[fathyb]

Another reason it is not true: Rust has fat pointers, eg. `std::unique_ptr<const uint8[]>` and `Box<[u8]>` both contain the same allocation data, but `Box` will be 128-bit on 64-bit systems.

[HarHarVeryFunny]

What's the utility of having a 128-bit pointer on a 64-bit system ?

[fathyb]

`Box<[u8]>` stores the pointer and its length (2 x size_t), `std::unique_ptr<const uint8_t[]>` only stores the pointer.

That's for slices, for dynamically sized types (eg. `Box<dyn ToString>`) it contains a pointer to the virtual table.

https://doc.rust-lang.org/nomicon/exotic-sizes.html

[bitcharmer]

Where can I find details like this about Rust?

[fathyb]

The Rustonomicon is a good start, on fat pointers: https://doc.rust-lang.org/nomicon/exotic-sizes.html

> Because they lack a statically known size, these types can only exist behind a pointer. Any pointer to a DST consequently becomes a wide pointer consisting of the pointer and the information that "completes" them (more on this below).