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Best condensed resource for C++xx > 17 features
I am fairly seasoned in writing C++ up until 11-14. However, I would like to learn some of the more recent feature additions in the standard that came in C++17 and beyond. Any recommendation on a resource/site that has all these features laid out in a nice to consume, concise format would be very helpful.
https://redd.it/1hxp30p
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C++ Printer Library
Does anybody know any C++ printer abstraction libraries? Physical printers to be specific, not outputting to the terminal. The internet is proving pretty useless trying to find this.
https://redd.it/1hxkrih
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C++ SVG graph
I have a c++ code that allows me to set countries and borders using a matrix, it comes down to a graph.I can set a number of colors and withc colors. My code gives each country a color in such a way that if 2 countries are neighbours(they hve a border) they cant have the same color using Greedy coloring algorithm.I want now to show this graph by using a SVG file but i don't know how because i use VS Code, and the project must be set to a docker image and it must run using CMD only so how can i make this svg file work for any inputs and after i run it on CMD with docker run -it ssmth smth how do i get the svg link to open in browser
https://redd.it/1hxfshq
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How to get lldb on windows to show correct format on std containers (and other std related data)?
Hello all,
I am using clang via llvm-msvc, where it is always using msvc stdlib. I couldn't manage to change to clang's stdlib in cmake. Getting debugger working has been pretty challenging. starting from mismatch of python version on downloaded code. (lldb-dap is crashing, codelldb works).
I have been unable to get the containers such as vector to show correctly. Seems I'll need to have custom formatters. Are there any for msvc std that I can use? How do you go with deciphering msvc's std containers to write the synthProviders?
A more general question, How do you setup your llvm toolchain in windows? . What do you use for debugging? Please do share your tips and knowledge as most of the information I meet online is non c++ or non windows when it comes to llvm (as a fallback to msvc debugger is an easy solution)
To answer my own question: As a workaround I am using llvm compiled via minigw, and then I can debug stdlib correctly via codelldb extension. lldb-dap still crashes!
https://redd.it/1hx949d
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Sandor Dargo's Blog - C++26: a placeholder with no name
https://www.sandordargo.com/blog/2025/01/08/cpp26-unnamed-placeholders
https://redd.it/1hx6zke
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In C99, memory allocation for a struct includes its size plus the size of its last member's type, enabling a flexible array member. A colleague called this 'Elastic Struct,' but I found no official term. Is there a recognized name for this technique in C99?
https://redd.it/1hwvbn8
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if constexpr vs overloads
What should a C++ programmer choose by default: if constexpr for every type in one function or function overloads for every type with 2x more boilerplate code, but with ability to easier make a custom override later?
https://redd.it/1hwqxgy
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Streaming (de)serialization and (de)compression in C++
Hi, I wanted to know options in C++ for streaming (de)serialization and (de)compression. Currently, I'm using cereal along with command line zstd tool for this purpose.
Any better methods would be appreciated. Thanks.
https://redd.it/1hwmy4y
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Pipeline architectures in C++ - Boguslaw Cyganek - Meeting C++ 2024
https://www.youtube.com/watch?v=6UYXSu_9dXI
https://redd.it/1hwjlt5
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When was your first memory?
I can literally only remember things from when I was 6 and onwards. Anyone I know who had a great upbringing say they remember from 3 and onwards.
I think trauma has suppressed a lot of my memories. But hearing others say they remember things from such an early age is a big reminder of the trauma.
https://redd.it/1hwawck
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Can we initialize and fill a (flat) hashmap in bulk?
I have a compute shader that quickly generates a buffer of uint32's which is send back to the CPU, this data won't update so it is static.
I require it to be in a hashmap because it is sparse and need fast lookups.
The issue I have is that inserting the items from the buffer into the hashmap directly is slow. I use ankerl::unordereddense which is a flat hashmap, where the api is the same as std::unorderedmap. Is it possible to initialize this hashmap in one go efficiently, for example pre computing the buckets on the GPU and somehow assigning that to the hashmap?
https://redd.it/1hw50nx
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How to Properly Generate compilecommands.json for a C++ Project Using CMake and Bear
I’m trying to generate a `compilecommands.json file for [this project](https://github.com/ReactiveX/RxCpp) to use tools like clangd and clang-format. Here's what I've tried so far:CMAKEEXPORTCOMPILECOMMANDS=ON` in both the root and subdirectory `CMakeLists.txt`.
