What does ref means

[bearophile]

malio:

> Okay, thanks bearophile. But I currently doesn't exactly understand what's the difference between "ref" and "const ref"/"immutable ref". If "ref" is syntactic
> sugar for pointers only (like your first example), does it also create a copy of the parameters which are marked as "ref"? I thought that pointers (and in
> this context also "ref") avoid the creation of costly copies?!?

"ref" just passes a reference to something, so it doesn't perform copies.

"const ref" or "immutable ref" just means that you can't change the value (with the usual semantic differences between const and immutable, that are both transitive).

For the programmer that reads your code, "ref" means the function you have written will usually modify the given argument, while "const ref" means it will not modify it.

Bye,
bearophile