Question

When using the in storage class in D the data is immutable to your function. Does this also pass in the data by reference and not by value? I noticed that in ref is not valid.

If in doesn’t pass in the data by reference, is there a way to get the data by reference but have a guarantee to the caller that the data will not be modified?

Answer 1

in parameters are not passed by reference.

As far as I can tell from the documentation, in is just a shortcut for const scope. I do not see any way to emulate ref in parameters, since ref scope is illegal. As BCS said, you can use ref const if you don’t care about the scope storage class.