Solaris definition of struct std::lconv

[Jonathan Wakely]

On Wed, 31 Jul 2024 at 12:56, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
>
> Hi Rainer,
>
> I've been working on PR57585 and have added a new
> --enable-clocale=ieee_1003.1-2008
> configure option. That should work on Solaris 11.4 (e.g. cfarm216) but
> some members of the struct std::lconv are missing.
>
> In <iso/locale_iso.h> the definition of lconv has:
>
> /*
> * New in IEEE Std 1003.1-2001 for alignment with the ISO/IEC 9899:1999
> * standard.  Namespace and binary compatibility dictate that visibility
> * of these new members be limited.  Visibility is limited to a strictly
> * conforming ANSI C environment (-Xc) or if _LCONV_C99 is defined.
> */
> #if (defined(_STRICT_STDC) && defined(_STDC_C99)) || defined(_LCONV_C99)
>        char int_p_cs_precedes;
>        char int_p_sep_by_space;
>        char int_n_cs_precedes;
>        char int_n_sep_by_space;
>        char int_p_sign_posn;
>        char int_n_sign_posn;
> #endif
>
> This block is not enabled for C++, but it should be, because C++17
> incorporates the C99 standard library. So the C99 members of lconv
> should be present in C++17 too.
>
> Do you know if this is a known issue?
>
> I can work around it by defining _LCONV_C99 in the relevant .cc files,
> but it shouldn't be needed.

That works, but I already have:
#define _POSIX_C_SOURCE 200809L
which I would have expected to be enough to enable the block above.
POSIX.1-2008 is based on C99, so those members should be defined.

I guess the "namespace and binary compatibility" concerns override the
conformance requirements here?
Since these members only need to be acessed from inside libstdc++.so,
not in headers, defining _LCONV_C99 is fine.

This seems to be the only build failure I get with the new clocale
model on Solaris 11.4, so I'll start testing it.