care about squeezing performance and correctness out of C++ standard library code.
3. [**"The Evolution of std::optional - From Boost to C++26 - Steve Downey - CppCon 2025"**](https://youtube.com/watch?v=fTbTF0MUsPA&utm_source=techtalksweekly&utm_medium=email) ⸱ **+2k views** ⸱ 17 Nov 2025 ⸱ 00h 59m 49s tldw: See how std::optional evolved from Boost to C++26 to learn why optional references are so tricky, what landed (range support and optional), and how those design tradeoffs reshape sum types, lifetime safety, and everyday C++ code; watch this talk.
4. [**"Could C++ Developers Handle an ABI Break Today? - Luis Caro Campos - CppCon 2025"**](https://youtube.com/watch?v=VbSKnvldtbs&utm_source=techtalksweekly&utm_medium=email) ⸱ **+1k views** ⸱ 19 Nov 2025 ⸱ 01h 03m 19s tldw: This talk asks whether C++ developers could handle an ABI break today, examines libstdc++'s history, common library ABI pratfalls, and how tools like Conan and vcpkg mitigate risk, and argues the pain might be less than we fear so give it a watch.

# Meeting C++ 2025

1. [**"Casts in C++: To lie... and hopefully - to lie usefully - Patrice Roy - Meeting C++ 2025"**](https://youtube.com/watch?v=spxCeWT-GrA&utm_source=techtalksweekly&utm_medium=email) ⸱ **+400 views** ⸱ 15 Nov 2025 ⸱ 01h 11m 37s tldw: This talk explains why we sometimes lie to the compiler, what each cast actually does, when writing your own makes sense, and practical tips to avoid surprises, so watch it.
2. [**"Does my C++ Object Model Work with a GPU and Can I Make It Safe - Erik Tomusk - Meeting C++ 2025"**](https://youtube.com/watch?v=OSGDH_oK2s0&utm_source=techtalksweekly&utm_medium=email) ⸱ **+300 views** ⸱ 13 Nov 2025 ⸱ 01h 01m 25s tldw: This talk answers whether C++'s object model can work with GPUs and be made safe, using code examples, accelerator API design, and hardware details that matter for real time and safety critical systems.
3. [**"Designing an SPSC Lock free queue - Quasar Chunawala - Meeting C++ 2025"**](https://youtube.com/watch?v=mus6djSJLLc&utm_source=techtalksweekly&utm_medium=email) ⸱ **+200 views** ⸱ 17 Nov 2025 ⸱ 00h 56m 55s tldw: A back to basics talk that walks from a mutex and condition variable producer consumer queue through semaphores, atomics, memory ordering, and CAS to a practical lock free SPSC queue, worth watching if you want solid, practical concurrency knowledge.
4. [**"Command Line C++ Development - Mathew Benson - Meeting C++

Do these posix socket functions completely overwrite the addr variable?

In this code snippet I am trying to reuse the addr variable to read multiple socket addresses into it under the assumption that functions like getsockname, getpeername *completely* overwrite the `addr` bits. Is my assumption correct? I am trying to reuse my variables here instead of creating new ones.



int main(int argc, char **argv) {

int fd = socket(AF_INET, SOCK_STREAM, 0);

if (fd < 0) {

die("socket()");

}



struct sockaddr_in addr = {};

addr.sin_family = AF_INET;

addr.sin_port = htons(1234);

addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

int rv = connect(fd, (const struct sockaddr *)&addr, sizeof(addr));

socklen_t len = sizeof(addr);

unsigned short client_port = 0;

if (!getsockname(fd, (struct sockaddr *)&addr, &len)) {

client_port = ntohs(addr.sin_port);

}

if (rv) {

die("connect");

} else {

socklen_t len = sizeof(addr);

int remote = getpeername(fd, (struct sockaddr *)&addr, &len);

if (remote) {

printf("error getting remote address\n");

} else {

char ip[INET_ADDRSTRLEN];

inet_ntop(AF_INET, &addr.sin_addr, ip, sizeof(ip));

printf("connected to server @ <%s:%d>", ip, ntohs(addr.sin_port));

}

if (client_port != 0 && remote == 0)

printf(" | client port <%d>\n", client_port);

}

const char *data = argc > 1 ? argv[1] : "hello!";

write(fd, data, strlen(data));

char rbuf[64] = {};

ssize_t n = read(fd, rbuf, sizeof(rbuf) - 1);

if (n < 0) {

die("read");

}

printf("server says: %s\n", rbuf);

close(fd);



return 0;

}



https://redd.it/1p25aru
@r_cpp

how to sandbox a c++ child process on MacOSX?

So here is what I want to do:

I have a parent process that is trusted. I want this parent process to run a child process, which is untrusted.

