Re: [libgpiod][PATCH v2 3/3] bindings: cxx: implement C++ bindings for libgpiod v2.0

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Fri, Jul 16, 2021 at 9:44 AM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
>
> On Fri, Jul 16, 2021 at 12:18 AM Ben Hutchings
> <ben.hutchings@xxxxxxxxxxxxx> wrote:
> >
> > On Thu, Jul 15, 2021 at 10:10:01PM +0200, Bartosz Golaszewski wrote:
> > > This is the bulk of work implementing C++ bindings for the new libgpiod
> > > API. The tests are not converted yet but the examples are fully
> > > functional. More details in the cover letter as this patch will be
> > > squashed with the one for the core C library anyway.
> > [...]
> > > +class line_config
> > > +{
> > > +public:
> > > +
> > > +     /**
> > > +      * @brief Direction settings.
> > > +      */
> > > +     enum : int {
> > > +             DIRECTION_AS_IS = 1,
> > > +             /**< Request the line(s), but don't change current direction. */
> > > +             DIRECTION_INPUT,
> > > +             /**< Request the line(s) for reading the GPIO line state. */
> > > +             DIRECTION_OUTPUT
> > > +             /**< Request the line(s) for setting the GPIO line state. */
> > > +     };
> > [...]
> > > +class line_info
> > > +{
> > > +public:
> > > +
> > > +     /**
> > > +      * @brief Direction settings.
> > > +      */
> > > +     enum : int {
> > > +             DIRECTION_INPUT = 1,
> > > +             /**< Direction is input - we're reading the state of a GPIO line. */
> > > +             DIRECTION_OUTPUT
> > > +             /**< Direction is output - we're driving the GPIO line. */
> > > +     };
> > [...]
> >
> > Could these be enum class types, or does that introduce an ABI issue
> > if you extend them later?
> >
> > Ben.
>
> I'm not sure there would be any benefit to enum classes here except
> for longer scope when using them in code. I would prefer to leave it
> this way.
>
> Bartosz

Actually after a second thought, it wouldn't make it long - it would
just look like: line_info::direction::INPUT instead. Maybe it is a
more C++ approach after all.

Bart