Re: [PATCH] libstdc++: testsuite: avoid predictable mkstemp

[Jonathan Wakely <jwakely@redhat.com>]

On Tue, 5 Jul 2022 at 10:10, Alexandre Oliva via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> On Jun 27, 2022, Alexandre Oliva <oliva@adacore.com> wrote:
>
> > On Jun 23, 2022, Jonathan Wakely <jwakely@redhat.com> wrote:
> >> The attached makes this a bit more efficient, and makes more of the
> >> code common to the mkstemp and non-mkstmp branches. I'll wait to hear
> >> back from you before pushing it (since it has Joel's name on the
> >> patch).
>
> > Thanks, I've given it a spin, both trunk and gcc-11, and I confirm it
> > works for us.
>
> The bad news is that it broke on some other systems I didn't test back
> then.  It turns out the type cast for the ::getpid result was not just
> because it was passed to printf before :-/

Ah, whoops.

I did check that POSIX requires pid_t to be a signed integer type, but
that doesn't mean it's always true for all GCC targets.

>
>
> libstdc++: testsuite: cast getpid result
>
> On vxworks, in kernel mode, getpid's return type is a pointer type, so
> std::to_string on it fails overload resolution.  Restore the type cast
> from the original patch that suggested adding the pid.
>
> Regstrapped on x86_64-linux-gnu, also tested on aarch64-rtems6.0 and
> ppc64-vx7r2.  I'm going ahead and checking this in as obvious.  Please
> let me know if you'd prefer this to be fixed in a different way.

The cast itself is fine, but I'd like a comment like "N.B. pid_t is a
pointer on vxworks" so I don't "simplify" it again.

Thanks.