[apotheon]

> What is your definition of "portable"?

In that particular statement at the beginning of my preceding comment, I meant portability across compiler implementations.

> Eliminating an argument from a function by hiding it in a data structure is not that compelling to me since I can just do that on my own.

I meant to refer more to the idea that, when doing it on your own in a particular way, the compiler could support applying a (set of) constraint(s) to prevent overflows (as an example), such that any constraint couldn't be bypassed except by very obviously intentional means. Just automating the creation of the very, very simply constructed "plus a numeric field" struct seems obviously not worth including as a new feature of the standardized language.

> the fact that length+pointer is such a common construct indicates that most people don't have any issues with it

I think you're measuring the wrong kind of problem. Even C programmers with a high level of expertise may have problems with this approach, because it's when programmer error causes a problem not caught by code review or the compiler via buffer overflows (for instance) that we see a need for more.