On Wed, Feb 12, 2025 at 2:13 PM Kevin Wolf <kw...@redhat.com> wrote:
> Yes, we definitely need some proper bindings there. I'm already tired of
> writing things like this:
>
> return -(bindings::EINVAL as std::os::raw::c_int)
>
> Or even:
>
> return e
> .raw_os_error()
> .unwrap_or(-(bindings::EIO as std::os::raw::c_int))
This by the way seemed incorrect to me as it should be
return -(e
.raw_os_error()
.unwrap_or(bindings::EIO as std::os::raw::c_int))
(leaving aside that raw_os_error does not work on Windows)... But then
I noticed that read_raw() also does not negate, which causes the error
to print incorrectly...
> Which actually already shows that your errno binding patch does the
> opposite direction of what I needed in this series.
... so my patch already helps a bit: you can still change
if ret < 0 {
Err(Error::from_raw_os_error(ret))
} else {
Ok(())
}
to
errno::into_io_result(ret)?;
Ok(())
and avoid the positive/negative confusion.
Anyhow, I guess the first one wouldn't be much better:
return errno::into_negative_errno(ErrorKind::InvalidInput);
whereas the second could be
return errno::into_negative_errno(e);
But then the first is already a special case; it only happens where
your bindings are not trivial thanks to the introduction of the
Mapping type.
Paolo
> My problem is when I
> need to return an int to C, and I either have an io::Result or I just
> want to directly return an errno value. So we'll have to add that part
> to your errno module, too.
