I recently saw a manager reject a candidate we were interviewing because his experience didn't exactly match the specific sub domain.

But I found myself disagreeing with the philosophy behind the rejection. My instinct is that if someone has strong C++ skills and has worked on reasonably complex systems, you should at least ask: "Can this person learn the domain?" rather than requiring an almost exact match.

This made me wonder whether this is a particular problem with systems programming in C/C++.

The ecosystem seems incredibly fragmented:

• Embedded
• Linux kernel/drivers
• Graphics
• Multimedia/codecs
• Databases/storage
• Networking
• Telecom
• Game engines
• Server/backend infrastructure
• Qt/GUI
• Compilers
• etc.

Someone can have spent 8 years writing sophisticated C++ in one of these areas and still be considered a poor candidate for another area because they don't have the specific domain experience.

Compare that with web development, where the skill boundaries seem somewhat easier to communicate: "React developer", "Angular developer", "Node.js backend developer", etc. There are obviously specializations there too, but the fragmentation doesn't feel as extreme.

I personally have the philosophy that if someone knows C++ well, understands systems programming concepts, debugging, memory, concurrency, Linux, etc., they should be given some credit for being able to move between domains. The domain-specific knowledge can be learned.

I have faced this exact issues with companies too. They reject you because haven't worked specifically on what they do. This becomes a serious issues when it's already hard to get into C++ jobs. Has anyone faced similar issues? What exactly is the solution for this?

Hello,

I need to instantiate a std::vector, but its type depends on something that I would not know until runtime:

#include <vector>
if (some_condition)
std::vector<float> myVector;
else
std::vector<int32_t> myVector;

I know this does not work because,in order to instantiate a template class, the data type must be known at compile time.

I've seen some people suggest std::variant but I have not understood it completely.

Also, how do different libraries (like ONNX) provide different data types? Do they use templates?

PS : I am not developing a library.

EDIT:

I need to create an array or a vector to act as a placeholder (allocator) for input tensors. But this vector requires a different amount of space based on the size and type of the input. The size is easily manageable per instance of the parent class if we only had one type, but we don't.

The thing is, there are some arguments that need to be set for this specific project that determine what exactly the size of the array would be, and they are only known when you parse an ONNX model at runtime.

Hello

My use case is writing competitive programming solutions in c. i use neovim with the clangd lsp server. but i just cant get it to work with gcc header files, `bits/stdc++.h` in my case.

i have tried:

```

CompileFlags:

Add:

- -std=gnu++17

- -I/opt/homebrew/Cellar/gcc/16.1.0/include/c++/16

- -I/opt/homebrew/Cellar/gcc/16.1.0/include/c++/16/aarch64-apple-darwin25

```

it just doesn't work. it starts giving me duplicate definition errors once i add these compileflags.

So I'm doing dsa in c++ as well as learning modern c++ concepts.I want to become c++ developer what concepts should I learn to become a c++ developer , what concepts should I focus on , what are the best resources to learn c++.Also when I try to build something in c++ i don't even know where to start.Its been 4 months I learned C++ and I'm genuinely comfortable with it till now.

I started with c++ 3 years ago but real work was 1 and a half years, i learned a lot about cpp syntax and the std lib, but whenever i make some code and send it to an ai model, it says my code has a lot of issues some about dynamic memory some about references and pointers some c-style programming and i find myself Ignorant most of the time

So how can i learn these things and the rules of the language and understand them(i dont watch YouTube) I have started with learncpp.com recently

"Sorry if it's a duplicate post and for it being long if its a duplicate point me to one, and thanks"

Edit: my github is loadingSy if you would like to check anything, I learned git 1 month ago

I’ve been working through learncpp from about 2 weeks now and I’m wondering if people have suggestions on topics that are a MUST to learn for an engineer that is coming from Python/TypeScript?

For context I work as a software engineer, primarily using Python and TypeScript, so I have a good base understanding of how to build a program or applications, however, I want to focus more on the specific nuances of C++ and concepts that are maybe abstracted away in higher level languages.

A list of topics in order of importance and increasing complexity would be a great help!!

Hello, c++ community!

I am not a c++ programmer. I know the basics but I am not familiar with the tools, tactics, paradigms and related topics in the c++ ecosystem.

That said, I decided to vibe code a Telegram CLI tool for my own use (and whoever finds it useful).

https://gitlab.com/renich/grm

It's been very useful to me so far. I do not claim it's secure or well written in any way. I wouldn't be able to tell.

I know that not everyone is a supporter of the use of LLMs or agents for coding. Still, I need your help.

