thread_locale1.c - Per-thread locale demo
Posted by Anonymous on Tue 16th May 2023 15:58
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/*
 * thread_multi_locale1.c - Per-thread locale demo
 *
 * Written by Roland Mainz <roland.mainz@nrubsig.org>
 */

#define _XOPEN_SOURCE 700

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <locale.h>
#include <errno.h>

#define CURSED_GLIBC_DOES_NOT_HAVE_PRINTF_L 1

#if defined(_WIN32) && !defined(LC_GLOBAL_LOCATE)
#define EMULATE_POSIX_NEWLOCALE_ON_WINDOWS 1
#define CURSED_GLIBC_DOES_NOT_HAVE_PRINTF_L 1
#endif /* defined(_WIN32) && !defined(LC_GLOBAL_LOCATE) */


#if EMULATE_POSIX_NEWLOCALE_ON_WINDOWS
#include <xlocinfo.h>
typedef _locale_t locale_t;


#define LC_ALL_MASK     (LC_ALL)

locale_t newlocale(int mask, const char * locale, locale_t base_not_implemented)
{
        return _create_locale(mask, locale);
}

locale_t uselocale(locale_t newloc)
{
        locale_t old_locale = _get_current_locale();

        /*
         * uselocale() sets the thread's locale by definition, so
         * unconditionally use thread-local locale
         */
        _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);

#define ElementsInArray(x)   (sizeof(x) / sizeof((x)[0]))
        /*
         * sets all categories - right now our poor man's emulation
         * can't do it better
         */
        for(int i=0 ; i < ElementsInArray(newloc->locinfo->lc_category) ; i++) {
                const char *curr_ln = newloc->locinfo->lc_category[1].locale;
#if 0
                (void)fprintf(stderr, "switching to locale %d/|%s|\n",
                        i, curr_ln);
#endif
                setlocale(i, curr_ln);
        }

        /* return the old locale_t */
        return old_locale;
}

void freelocale(locale_t locobj)
{
        _free_locale(locobj);
}
#endif /* EMULATE_POSIX_NEWLOCALE_ON_WINDOWS */

#ifdef __GLIBC__
/* { BSD, MacOSX, Illumos, ... } do not need this! */
#define CURSED_GLIBC_DOES_NOT_HAVE_PRINTF_L
#endif

#ifdef CURSED_GLIBC_DOES_NOT_HAVE_PRINTF_L
#include <stdarg.h>
#include <errno.h>
#endif /* CURSED_GLIBC_DOES_NOT_HAVE_PRINTF_L */

#ifdef CURSED_GLIBC_DOES_NOT_HAVE_PRINTF_L
/* cursed glibc does not provide |printf_l()| */
int vprintf_l(locale_t loc, const char *format, va_list ap)
{
        locale_t prev_loc;
        int ret;
        int saved_errno;

        prev_loc = uselocale(loc);

        ret = vprintf(format, ap);
        saved_errno = errno;

        (void)uselocale(prev_loc);

        errno = saved_errno;
        return ret;
}

int printf_l(locale_t loc, const char *format, ...)
{
        va_list args;
        int res;

        va_start(args, format);
        res = vprintf_l(loc, format, args);
        va_end(args);

        return res;
}
#endif /* CURSED_GLIBC_DOES_NOT_HAVE_PRINTF_L */


int main(int ac, char *av[])
{
        locale_t my_en_l;
        locale_t my_de_l;
        double x;

        (void)puts("# thread_multi_locale1: start"
#ifdef EMULATE_POSIX_NEWLOCALE_ON_WINDOWS
        " (emulated)"
#endif /* EMULATE_POSIX_NEWLOCALE_ON_WINDOWS */
        ".");

#if EMULATE_POSIX_NEWLOCALE_ON_WINDOWS
        my_en_l = newlocale(LC_ALL_MASK, "C", NULL);
        my_de_l = newlocale(LC_ALL_MASK, "German", NULL);
#else
        my_en_l = newlocale(LC_ALL_MASK, "en_US.UTF-8", NULL);
        my_de_l = newlocale(LC_ALL_MASK, "de_DE.UTF-8", NULL);
#endif /* EMULATE_POSIX_NEWLOCALE_ON_WINDOWS */
        if ((my_en_l == (locale_t)0) || (my_de_l == (locale_t)0)) {
                fprintf(stderr, "Could not create locale object [%s], %tx/%tx",
                        strerror(errno),
                        (ptrdiff_t)((char*)my_en_l-0),
                        (ptrdiff_t)((char*)my_de_l-0));
                return EXIT_FAILURE;
        }
#if 0
        (void)printf("de_DE locale decimal_point=|%s|\n",
                my_de_l->locinfo->lconv->decimal_point);
#endif
        x = 123456.789123456789;
        (void)printf_l(my_en_l, "%8.8f\n", x);
        (void)printf_l(my_de_l, "%8.8f\n", x);

        /*
         * If we use |uselocale()| we must set the current thread
         * locale to something else before freeing the current
         * locale_t object!!
         */
        freelocale(my_de_l);
        freelocale(my_en_l);

        (void)puts("# thread_multi_locale1: done.");

        return EXIT_SUCCESS;
}