Re: [libc-coord] Re: [musl] Re: regression in man pages for interfaces using loff_t

Szabolcs Nagy
2023-07-01T13:42:43Z

* Paul Eggert <eggert@cs.ucla.edu> [2023-07-01 00:24:27 -0700]:
> On 2023-06-30 16:37, Rich Felker wrote:
> > This is still changing the documentated signature, which isn't really
> > nice, and would not be compatible with glibc unless glibc went out of
> > its way to hide those functions when _FILE_OFFSET_BITS is 32.
>
> I don't see any incompatibility with glibc and the changes I proposed. The
> changes merely weaken the spec in the man pages in an area where the spec
> should be weakened. glibc is compatible with the spec before it was changed
> to use off64_t, it's compatible with the spec now that it uses off64_t, and
> it would continue to be compatible with the spec if the proposed changes are
> adopted.

loff_t * can be incompatible with off64_t * as well as off_t *.

the documentation change can break the api of an implementation,
it is not weakening the spec.

(it can also break abi if loff_t has different abi than off64_t. two
integer types can have same range, representation and syscall argument
passing abi, but different libc abi and different c++ abi)

i don't think you can claim that glibc is compatible either way, as
a future target port can define loff_t differently than off64_t.