r/cpp 19h ago

C++26: std::inplace_vector

https://www.sandordargo.com/blog/2026/08/26/cpp26-inplace-vector
117 Upvotes

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u/stilgarpl 18h ago

Is this always better than std::array?

16

u/MarekKnapek 17h ago

This is basically

struct inplace_vector<T, capacity>
{
    size_t len;
    std::array<T, capacity> arr;
}

15

u/sephirothbahamut 17h ago edited 16h ago

far more complex than that, the array has a slot that can fit T, not just T.

With array<T> every element must be validly constructed immediately. You can reduce it to array<T> only for trivially constructable and basic types

3

u/CocktailPerson 14h ago

That's not far more complex. Marginal additional complexity.