The child can be an arbitrarily sourced script, or just written pooly. I want it run safely, without worrying (too much) about the child "doing bad things".

The child will communicate to it's parent via message-passing, probably via shared-memory.

These child will be a script, in a language that I have made, and run in a VM. However, this VM has access to low-level unix functions, like exec/kill/open/read/write/remove/etc. This is fine for trusted scripts.

But for untrusted scripts, it is not acceptable.

Instead, I want to block access to almost all syscalls. I've seen proposals like disable(): https://www.reddit.com/r/osdev/comments/1mpphmo/adding\_a\_disable\_syscall/ But of course... this does not exist yet.

OpenBSD has a "pledge()" call. But I need this on OSX.

I've heard of `ptrace()`being used to acheive this. I don't know how to do this. Does this work well on MacOSX?

Obviously... the idea is to acheive this workflow:

1. Parent sets up shared-memory for communication
2. Parent calls fork
3. Forked child drops most of the permissions or abilities
4. Forked child calls exec()
5. Exec'd child then has to drop the permission to call exec!
6. Exec'd child finally does the required work

Something like that. That or something simpler that acheives the same goal.

I don't need this immediately, but sometime before 3 months I will want this. But I can start today if I get good info today.

https://redd.it/1p249qy
@r_cpp

I built a small 5G KPI extractor for 5G base station generated logs (c++, no dependecies) as part of 5G Test Automation Project. The core parsing and KPI logic is in place but it still misses an intelligent visualization/dashboard layer
https://github.com/nidalaburaed/5GBTSLogAnalyzer

https://redd.it/1p1z74f
@r_cpp

I am getting compilation error for my old cpp source code in new build envrionment

#define blahblah(SWC_MAJOR_VER, SWC_MINOR_VER) \

{ \

Dt_RECORD_SWC_Identification vSWCinfo = \

{ .DeSWCVersion = { .DeMajor = (SWC_MAJOR_VER), .DeMinor = (SWC_MINOR_VER) }, \

}; \

}



error: expected primary-expression before ‘)’ token .DeSWCVersion = { .DeMajor = (SWC_MAJOR_VER), .DeMinor = (SWC_MINOR_VER) }, \







co-pilot suggested code

#define blahblah(SWC_MAJOR_VER, SWC_MINOR_VER) \

{ \

Dt_RECORD_SWC_Identification vSWCinfo = \

{ { (SWC_MAJOR_VER), (SWC_MINOR_VER) } }; \

}


I am getting compilation error if i use this working code in new build environ ment and i f i use co piot suggested code my build is compiling in new build enviroement

https://redd.it/1p1zaaa
@r_cpp

Simple MPSCQueue with explanation

I wanted to learn about **lock-free programming**. To do that, I decided to implement an **MPSC (Multiple Producer, Single Consumer) queue**, but I quickly realized that the entry barrier is very high—at first, I had literally no idea where to start.

I spent several weeks gathering knowledge bit by bit, studying multithreading, atomics, memory ordering, and lock-free algorithms. Eventually, I was able to come up with an algorithm, implement it, and debug it successfully.

I thought it would be valuable to create a detailed walkthrough, written while the experience is still fresh. My goal is that this can be useful:

* For myself in the future, if I need to revisit lock-free queues.
* For friends or anyone just starting with concurrency.
* For anyone interested in understanding the **basics of low-latency, high-performance, lock-free concepts**.

I would have loved to have an article like this while I was learning, so I hope it helps others in the same way.

[Check out the project on GitHub](https://github.com/bowtoyourlord/MPSCQueue)

Any critics welcome.

https://redd.it/1p1pwp2
@r_cpp

This Rust code was the one responsible for taking the whole damn world offline.

/// Fetch edge features based on `input` struct into [`Features`] buffer.
pub fn fetch_features(
    &mut self,
    input: &dyn BotsInput,
    features: &mut Features,
) -> Result<(), (ErrorFlags, i32)> {
    // update features checksum (lower 32 bits) and copy edge feature names
    features.checksum &= 0xFFFF_FFFF_0000_0000;
    features.checksum |= u64::from(self.config.checksum);
    let (feature_values, _) = features
        .append_with_names(&self.config.feature_names)
        .unwrap();
}

If this solution were still written in C++, what are the chances that this error would have happened?

Considering the code was rewritten, meaning there was already a working solution, was this forced migration from C++ to Rust really a good idea? After all, the world went down because of a human error, but maybe that mistake could have been avoided if the rewrite had never happened.



https://redd.it/1p1jurj
@r_cpp

just questions in my mind

HI all,

which is best for careers even I am asking the recruiters here that

should I do the c++ certification from the cppinstitute or the audacity nanodegree for the c++ here

https://redd.it/1p1e2b2
@r_cpp

Why People doesn’t start to use the newest c++ version right away?

