You appear to be using "generic" to mean "C-ish". That is not what the word means, in context, and there is no reason to do any of it anyway. "Proofing the code"? Does that mean anything at all?

For RAII on heap objects, you have std::unique_ptr, and no boilerplate. Anyone failing to lean into RAII to manage resources is just choosing to write unreliable code. Or C, but I repeat myself.

Due to language limitations, a lot of C programmers make all their variables shared pointers, which means they don't have to figure out how to do value semantics, moving and copying objects, especially in multithreaded environments.

Interestingly, it seems Rust programmers do the same too, because otherwise programming in Rust is too hard.

> Due to language limitations, a lot of C programmers make all their variables shared pointers, which means they don't have to figure out how to do value semantics,

I wouldn't approve. Make shared (i.e. ref-counted) pointers when actually needed. Writing C is best when not mimicking bigger languages (i.e. with GC), but when figuring out how a system can work optimally.

You might not approve, but the reality is that most C code is built like that.

I assume you mean C++ here?

In any case, in my experience this bad practice comes from Java devs who’ve moved to C++.

Java Disease is its own topic.

But most shared pointer ownership in C is wholly ad hoc, without even reference counting.

No, I mean C. People don't do that in C++, since C++ provides ways to define value semantics (copy, move, assignment).

Your theory is that Rust programmers "make all their variables shared pointers" ?

Even if I generously assume you're thinking of C++ "shared pointers", and so you've concluded that Rust's Rc<T> (a reference counted T) is basically the same thing, I don't see where you'd come to the conclusion that Rust programmers do this for "all their variables" as this seems wildly unlikely.

Just look at the code in cargo. (A)rc is all over the place.

It's essentially a cop out to not have to think about ownership and lifetime, and not have to worry about the borrow checker.

The fact that this is so pervasive throughout Rust code is for me a sign that Rust failed to deliver on its initial promise. The borrow checker was meant to be its main value added. But heh, people still find value added to Rust otherwise.

Hmm. So the code I happened to have open was Aria's "Cargo mommy" which has neither Arc nor Rc anywhere, but is only a toy.

So I did go look at Cargo itself, but unlike you although I do see some use of Rc and fewer of Arc it was scarcely "all over the place" when I looked and in the cases I spent any time actually thinking about it's a shared value, so, yeah, that makes sense.

I randomly looked at cargo/core/profiles.rs and cargo/core/registry.rs and cargo/core/compiler/compilation.rs without finding either Rc or Arc used in those files at all. Searching across the whole repository I found some places which do use Rc, and fewer using Arc (implying this data is shared between threads) -- but this doesn't really support your original claim does it?

I never meant cargo itself.

> It's essentially a cop out to not have to think about ownership and lifetime

Not a cop out. Something very much like Rc<> is needed whenever an object's lifecycle might be independently extended by multiple referencing "owners", none of which is subsumed by the others. That's a matter of broad high-level design that can't generally be avoided, least of all in a multi-threaded context (as shown by the use of Arc<>).

> "Proofing the code"? Does that mean anything at all?

Since you're already schooling me on the meaning of terms, you probably have enough experience to have realized that the typical code begins life in a stubbed out form that is barely functional enough to deliver first results. It is then iteratively enhanced and made more widely applicable, more robust, more refined, better specified, more performant, and so on. In the process, the code is undergoing many revisions, and moving data structures from automatic storage (stack) to the heap is very typical.

Another word I'm thinking of for this process is "consolidation", which I have also used. My apologies if I don't speak in your terms / in the most precise terms.

I don't have experience of this "moving from ... stack to the heap", in C++. Correct code is the same wherever the objects live, whether stack, member, or heap. Changing it costs time and adds faults.

This proofing process is another example of what makes coding C more costly and buggy than coding C++. I did it for years, and miss it not at all.

If writing systems-level code solving for non-trivial requirements, the majority of the state has a lifetime that outlives any particular function call. That's when you need to move that state to the heap.

There's no clear scope anymore, ownership has to be moved from function scopes to RAII managed container structures. Things are quickly getting more complicated and expensive (software complexity/bloat, compile times, binary size...) when you have to nest your structures in templated containers that don't know what you're nesting in them...

This is where all the complexity with 17 constructor types and 99 move semantics with const, non-const, r-valued references and abstract virtual base classes came from, and there might be less than a dozen persons left on the planet who really understand it all...

With RAII, it is trivial to move things from stack to heap, or to a member of something that might be on the stack or heap or in a container, without changing any of the code that implements the object. Most usually you don't need to declare or define any constructors, assignment operators, or a destructor; the compiler provides them, and guarantees they are correct. (Sometimes you provide one constructor as a convenience for users.)

It has been many years since I found a use for an abstract virtual base class.

Literally millions of people understand it all, and use it every day with no difficulty. You don't need to invent difficulties, or waste days "proofing" code that may be written exactly once and never touched again.

To clarify, I think by “move things from stack to heap” you mean “move values from stack to heap”, where, e.g., `std::vector<int>` is a value. The vector’s data is still on the heap (or in the allocator’s pool for `std::pmr::vector<int>`) but the value in the sense of value-semantics is moved from stack to heap.

I guess what they mean is moving to static memory allocation, not to the heap. That is something done rather frequently when proofing embedded C code, because it's simply to easy to mess up manual memory management. Only reason to move from stack to heap would be for huge data structures not give stackoverflow, something that can be hard to test for.

"It's quite easy to close the things that you need to close"

Very true. It is easy. Not difficult. That doesn't seem to stop enormous amounts of C++ code being created in which this is simply got wrong. Just because it's easy doesn't mean that huge numbers of programmers won't still get it wrong. They do. Regularly. If they adopt RAII conventions, they screw it up far less frequently. Those are the facts.

I prefer reducing complexity instead of hiding it in language cleverness. (Because hiding complexity doesn't make it go away). Try adopting ZII (Zero is initialization) and context managers (pooling, chunking, freeing in batches etc.), this can reduce the amount of boilerplate to a minimum. Writing generic code like that (down to the binary level) also helps improving many other metrics like executable size etc.

That's nice, and I'm sure your code is just lovely, but there's just one of you and millions of people writing C++ who can't do that but can just about manage some simple RAII.

> Because hiding complexity doesn't make it go away). Try adopting [..] context managers (pooling, chunking, freeing in batches etc.), this can reduce the amount of boilerplate to a minimum

"don't hide complexity in small, single-purpose, composable containers, instead hide complexity in hulking behemoths which can consume months of refactorings & iterations" ?

That's not simplifying your code to be generic. That's adopting a particular framework & coding style. Which yes, you have to do in C, but you're doing that because of language issues. You're not saving yourself from "language cleverness"