Re: [PATCH 1/9] xdiff: use ssize_t for dstart/dend, make them last in xdfile_t

>
> Ezekiel Newren <ezekielnewren@gmail.com> writes:
>
> > In my compat/rust_types.h file (which was dropped) I defined isize
> > using ptrdiff_t rather than ssize_t. Maybe that file should be revived
> > so that we don't have confusion in code reviews when structs are being
> > expressly converted for the purpose of Rust FFI? I'd really like to
> > bring that file back so that everyone has a clear reference for how C
> > types map to Rust, but no one seemed to like it except me. Maybe it
> > should be an adoc file rather than a header?
>
> I may be mistaken, but I thought that the latest agreement was to
> use conceptually the "same" type in each language, have each
> language call that type in its native way, and if needed convert at
> the FFI boundary.  So if we agree to use, for example, 64-bit signed
> integer type for counting things plus returning error conditions via
> negative values, maybe C-side can agree to use i64 for it, without
> having to worry about how that thing is called in Rust side.

> I am not sure in what way <compat/rust_types.h> should be used, and
> perhaps a documentation file may be sufficient as you suggest, but
> in any case, I agree that it should be made clear to everybody what
> C-types are to be mapped to what Rust types and vice versa, and if
> some C-types have no corresponding Rust type in that mapping, or if
> some Rust types have no corresponding C-type, that type needs to be
> converted before they reach the FFI boundary.