1. Setting
2. Running `cmake` like this:
mkdir build
cd build
cmake .. -DCMAKE\EXPORT_COMPILE_COMMANDS=ON
3. Using Bear to capture the build process:
bear -- cmake --build .
(EDIT: I used bear without cmake to avoid overriding the json file).
Despite this, compile_commands.json is either not generated or not usable (has [\] inside it).
Any guidance or suggestions would be greatly appreciated!
clang version: 18.1.8
cmake version: 3.31.3
https://redd.it/1hvxexe
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Parsing JSON in C & C++: Singleton Tax
https://ashvardanian.com/posts/parsing-json-with-allocators-cpp/
https://redd.it/1hvug61
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Information
Hi guys, I’m pursuing a PhD in Mathematical Finance and I would like to learn C++ for financial applications, because a friend of mine works in the financial engineering research section of a really important bank and they use it for modelling. I would like to mention that I already have knowledge of Java and OOP, so I would like to ask for some material if you have any recommendations, because I don’t find anything online.
Thanks in advance 😊😊.
https://redd.it/1hvo4s1
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Is C++ worth it?
Greetings all, I have dedicated the next two months for intense c++ programming. I will be following learncpp to learn Cpp 🤡 ( I am open to suggestions for free courses, youtubers or any other websites )But I am concerned, I may or may not finish it but once the two months are done I don't want to regret dedicating it for a language that is not useful
So here is my question, Will C++ remain in demand as much as it is now? Is it wasteful to do cpp over other domains?
I look forward for your replies. Please keep in mind I am only trying to learn and improve not trying to dishonour the programming language, I am genuinely concerned for my future. Quick Help appreciated.
https://redd.it/1hvl2uw
@r_cpp
Why do you prioritize memory safety over performance?
One of the main reasons people use C++ over languages like Python or Java is its fine-grained control over memory, resulting in minimal runtime overhead. This makes C++ one of the most viable options for performance-critical applications like video games.
However, introducing memory safety features like smart pointers often leads to bloated memory usage and runtime overhead, especially with something like std::shared_ptr. Why not simply use the new and delete keywords? In my experience, avoiding memory leaks and dangling pointers isn’t that difficult with proper management.
And if memory safety is your priority over performance, why not use a language like Rust, which automatically ensures memory safety at compile time while having only a slight runtime overhead?
Disclaimer: I’m not that advanced in C++ programming; I’m just curious to hear some other opinions of more experienced C++ developers.
https://redd.it/1hxq181
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Automated test generation
Hi all,
I am wondering if anyone here has used any products or solutions that can auto-generate unit-tests or any tests for that matter for C/C++ projects and what has worked vs. didn't work for you ?
https://redd.it/1hxhe90
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Experimenting with #embed
I recently learned that both clang and gcc have added support for [N3017](https://en.cppreference.com/w/c/preprocessor/embed) a.k.a `#embed` from C23 so naturally my first reaction was to see how well it works in C++ code.
Given this code sample:
#include <array>
#include <cstdint>
#include <experimental/array>
#include <iostream>
#include <utility>
int main() {
// works
static constexpr char c_char_array[] = {
#embed __FILE__
, '\0'
};
static constexpr unsigned char c_unsigned_char_array[] = {
#embed __FILE__
, '\0'
};
static constexpr std::uint8_t c_uint8_array[] = {
#embed __FILE__
, '\0'
};
static constexpr auto std_make_char_array = std::experimental::make_array<char>(
#embed __FILE__
, '\0'
);
static constexpr auto std_make_unsigned_char_array = std::experimental::make_array<unsigned char>(
#embed __FILE__
, '\0'
);
static constexpr auto std_make_uint8_array = std::experimental::make_array<std::uint8_t>(
#embed __FILE__
, '\0'
);
// doesn't work
// static constexpr std::byte c_byte_array[] = {
// #embed __FILE__
// , '\0'
// };
// static constexpr auto std_to_char_array = std::to_array<char>({
// #embed __FILE__
// , '\0'
// });
// static constexpr auto initializer_list = std::initializer_list<char>{
// #embed __FILE__
// , '\0'
// };
std::cout << &c_char_array;
std::cout << &c_unsigned_char_array;
std::cout << &c_uint8_array;
std::cout << std_make_char_array.data();
std::cout << std_make_unsigned_char_array.data();
std::cout << std_make_uint8_array.data();
return 0;
}
Both [gcc](https://godbolt.org/z/T9YroochP) and [clang](https://godbolt.org/z/19zf5dsWv) support the same usages as far as I tested.
