Re: [libgpiod][PATCH 04/16] treewide: unify gpiod_line_config/request_get_offsets() functions

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Tue, Jan 17, 2023 at 6:44 AM Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
>
> On 16-01-23, 22:39, Bartosz Golaszewski wrote:
> > On Mon, Jan 16, 2023 at 6:52 AM Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> > > > +        let mut offsets = vec![0; num_lines as usize];
> > > > +
> > > > +        // SAFETY: gpiod_line_config is guaranteed to be valid here.
> > > > +        unsafe { gpiod::gpiod_line_config_get_configured_offsets(self.config,
> > > > +                                                                 offsets.as_mut_ptr(),
> > > > +                                                                 num_lines) };
> > >
> > > Can the returned value be < num_lines here ?
> > >
> >
> > Ah, of course it can. Need to add a test case for that. How do I set
> > the size of offsets to whatever this function returns?
>
> Instead of any heavy operation, you can rather do something like this:
>
> let num = unsafe { gpiod::gpiod_line_config_get_configured_offsets(self.config,
>                                         offsets.as_mut_ptr(), num_lines) };
> for offset in offsets[0..num] {
>         ...
> }
>

It sees 'offset' becomes an instance of std::ops::Range. Is there
anything more to add here?

Bart