C++ - Reddit

Finding a C++ explaining video series I remember seeing a series of youtube videos, where the guy read trough his project code explaining it. The project was some sort of IDE written in c++. I think the videos were recorded live where viewers could ask questions. He also had some script, that he used at the start of the video to pick a source/header file he will be reading and explaining. I have searched for hours, who could I be thinking about? https://redd.it/1lxdvca @r_cpp

gdb and printing an element of my std::map that have a std::pair as a key Hey, I am trying to debug some part of my code. I want to know what's on a specific element of my std::map (lets called it m) container. The key is an std::pair<int,int>. I tried p m[std::make_pair(1,2)]but it says that no symbol "make_pair" in namespace "std" . The code run with no issues, it's just a debugging issue. I also tried some suggestions from our friend gpt but nothing worked. my goal is to make it work inside of gdb. I would love to hear your ideas. EDIT: made the post look more proper, and informed that the code runs with no issues. https://redd.it/1lx5z15 @r_cpp

GCC implemented P3068 "constexpr exception throwing" https://compiler-explorer.com/z/8f769vrz7 https://redd.it/1lx5p0l @r_cpp

libc++ now detects invalid use of std::prev As you may know std::prev is broken in a way that innocent looking code compiles and gives runtime UB. I wanted to check if this has been fixed recently and some good news. It looks like libc++ shipping with clang 20.1 has static_assert that prevents the code from compiling. gcc trunk(libstdc++) still compiles this code and dies at runtime. https://godbolt.org/z/rrYbeKEhP Example of code that used to compile and exhibits runtime UB: namespace sv = std::views; int main() { std::vector<int> v{0,1,2,3,4,5}; auto t = sv::transform(v, (int i){ return i i; }); for (int x : t) std::cout << x << ' '; std::cout << std::prev(std::end(t)); } I do not know all the way in which std::prev can be used wrongly, so I do not claim all uses are detected. And I wish std::prev just worked™ so developers do not need to remember to use std::ranges::prev. https://redd.it/1lx4phn @r_cpp

Looking to create a community of dedicated learners... Hello, im yordan and im looking to form a group of dedicated c++ learners preferably with a c background... the idea: we all use the same resources and discuss them in vc/text channels we show off our projects and do code review so we all learn we work on projects together if interested leave a comment with some info and a discord username https://redd.it/1lwqfk9 @r_cpp

Overloading operators new and delete with C++20 modules I ran into a strange bug with which I need your help. I am writing a kernel in C++20 using modules and in order to be able to fully use classes I need the operator new. Now I can overload it but it fails as soon as I declare the source file as a module (export module xyz;). The errors are as follows: src/mm/new_delete.cc:6:1: error: declaring ‘void* operator new(long unsigned int)’ in module ‘mm.new_delete’ conflicts with builtin in global module 6 | operator new( unsigned long size ) { | ^~~~~~~~ src/mm/new_delete.cc: In function ‘void* operator new(long unsigned int)’: src/mm/new_delete.cc:7:12: warning: ‘operator new’ must not return NULL unless it is declared ‘throw()’ (or ‘-fcheck-new’ is in effect) 7 | return nullptr; // mem::kmalloc( size ); | ^~~~~~~ src/mm/new_delete.cc: At global scope: src/mm/new_delete.cc:11:1: error: declaring ‘void operator delete(void*)’ in module ‘mm.new_delete’ conflicts with builtin in global module 11 | operator delete( void *ptr ) { | ^~~~~~~~ make: *** [Makefile:38: objects/mm/new_delete.o] Error 1 If I remove the export module statement then it compiles but of course can't I call my malloc() routine since it resides in a module. I tried to google but couldn't find anything, seems like c++20 modules are still not widely used. I already use all the compiler flags like nostdinc. Any help is greatly appreciated! https://redd.it/1lwqh0e @r_cpp

learning Cpp from python Hi everyone, I need advice on resources and how to learn cpp. I have always coded with python and am pretty good at it, but now for an internship they asked me to learn cpp and start coding in cpp. I have a little more than a month to learn cpp. Does anyone have any suggestions on where and how to start? I appreciate any help! https://redd.it/1lwl9mz @r_cpp

Developing in Windows environment for Linux in corporate Hi, I joined a company some time ago that developed only for Windows, and now does some backend stuff on Linux. They work with Linux projects in Visual Studio 22 and the developer experience is quite annoying. Lot's of subtle build errors, missing features and configurability that can be easily done with a regular makefile or cmake. I know that VS offers support for cross platform cmake but their implementation is lacking, it doesn't integrate well with our solution based build and some of their ports of the tools like rsync that they use under the hood are also buggy. How your company does it? As someone who is used to develop for Linux in Linux, I find working like this really frustrating. https://redd.it/1lwgh2l @r_cpp

