Comment by kanbankaren | Hacker News Reader

Comment by kanbankaren | Hacker News Reader

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> But I can’t understand why a language’s choice to impose complex rules like C++ move constructor hell is an inevitable outcome of irreducible complexity in systems programming.

Programmer here for 30 years in C/C++. It is true that C++ has become a more complex language after rvalue references were introduced, but you have to understand the rationale behind C++: a language suitable for large scale systems programming with *ZERO OVERHEAD*.

The language complexity especially rvalue references was to reduce overhead. Pre-C++-11, there were many code patterns that involved constructing temporaries and destroying them immediately.

C is not suitable as a large scale programming language. Just look at the number of defects in the Linux kernel and their attempt at extending the language through custom compiler attributes to overcome the limitations of C.

> but you have to understand the rationale behind C++: a language suitable for large scale systems programming with ZERO OVERHEAD.

Is this the reason why C++ was created, or the last remaining niche that C++ is holding onto?

I remember the early 90's, and it very much seemed like C++ was being pushed as both a general-purpose language and the logical successor to C, insert Linus Torvalds rant here. On top of that, C++ made the decision to privilege a form of polymorphism that had pointer-chasing baked into its internal design, as well as having a good chunk of the standard library being considered a footgun best to avoid due to how much it blew up compile-times.

I think that C++ is a zero-overhead language now because a series of general purpose languages that came afterwards took the other niches away from it, plus the benefit of 30+ years worth of compiler optimizations that were originally largely aimed at the mountain of C code that was out there.

EDIT: Almost forgot about exceptions, the other enormous performance footgun that was an early pre-standard C++ feature.

C++ doesn't have zero overhead, though. The committee is unwilling to take ABI breaks and so have left performance on the table. For instance, unique_ptr<T> can't be passed in registers but T* can.

Zero overhead is a fiction the committee likes to tell themselves, but it's not true.

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