Home/ Questions/Q 6388495
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-25T03:17:08+00:00

I’m using the Windows API GetNumberFormatEx to format some numbers for display with the

  • 0

I’m using the Windows API GetNumberFormatEx to format some numbers for display with the appropriate localization choices for the current user (e.g., to make sure they have the right separators in the right places). This is trivial when you want exactly the user default.

But in some cases I sometimes have to override the number of digits after the radix separator. That requires providing a NUMBERFMT structure. What I’d like to do is to call an API that returns the NUMBERFMT populated with the appropriate defaults for the user, and then override just the fields I need to change. But there doesn’t seem to be an API to get the defaults.

Currently, I’m calling GetLocaleInfoEx over and over and then translating that data into the form NUMBERFMT requires.

NUMBERFMT fmt = {0};
::GetLocaleInfoEx(LOCALE_NAME_USER_DEFAULT,
                  LOCALE_IDIGITS | LOCALE_RETURN_NUMBER,
                  reinterpret_cast<LPWSTR>(&fmt.NumDigits),
                  sizeof(fmt.NumDigits)/sizeof(WCHAR));
::GetLocaleInfoEx(LOCALE_NAME_USER_DEFAULT,
                  LOCALE_ILZERO | LOCALE_RETURN_NUMBER,
                  reinterpret_cast<LPWSTR>(&fmt.LeadingZero),
                  sizeof(fmt.LeadingZero)/sizeof(WCHAR));
WCHAR szGrouping[32] = L"";
::GetLocaleInfoEx(LOCALE_NAME_USER_DEFAULT, LOCALE_SGROUPING, szGrouping,
                  ARRAYSIZE(szGrouping));
if (::lstrcmp(szGrouping, L"3;0") == 0 ||
    ::lstrcmp(szGrouping, L"3") == 0
) {
    fmt.Grouping = 3;
} else if (::lstrcmp(szGrouping, L"3;2;0") == 0) {
    fmt.Grouping = 32;
} else {
    assert(false);  // unexpected grouping string
}
WCHAR szDecimal[16] = L"";
::GetLocaleInfoEx(LOCALE_NAME_USER_DEFAULT, LOCALE_SDECIMAL, szDecimal,
                  ARRAYSIZE(szDecimal));
fmt.lpDecimalSep = szDecimal;
WCHAR szThousand[16] = L"";
::GetLocaleInfoEx(LOCALE_NAME_USER_DEFAULT, LOCALE_STHOUSAND, szThousand,
                  ARRAYSIZE(szThousand));
fmt.lpThousandSep = szThousand;
::GetLocaleInfoEx(LOCALE_NAME_USER_DEFAULT,
                  LOCALE_INEGNUMBER | LOCALE_RETURN_NUMBER,
                  reinterpret_cast<LPWSTR>(&fmt.NegativeOrder),
                  sizeof(fmt.NegativeOrder)/sizeof(WCHAR));

Isn’t there an API that already does this?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    I just wrote some code to do this last week. Alas, there does not seem to be a GetDefaultNumberFormat(LCID lcid, NUMBERFMT* fmt) function; you will have to write it yourself as you’ve already started. On a side note, the grouping string has a well-defined format that can be easily parsed; your current code is wrong for “3” (should be 30) and obviously will fail on more exotic groupings (though this is probably not much of a concern, really).

    • 0