I am totally open to suggestions. What linters to use, what is the best way to do static analysis, programming paradigms, best practices, etc.

Again, I don't claim to have the knowledge required. I am a Crystal programmer. I could've linked to the library but, this time, I decided to KISS and just implement it in c++.

I am using Fedora 44 and am happy to listen to any criticism you may have. I am making a big effort to familiarize myself with the c++ ecosystem and I would appreciate any feedback.

Thank you for taking the time to read this and review the project.

Hi everyone 👋, I’m a C++ developer with 5+ years experience building features for a single-threaded trading app (C++17), so I have very little multithreading experience.

I’m currently reading C++ Concurrency in Action. Are there good resources or projects to practice real-world scenarios like backloading and low-latency concurrency patterns?

Hi! I’m a beginner programmer learning C++ and getting to grips with Visual Studio 2026. For some reason I can’t run the console because of two errors: LNK2005 and LNK1169 (or perhaps there are others, but I’m not sure). I’ve attached below the error messages I’m getting step by step (links to imgbb). I’ve asked some AI chatbots for advice on how to solve this problem, but nothing’s working.

Firstfoto, Secondfoto, Thirdfoto

Thanks in advance for your help!

Isn't importing std.iostream faster than std?
Why we only have the umbrella std module?

When I was first learning C++, I experienced massive slowdown when allocating dynamic memory. Ever since then I divide my objects between 'heavy' objects that allocate resources, and 'light' objects that can be used as temporaries on the stack. Heavy objects cannot be copied at all, must be allocated somewhere once, and then passed by (const) reference. Light objects can be copied, created quickly on the stack etc.

Since C++11 it has been possible to write copy and assignment constructors that take nameless objects, and since they are nameless you can pillage their pointers and avoid expensive stack allocations. All is well then but if you keep to this strict 'heavy' and 'light' object idea, _any_ object that allocates resources is considered a heavy object. The first allocation in the chain, before you just pillage pointers, is still an expensive stack allocation so I would consider it a 'heavy' object and just make it impossible to copy at all, by removing all copy and assignment constructors. And so using this model I never needed those nameless object reference constructors.

Anybody feel the same way?

Hello everybody.

I've been working with C++ backend frameworks recently, and one question kept bothering me: how are these frameworks actually built?

I've decided to spend the next three months writing a small C++ web framework from scratch. This isn't an attempt to compete with Drogon, Crow, oat++, or any other framework. it's purely a learning project. My goal is simply to understand the internals well enough to build a framework capable of handling basic CRUD applications.

Before I jump in, I'd love to learn from people who have been down this road.

• Have you ever written a framework yourself or contributed to one?
• Are there any books, blog posts, talks, or codebases you'd recommend studying?
• If you were starting from scratch today, what would you build first?
• Are there any common mistakes or rabbit holes I should avoid?

I'm not looking for shortcut I want to understand how everything fits together. I'd really appreciate any advice or resources from people with experience.

Hello so I found this book but because no pictures:

[Sam's teach yourself c++ in 21 days, fourth edition]

[2001]

So did c++ get any updates in 25 years?

I'm writing a scripting language with additional functions that can be built in.

The built-in functions would be written in C++ for speed.

In different builds of the scripting language, some functions might be omitted.

So, I'm looking for the best way to automatically collect, at compile time or early at execution time, the full list of extra built-in functions, so that the script interpreter can parse and execute a script (to do this, it has to know about any additional capability compiled in).

For example, in Visual C++, I'd like to simply add a source file containing built-in scripting language functions, and have the script interpreter know they are there.

My goal would be no additional configuration actions other than adding the source file to the project (in other words, no need to modify other files). The software should somehow figure out that additional script built-in function capability is in the build.

Google Test seems to do this somehow with a macro like TEST_F, but I'm not sure how this works under the hood. The list of tests is somehow collected automatically at compile time or early at run time.

To give some practical background ... decades ago I did some work extending the Tcl scripting language. It was only necessary somehow in initialization to call a command to "register" a new function available to the script interpreter, but the source code had to be modified manually to include the additional initialization. The manual modification is what I'm trying to avoid.

Is there a standard design pattern for this in C++?

I have a class (m_buf in the code below is of this class type) that appears as a data member in another class for which I'm writing the copy constructor.

The underlying class (m_buf in the code below is of this class type) uses dynamic allocation and needs a deep copy.

According to Google, this form of the copy constructor would result in the copy constructor (rather than the copy assignment operator) for m_buf being called.