Getting Down in the Bits with Boost.Multiprecision https://www.youtube.com/watch?v=mK4WjpvLj4c https://redd.it/1lwfv9f @r_cpp

kawa::ecs — C++20 Entity-Component System (ECS) — Looking for Feedback & Testers! I’ve been working on a lightweight, header-only ECS called kawa::ecs that’s designed to be blazingly fast, minimal, and easy to use with modern C++20 features. If you’re building games, simulations, or AI systems and want a simple yet powerful ECS backbone, this might be worth checking out! github repo Quick example: #include "registry.h" #include <string> using namespace kawa::ecs; struct Position { float x, y; }; struct Velocity { float x, y; }; struct Name { std::string name; }; int main() { registry reg(512); entityid e = reg.entity(); reg.emplace<Position>(e, 0.f, 0.f); reg.emplace<Velocity>(e, 1.f, 2.f); reg.emplace<Name>(e, "Bar"); // Simple query reg.query ( [](Position& p, Name* n) { std::cout << (n ? n->name : "unnamed") << " is at " << p.x << " " << p.y; } ); float deltatime = 0.16; // Parallel query (multi-threaded) reg.querypar ( [](float dt, Position& p, Velocity& v) { p.x += v.x * dt; p.y += v.y * dt; } , deltatime ); } Thanks a lot for checking it out! I’m excited to hear what you think and help make kawa::ecs even better. https://redd.it/1lweaa3 @r_cpp

C++26: std::format improvement (Part 1) https://www.sandordargo.com/blog/2025/07/09/cpp26-format-part-1 https://redd.it/1lw4ndi @r_cpp

The messy reality of SIMD (vector) functions - Johnny's Software Lab https://johnnysswlab.com/the-messy-reality-of-simd-vector-functions https://redd.it/1lw4zp3 @r_cpp

When I install an unhandled structured exception filter, why doesn't std::terminate get called? https://devblogs.microsoft.com/oldnewthing/20250709-00/?p=111360 https://redd.it/1lw4mg0 @r_cpp

Why is compile-time programming in C++ so stupid? Can I vent here about how much compile time programming in C++ infuriates me? The design of this boggles my mind. I don't think you can defend this without coming across as a committee apologist. Take this for example: consteval auto foo(auto p) { constexpr auto v = p; //error: ‘p’ is not a constant expression return p; } int main() { constexpr auto n = 42; constexpr auto r = foo(n); } This code fails to compile, because (for some reason) function parameters are never treated as constant expressions. Even though they belong to a consteval function which can only ever be called at compile time with constant expressions for the parameters. Now take this for example: consteval auto foo(auto p) { constexpr auto v = p(); //compiles just fine return p; } int main() { constexpr auto n = 42; constexpr auto r = foo(&{ return n; }); } Well. La-di-da. Even though parameter p is not itself considered a constant expression, the compiler will allow it to beget a constant expression through invocation of operator() because the compiler knows darn well that the parameter came from a constant expression even though it refuses to directly treat it as such. ಠ_ಠ https://redd.it/1lw4jej @r_cpp

Can I put module declarations in header files? Issue: https://github.com/Cvelth/vkfw/issues/19 So a while ago, I added module support to the vkfw library. It works fine for my usage with Clang, but recently (not really, it's been a while) GCC 15 released with module support finally stabilized. However, the way that module support is implemented is that in the header file vkfw.hpp, there is something like: // ... #ifdef VKFWMODULEIMPLEMENTATION export module vkfw; #endif // ... so that the vkfw.cpp file can be just: module; #define VKFWMODULEIMPLEMENTATION #include <vkfw/vkfw.hpp> However, GCC 15+ rejects compilation with In file included from .../vkfw-src/include/vkfw/vkfw.cppm:3: .../vkfw-src/include/vkfw/vkfw.hpp:219:8: error: module control-line cannot be in included file However, I can't find anywhere in the spec/cppreference that disallow this. So is this allowed at all, or it's just a GCC limitation? https://redd.it/1lw2g0d @r_cpp

Polymorphism Without virtual in C++: Concepts, Traits, and Ref https://medium.com/@eeiaao/polymorphism-without-virtual-in-c-concepts-traits-and-ref-ce9469a63130 https://redd.it/1lvnfuf @r_cpp

Roll your own in-game UI with Clay and NanoVG https://dev.to/linkdd/roll-your-own-in-game-ui-with-clay-and-nanovg-part-2-25pf https://redd.it/1lvmk7a @r_cpp

C++ with no classes? https://pvs-studio.com/en/blog/posts/cpp/1259/ https://redd.it/1lvdvsd @r_cpp

Looking for a C++ ECS Game Engine Similar to Bevy in Rust Hi everyone, I'm a C++ developer diving into game development, and I'm really impressed by the Entity-Component-System (ECS) architecture of Bevy in Rust. I love how Bevy handles data-driven design, its performance, and its clean API for building games. However, my current project requires me to stick with C++. Does anyone know of a C++ game engine or library that offers a similar ECS experience to Bevy? Ideally, I'm looking for something with: A modern, clean ECS implementation Good performance for real-time applications Active community or decent documentation Preferably lightweight and modular, without too much bloat I've come across engines like EnTT, which seems promising, but I'd love to hear your recommendations or experiences with other C++ ECS libraries or engines. Any suggestions or comparisons to Bevy would be super helpful! Thanks in advance! https://redd.it/1lved2o @r_cpp

Henrik Fransson: C++ On Time https://youtu.be/aKyj5ZycnsU https://redd.it/1lve9od @r_cpp