locale-test.c

#define __USE_MINGW_ANSI_STDIO 1
#include <stdint.h>
#include <stdio.h>
#include <locale.h>

int main()
{
	_locale_t c = _create_locale(LC_ALL, "C");
	_locale_t fr = _create_locale(LC_ALL, "french");

	printf("The decimal point separator is '%s'\n", localeconv()->decimal_point);

	printf("%lld %jd %zd %.1f\n", 1ll, (intmax_t)1, (size_t)1, 1.5);
	__mingw_printf("%lld %jd %zd %.1f\n", 1ll, (intmax_t)1, (size_t)1, 1.5);
	_printf_l("%lld %jd %zd %.1f\n", c, 1ll, (intmax_t)1, (size_t)1, 1.5);
	_printf_l("%lld %jd %zd %.1f\n", fr, 1ll, (intmax_t)1, (size_t)1, 1.5);

	if (!setlocale(LC_ALL, "french")) {
		printf("Can't change locale\n");
		return 1;
	}
	printf("The decimal point separator is '%s'\n", localeconv()->decimal_point);

	printf("%lld %jd %zd %.1f\n", 1ll, (intmax_t)1, (size_t)1, 1.5);
	__mingw_printf("%lld %jd %zd %.1f\n", 1ll, (intmax_t)1, (size_t)1, 1.5);
	_printf_l("%lld %jd %zd %.1f\n", c, 1ll, (intmax_t)1, (size_t)1, 1.5);
	_printf_l("%lld %jd %zd %.1f\n", fr, 1ll, (intmax_t)1, (size_t)1, 1.5);
}

// Output:
//   The decimal point separator is '.'
//   1 1 1 1.5
//   1 1 1 1.5
//   1 jd zd 0.0
//   1 jd zd 0,0
//   The decimal point separator is ','
//   1 1 1 1,5
//   1 1 1 1,5
//   1 jd zd 0.0
//   1 jd zd 0,0