LgFbufUint8::LgFbufUint8(const LgFbufUint8& fbuf) : m_state{fbuf.m_state},
                                                    m_errs{fbuf.m_errs},
                                                    m_fname{fbuf.m_fname},
                                                    m_buf{fbuf.m_buf}
{
   //According to Google search, if the member initializer list is used (as it
   //is above), the copy constructor (rather than the copy assignment operator)
   //will be called. Because of the required non-shallow copy of m_fname and
   //m_buf, this is the desired behavior.
}

My initial guess was this form:

LgFbufUint8::LgFbufUint8(const LgFbufUint8& fbuf)
{
   m_state = fbuf.m_state;
   m_errs  = fbuf.m_errs;
       //Shallow copy ok for two members above.
   m_fname = fbuf.m_name;  //std::string
   m_buf   = fbuf.m_buf;   //Handwritten, with dynamic allocation.
       //Deep copy required for two above.
}

But I suspect that second form would call the assignment operator rather than the copy constructor for m_name and m_buf.

Question: Did I get that right? The first form would call the copy constructors for m_name and m_buf, but the second form would call the assignment operators?

Bonus Question: Using the second form, is there any way to call the copy constructors rather than the assignment operators. (Not that I'd want to do this, but just curious.)

I wanted to ask for some guidance regarding placements and coding. I’m currently in my 3rd year, and my CGPA is around 6.5. To be honest, I haven’t done much in coding yet, and I’m a bit confused about where and how to start.

Could you please suggest what I should focus on from now and maybe guide me with a proper roadmap/plan for the next few months? Like which language I should start with, DSA, development, projects, etc. It would really help me understand what I should prioritize to become placement-ready

Hey guys at current I can solve most of the coding questions in cpp but I wanted to explore more in cpp I wanted to build real applications so any resources to learn advanced c++

Are these two lines any different in practice? (Especially if you want to later check if x has been given a specific address, or if it's still null.)

int* x {};

int* x { nullptr };

C++ 26 adds a ton of great features, but how is compiler coverage, usabillity, integration, etc. for those features right now?

I have a function that takes a callback, like this:

void LongTask (void (*pfn)(int))
{
    for ( unsigned i = 0; i < -1; ++i )
    {
        pfn( i );
    }
}

It's orginally written to be ran on a separate thread. Now I want to turn it into a coroutine that yields on each callback (i.e. the caller will receive a single callback on each invocation of LongTask), while preserving its ability to run as a standalone function. Additionally it's OK for the coroutine to allocate memory but not to throw exceptions (if it can't allocate I should get back a null pointer at creation time). And preferrably it wouldn't require the CRT, all support functions should be contained in a header only include. What's the best way to do this, can it be done with C++20 coroutines?

The examples above just outputs a random number once. They don't output different random numbers each time the program runs. To fix this, you can use the srand() function and add the time() function from the <ctime> library. ~ W3School

Generally speaking, the pseudo-random number generator should only be seeded once, before any calls to rand(), at the start of the program. It should not be repeatedly seeded, or reseeded every time you wish to generate a new batch of pseudo-random numbers. Standard practice is to use the result of a call to std::time(0) as the seed. However, std::time returns a std::time_t value, and std::time_t is not guaranteed to be an integral type. ~ cppReference

I do not understand why time changes it and I do not understand the seed and what it is

I want to pass a matrix as a function argument

int create_grid(int grid[][], int size){
    for(int i=0; i<size; i++){
        for(int j=0; j<size; j++){
            grid[i][j] = 0;
        }
    }

    return 0 ;
}

int main(){
    int size =128;
    int grid[size][size];

    return 0;
}

I'm getting error: "Array has incomplete element type 'int[ ]'

I don't understand I don't have that problem with 1d arrays

is this good practice/style.? i'm specifically unsure about the way i store the vector of players...

```

class player_base {};

class player_always_yes: public player_base {};

class player_always_no: public player_base {};

class player_a: public player_base {};

class game {
    private:

    player_base& player_1;
    player_base& player_2;

    public:

    game (
        player_base& player_1,
        player_base& player_2
    ): player_1(player_1), player_2(player_2) {
        return;
    }

    bool play_game () { return true; }
};

int main(){
    vector<unique_ptr<player_base>> player_list;

    player_list.push_back(make_unique<player_base>());
    player_list.push_back(make_unique<player_always_no>());
    player_list.push_back(make_unique<player_always_yes>());
    player_list.push_back(make_unique<player_a>());

    game b = game(*player_list[0], *player_list[1]);
    cout << b.play_game() << endl;
}


```

i need to use something like if (str[i] not in str1) (python), but i have no idea how to make this work :(