I see many recent versions of cpp. Why people still use 2010ish versions? What does “safe to use” policy mean for a programming language?

https://redd.it/1p1a1wq
@r_cpp

Shared cache acceleration in Visual Studio 26 + Incredibuild

Does the version of Incredibuild that comes with Visual Studio 26 support shared cache acceleration? I have a small team working on a hefty project and we're getting hung up on redundant recompilations.

https://redd.it/1p17rv2
@r_cpp

C++20s concepts with a forward declared type
https://andreasfertig.com/blog/2025/11/cpp20s-concepts-with-a-forward-declared-type/

https://redd.it/1p18191
@r_cpp

GCC Developer Discovers "Our Codebase Isn't Fully C++20 Ready"
https://www.phoronix.com/news/GCC-Fix-CPP20-Build-Issues

https://redd.it/1p17zif
@r_cpp

STL reimagined: What would you change, add or remove in a new STL implementation if API and ABI were not a concern?

Hello everyone,

I was just curious as to what would make a better STL if it was written today.

Things that come to mind immediately for me:

- Associative containers should not have const keys.
- Probably only emplace back, no push back.
- iterators escape and are unsafe.
- probably only a range abstraction that uses indexes like in Flux?
- allocators, according to Sean Parent, violate the whole/part principle, maybe memory allocationshould go out of containers?
- allocators should not be part of the type at all?
- only allocators for bytes?
- unordered containers should use linear probing.
- There should be some higher-level type-erased non-inteusive interfaces for containers?
- algorithms should admit only ranges.
-how about having Python-style container slicing in vector?
- library would not contain UB interfaces and fewer escape hatches and more difficult to misuse.


What do you think you would add/remove/modify?

https://redd.it/1p120w9
@r_cpp

[C++ Day 2025] Interactive Program Design in C++ (Massimo Fioravanti)
https://www.youtube.com/watch?v=-yHseDKXzvg

https://redd.it/1p13lyt
@r_cpp

PlutoBook is a robust HTML rendering library tailored for paged media. It takes HTML or XML as input, applies CSS stylesheets, and lays out elements across one or more pages, which can then be rendered as Bitmap images or PDF documents

https://github.com/plutoprint/plutobook

https://redd.it/1p12xey
@r_cpp

Already end of year 2025, still C++23 import does not work in most platforms.

this is so frustrating.

https://redd.it/1p1118u
@r_cpp

Latest News From Upcoming C++ Conferences (2025-11-18)

This Reddit post will now be a roundup of any new news from upcoming conferences with then the full list being available at https://programmingarchive.com/upcoming-conference-news/

OPEN CALL FOR SPEAKERS

C++Online 2026 – LAST CHANCE – Accepting Submissions from Speakers Across the Globe, for online talk sessions. New speakers welcomed. Interactive or non-standard sessions also encouraged.
Interested speakers have until November 21st to submit their talks which is scheduled to take place on 11th – 15th March. Find out more including how to submit your proposal at https://cpponline.uk/call-for-speakers/
(NEW) ACCU on Sea 2026 – Interested speakers have until January 11th to submit their talks which is scheduled to take place on 17th – 20th June. Find out more including how to submit your proposal at [https://accuconference.org/callforspeakers](https://accuconference.org/callforspeakers)

OTHER OPEN CALLS

There are no other open calls at the moment

TICKETS AVAILABLE TO PURCHASE

The following conferences currently have tickets available to purchase

ACCU on Sea (15th – 20th June) – You can buy super early bird tickets at https://accuconference.org/booking with discounts available for ACCU members.

OTHER NEWS

(NEW) Meeting C++ 2025 Conference YouTube Videos – Last week the Meeting C++ Conference took place and videos from that conference will start being released soon. Subscribe to the Meeting C++ YouTube channel to stay up to date when videos start releasing. [https://www.youtube.com/c/MeetingCPP](https://www.youtube.com/c/MeetingCPP)
(NEW) ADC25 Conference YouTube Videos – Last week the ADC Conference took place and videos from that conference will start being released in 2026. Subscribe to the ADC YouTube channel to stay up to date when videos start releasing. https://www.youtube.com/@audiodevcon
(NEW) CppCon 2025 Videos Now Releasing – The CppCon videos are now being released. Subscribe to the CppCon YouTube channel to be informed when each video is released. [https://www.youtube.com/@CppCon](https://www.youtube.com/@CppCon)
C++Day YouTube Videos Now Releasing – Subscribe to the C++Day YouTube Channel to be informed when new videos are released https://www.youtube.com/@ItalianCppCommunity



https://redd.it/1p0h1z4
@r_cpp