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points by gmueckl 4 days ago | 0 comments

The feature parity question goes both ways: rust won't ever be able to express some things that are possible in C++.

Like?

Algorithms that safely mutate the same data structure on multiple threads and do so safely because of some complex algorithmic properties that guarantee that the changes do not overlap?

[–] afdbcreid 4 days ago

Rust can do that just fine. https://doc.rust-lang.org/stable/std/cell/struct.UnsafeCell..... "some complex algorithmic properties that guarantee that the changes do not overlap" are exactly the place to use unsafe and encapsulate it.

If you mean things that formally create a data race, then C++ cannot do that either.

[–] tcfhgj 4 days ago

Why can Rust not do that?

[–] gmueckl 4 days ago

How do you create shared mutable ownership of overlapping ranges of a single flat array in rust?

[–] tcfhgj 4 days ago

similarly except the algorithm to Mutex<[T]> and Arc?

[–] gmueckl 4 days ago

How does this work e.g. for an array of integers that several workers threads write to at random, non-overlapping positions?

[–] tcfhgj 3 days ago

1. by implementing your complex algorithm? 2. if they don't overlap, they can't be random, can they?

Rust can literally do anything programmatically. Idk why you think it cannot do something.