Re: PG compilation error with Visual Studio 2015/2017/2019 - Mailing list pgsql-hackers

On Wed, Apr 15, 2020 at 11:58 PM Juan José Santamaría Flecha
<juanjo.santamaria@gmail.com> wrote:
>
> On Wed, Apr 15, 2020 at 4:46 PM Ranier Vilela <ranier.vf@gmail.com> wrote:
>>
>> Em qua., 15 de abr. de 2020 às 03:08, davinder singh <davindersingh2692@gmail.com> escreveu:
>>>
>>>
>>>> 5. Why call _create_locale if _WIN32_WINNT >= 0x0600 is true and loct is not used?
>>>
>>> _create_locale can take bigger input than GetLocaleInfoEx. But we are interested in
>>> language[_country-region[.code-page]]. We are using _create_locale to validate
>>> the given input. The reason is we can't verify the locale name if it is appended with
>>> code-page by using GetLocaleInfoEx. So before parsing, we verify if the whole input
>>> locale name is valid by using _create_locale. I hope that answers your question.
>>
>> Understood. In this case, _create_locale, is being used only to validate the input.
>> Perhaps, in addition, you could create an additional function, which only validates winlocname, without having to
createstructures or use malloc, to be used when _WIN32_WINNT> = 0x0600 is true, but it is only a suggestion, if you
thinkit is necessary. 
>
>
> Looking at the comments for IsoLocaleName() I see: "MinGW headers declare _create_locale(), but msvcrt.dll lacks that
symbol".This is outdated [1][2], and  _create_locale() could be used from Windows 8, but I think we should use
GetLocaleInfoEx()as a complete alternative to  _create_locale(). 
>

I see some differences in the output when _create_locale() is used vs.
when GetLocaleInfoEx() is used.  Forex.

Set LC_MESSAGES="English_New Zealand";

-- returns en-NZ, then code changes it to en_NZ when _create_locale()
is used whereas GetLocaleInfoEx returns error.

Set LC_MESSAGES="English_Republic of the Philippines";

-- returns en-PH, then code changes it to en_PH when _create_locale()
is used whereas GetLocaleInfoEx returns error.

Set LC_MESSAGES="English_New Zealand";

-- returns en-NZ, then code changes it to en_NZ when _create_locale()
is used whereas GetLocaleInfoEx returns error.

Set LC_MESSAGES="French_Canada";

--returns fr-CA when _create_locale() is used whereas GetLocaleInfoEx
returns error.

The function IsoLocaleName() header comment says "Convert a Windows
setlocale() argument to a Unix-style one", so I was expecting above
cases which gives valid values with _create_locale() should also work
with GetLocaleInfoEx().  If it is fine for GetLocaleInfoEx() to return
an error for the above cases, then we need an explanation of the same
and probably add a few comments as well.  So, I am not sure if we can
conclude that GetLocaleInfoEx() is an alternative to _create_locale()
at this stage.

I have used the attached hack to make _create_locale work on the
latest MSVC.  Just to be clear this is mainly for the purpose of
testing the behavior _create_locale.

On the code side,
+ GetLocaleInfoEx(wc_locale_name, LOCALE_SNAME, (LPWSTR) &buffer,
+ LOCALE_NAME_MAX_LENGTH);

  /* Locale names use only ASCII, any conversion locale suffices. */
- rc = wchar2char(iso_lc_messages, loct->locinfo->locale_name[LC_CTYPE],
- sizeof(iso_lc_messages), NULL);
+ rc = wchar2char(iso_lc_messages, buffer, sizeof(iso_lc_messages), NULL);

Check the return value of GetLocaleInfoEx and if it is successful,
then only use wchar2char, otherwise, this function will return an
empty string ("") instead of NULL.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com