What works:
* `char`, `unsigned char`, `std::uint8_t`
* C-style arrays
* `std::experimental::make_array`
What doesn't work:
* `std::byte`
* `std::initializer_list`
* `std::to_array`
I was most surprised that `std::to_array` doesn't work while `std::experimental::make_array` does, however after further investigation it seem likely that if `std::initializer_list` worked with `#embed` then `std::to_array` would as well.
It's not surprising that a C23 standard doesn't work with `std::byte` however if/when a C++ version of this paper gets added to the standard I hope that type is added to the list.
https://redd.it/1hxdv17
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The Old New Thing - Inside STL: Waiting for a std::atomic<std::shared_ptr<T>> to change, part 1
https://devblogs.microsoft.com/oldnewthing/20250108-00/?p=110732
https://redd.it/1hx6xox
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C++ Keywords Knowledge
Hello Everyone i have question do keywords had a specific data type that accept it like string or int or float i new on cpp so what do you think guys ??
https://redd.it/1hwxrf2
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function pointer to member
what is the name and reference for this construct/idiom?
I know it's somewhere in invocable standard but struggling to find exact text.
#include <functional>
struct F {
void g();
void h() {
std::function<void(F&)> g = { &F::g };
g(*this);
}
};
A little library for type-erasure: Erased
https://github.com/qnope/Erased
https://redd.it/1hwqi7a
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children discuss constexpr in C++
https://youtu.be/pSptWKdOHYc
https://redd.it/1hwmpfv
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"break label;" and "continue label;" in C++
Hi, you may have hard that C2y now has named loops i.e. break/continue with labels (https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3355.htm). Following this, Erich Keane published N3377 (https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3377.pdf), which proposes a different syntax.
I am about to publish a C++ proposal (latest draft at https://eisenwave.github.io/cpp-proposals/break-continue-label.html) which doubles down on the N3355 syntax and brings break label and continue label to C++, like:
outer: for (auto x : xs) {
for (auto y : ys) {
if (/ ... /) {
continue outer; // OK, continue applies to outer for loop
break outer; // OK, break applies to outer for loop
}
}
}
There's also going to be a WG14 counterpart to this.
https://redd.it/1hwdskt
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A concept for isspecializationof
Back in the day Walter Brown wrote a paper, wg21.link/p2098, proposing is_specialization_of which could test is a type was a specialization of a template, for example if std::vector<int> is a specialization of std::vector.
I recently tried to make a concept for the same thing. Casey Carter posted on stackoverflow.com/questions/70130735 that the MS standard library had done this in `is-derived-from-view-interface` by doing
template <template <class...> class Template, class... Args>
void derivedfromspecializationimpl(const Template<Args...>&);
template <class T, template <class...> class Template>
concept derivedfromspecializationof = requires(const T& t) {
derivedfromspecializationimpl<Template>(t);
};
See [https://godbolt.org/z/6Pjvxesd1](https://godbolt.org/z/6Pjvxesd1)
I then wondered if you could avoid the extra helper function derived\from_specialization_impl. So I ended up with this
template <class T, template <typename...> class Template>
concept isspecializationof = requires ( T const& t )
{
// Check an immediately invoked lambda can compile
<typename... Args> ( Template<Args...> const& ) { return true; } ( t );
};
which can be made terser although maybe less readabletemplate <typename T, template <typename...> typename U>concept is_specialization_of = std::invocable<decltype([]<typename... Args>( U<Args...> const& ) { }),T>;See `https://godbolt.org/z/KaYPWf9he`
So I'm not a concept or template expert so I was wondering if this is a good way to do this or if there are better alternatives. For example the above does not handle NTTPs and what about partial specializations?
