Re: [libgpiod][PATCH 2/3] libgpiosim: new library for controlling the gpio-sim module

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Thu, Apr 29, 2021 at 7:00 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> On Thu, Apr 29, 2021 at 03:07:49PM +0200, Bartosz Golaszewski wrote:
> > On Thu, Apr 29, 2021 at 1:23 PM Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > > On Thu, Apr 29, 2021 at 11:47:33AM +0200, Bartosz Golaszewski wrote:
>
> ...
>
> > > > +/* We don't have mkdtempat()... :( */
> > >
> > > But we have tmpnam() / tmpnam_r(), why to reinvent it below?
> > >
> >
> > Because of this:
> >
> > $man tmpnam_r
> > ...
> > The created pathname has a directory prefix P_tmpdir.
> > ...
> >
> > And this:
> >
> > ./stdio.h:120:# define P_tmpdir "/tmp"
>
> Still you may advance the pointer by the length of P_tmpdir + 1.
>
> ...
>
> > > > +     for (i = 0; i < num_names; i++)
> > > > +             written += snprintf(buf + written, size - written,
> > > > +                                 "\"%s\", ", names[i] ?: "");
> > > > +     buf[size - 2] = '\0';
> > >
> > > Dunno if you can use asprintf() and actually replace NULL by "" in the original
> > > array. Ah, see you already using it somewhere else, why not here?
> > >
> >
> > Not sure what you mean, we can't use asprintf() to create a composite
> > string like what is needed here. Can you give me an example?
>
> I have got this after sending. Either you need to create a format string with
> va_args, or do it manually.
>
>

No can do, you can't create a va_list out of thin air.

Bart

> --
> With Best Regards,
> Andy Shevchenko
>
>