Even better, starting with C++26, and considered to be done with DR for previous versions, hardned runtimes now have a portable way to be configured across compilers, instead of each having their own approach.

However, you still need something like -fbounds-safety in C++, due to the copy-paste compatibility with C, and too many people writing Orthodox C++, C with Classes, Better C, kind of code, that we cannot get rid of.

I'm sure std::span is great, but I like mine better :)

I find it a bit hard to justify using the STL when a single <unordered_map> include costs 250ms compile time per compile unit.

The fact that I don't have to step through this in the debugger is also a bonus:

  template <size_t _Offset, size_t _Count = dynamic_extent>
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto subspan() const noexcept
      -> span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset> {
    static_assert(_Offset <= _Extent, "span<T, N>::subspan<Offset, Count>(): Offset out of range");
    static_assert(_Count == dynamic_extent || _Count <= _Extent - _Offset,
                  "span<T, N>::subspan<Offset, Count>(): Offset + Count out of range");

    using _ReturnType = span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset>;
    return _ReturnType{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count};
  }

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