Re: [libgpiod v2][PATCH] misc: make gpiod_is_gpiochip_device() not set errno

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Fri, Jul 1, 2022 at 1:43 PM Kent Gibson <warthog618@xxxxxxxxx> wrote:
>
> On Fri, Jul 01, 2022 at 01:00:56PM +0200, Bartosz Golaszewski wrote:
> > This function should just report whether the file indicated by path is
> > a GPIO chip or not. Let's rework it to not set errno. Failure to open a
> > chip should still report errro numbers like before.
> >
>
> This is will break my tool patch, for sure.
> My gpiodetect uses the errno behaviour to give a clue as to why a chip
> might not be available to a user, and that work was already done in
> gpiod_is_gpiochip_device().
> There might be other places the errno was propagated as well, but
> whatever, I'll sort something out.
>

Doesn't it make more sense to call gpiod_is_gpiochip_device() and then
if it returns true, just try to open it and then report failure?

Bart