Re: Inconsistent results with libc sorting on Windows

[Juan José Santamaría Flecha]

On Fri, Aug 11, 2023 at 7:29 AM Noah Misch <n...@leadboat.com> wrote:

>
> The LCMapStringEx() solution is elegant.  I do see
>
> https://learn.microsoft.com/en-us/windows/win32/intl/handling-sorting-in-your-applications
> says, "If an application calls the function to create a sort key for a
> string
> containing an Arabic kashida, the function creates no sort key value."
> That's
> aggravating.
>

I think the problem there is that it is just poorly explained.
Take for example the attached program that compares "normal" and "kashida"
'Raħīm' taken from [1], you'll get:

c1 = c2
c2 = c1

meaning that "normal" and "kashida" are the same string. So, probably that
phrase should read something like: "If an application calls the function to
create a sort key for a string containing an Arabic kashida character, the
function will ignore that character and no sort key value will be generated
for it."

[1] https://en.wikipedia.org/wiki/Kashida

Regards,

Juan José Santamaría Flecha

#include "windows.h"
#include "stdio.h"

static char
comparison(int r)
{
    switch (r) {
    case 1:
        return '>';
    case -1:
        return '<';
    case 0:
        return '=';
    default:
        return '!';
    }
}

int
wmain(int argc, wchar_t* argv[])
{
    const wchar_t *s1 = L"\u0631\u062d\u064a\u0645";
    const wchar_t *s2 = 
L"\u0631\u062d\u0640\u0640\u0640\u0640\u0640\u0640\u064a\u0645";
    int     len;
    wchar_t c1[13];
    wchar_t c2[13];
    int     result;

    len = LCMapStringEx(L"es-US", LCMAP_SORTKEY, s1, -1, c1, 13, NULL, NULL, 0);
    len = LCMapStringEx(L"es-US", LCMAP_SORTKEY, s2, -1, c2, 13, NULL, NULL, 0);

    result = memcmp(c1, c2, 13);
    printf("c1 %c c2\n", comparison(result));
    result = memcmp(c2, c1, 13);
    printf("c2 %c c1\n", comparison(result));

    return 0;
}