Any thought welcomed
https://redd.it/1hw6a29
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What to do now
Hello everyone , I'm a bachelors student who just got done with DSA course in c++. Other then that I have also learned OOP in c++. Now I know I'm probably no way near a c++ developer but i was wondering what more skills should I acquire to start my journey as a freelancer. Thank you guys in advance
https://redd.it/1hw1ui7
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Latest News From Upcoming C++ Conferences (2025-01-07)
This Reddit post will now be a roundup of any new news from upcoming conferences with then the full list now being available at https://programmingarchive.com/upcoming-conference-news/
C++Online - 25th - 28th February 2025
Registration Now Open \- Purchase online main conference tickets from £99 (£20 for students) and online workshops for £349 (£90 for students) at https://cpponline.uk/registration/
FREE registrations to anyone who attended C++ on Sea 2024 and anyone who registered for a C++Now ticket AFTER February 27th 2024.
Accepted Sessions Announced \- have now also announced the majority of the sessions and workshops that will be presenting at C++Online 2025. You can find the current list at https://cpponline.uk/schedule
Open Calls \- The following calls are now open which all give you FREE access to C++Online:
Online Volunteers \- Attend C++Online 2025 by becoming an online volunteer! Find out more including how to apply at https://cpponline.uk/call-for-volunteers/
Online Posters \- Present an online poster in their virtual venue. Find out more and apply at [https://cpponline.uk/posters](https://cpponline.uk/posters)
Open Content \- Present a talk, demo or workshop as open content at the start or end of each day of the event. Find out more and apply at https://cpponline.uk/call-for-open-content/
Meetups \- If you run a meetup, then host one of your meetups at C++Online which also includes discounted entry for other members of your meetup. Find out more and apply at [https://cpponline.uk/call-for-meetups/](https://cpponline.uk/call-for-meetups/)
C++Now
C++Now 2025 Announced \- have announced that the 2025 conference will run from April 28th - May 2nd. Find out more including what to expect at [https://cppnow.org/announcements/2024/12/announcing-cppnow-2025/](https://cppnow.org/announcements/2024/12/announcing-cppnow-2025/)
CppNorth
CppNorth 2025 Call For Speakers Open \- Speakers have until 23rd February to submit proposals for the CppNorth 2025 conference.
CppCon
CppCon Academy Proposal Deadline \- A quick reminder that any proposals for CppCon Academy 2025 Classes need to be submitted by January 31st. Find out more about submitting here [https://cppcon.org/cfp-for-2025-classes/](https://cppcon.org/cfp-for-2025-classes/)
ADC
ADC 2025 Dates & Location Announced! \- ADC 2025 will return both online and in-person in Bristol UK from Monday November 10th - Wednesday November 12th
Last Chance To Purchase ADCxIndia Tickets \- In-person tickets can be purchased at https://www.townscript.com/e/adcxindia25
https://redd.it/1hvuv0o
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How are you personally binding your library to other languages?
I'm curious how people are writing language bindings for their C++ libraries in practice.
Seems like there's a few possibilities:
1. Use language-specific tools which translate from C++ to idiomatic code in the target language.
e.g. pybind11, cxxrust
2. Write a C API wrapper for your library, then manually write or generate ffi code to call it in the target language. Wrap bindings in some more idiomatic code manually (or leave it to your users).
e.g. cpython, P/Invoke, cgo, rust's extern "C"
generators like SWIG, rust-bindgen can assist with specific languages
3. Use an IDL which generates implementation stubs which you fill out, as well as idiomatic target code.
The only project I've seen attempt this is for real is AutomaticComponentToolkit, which appears to have been created solely for Lib3MF and no one else uses it. It looks neat, though, aside from the lack of commits/stars and rust support.
What is your team doing? What languages do you target? What's the maintenance burden like? Any code or build scripts to share?
https://redd.it/1hvtyoe
@r_cpp
Using C++ as a Scripting Language, part 14
https://fwsgonzo.medium.com/using-c-as-a-scripting-language-part-14-a2cb380b1998
https://redd.it/1hvna7p
@r_cpp
Where to start getting reacquainted with CPP?
I enjoyed my introduction to C++ programming in college but never used it again after that. That was nearly 25 years ago in the Borland days. I'd like to start learning it again just for the heck of it.
Where would be a good place to start? Any recommendations for compilers? IDEs? Preferably something cheap or free. I don't have any particular needs. Just looking for something to futz around with.
https://redd.it/1hvkvv4
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