GetDateFormatW function (datetimeapi.h)
Formats a date as a date string for a locale specified by the locale identifier. The function formats either a specified date or the local system date.
Syntax
int GetDateFormatW(
[in] LCID Locale,
[in] DWORD dwFlags,
[in, optional] const SYSTEMTIME *lpDate,
[in, optional] LPCWSTR lpFormat,
[out, optional] LPWSTR lpDateStr,
[in] int cchDate
);
Parameters
[in] Locale
Locale identifier that specifies the locale this function formats the date string for. You can use the MAKELCID macro to create a locale identifier or use one of the following predefined values.
- LOCALE_CUSTOM_DEFAULT
- LOCALE_CUSTOM_UI_DEFAULT
- LOCALE_CUSTOM_UNSPECIFIED
- LOCALE_INVARIANT
- LOCALE_SYSTEM_DEFAULT
- LOCALE_USER_DEFAULT
[in] dwFlags
Flags specifying date format options. For detailed definitions, see the dwFlags parameter of GetDateFormatEx.
[in, optional] lpDate
Pointer to a SYSTEMTIME structure that contains the date information to format. The application sets this parameter to NULL if the function is to use the current local system date.
[in, optional] lpFormat
Pointer to a format picture string that is used to form the date. Possible values for the format picture string are defined in Day, Month, Year, and Era Format Pictures.
The function uses the specified locale only for information not specified in the format picture string, for example, the day and month names for the locale. The application can set this parameter to NULL to format the string according to the date format for the specified locale.
[out, optional] lpDateStr
Pointer to a buffer in which this function retrieves the formatted date string.
[in] cchDate
Size, in characters, of the lpDateStr buffer. The application can set this parameter to 0 to return the buffer size required to hold the formatted date string. In this case, the buffer indicated by lpDateStr is not used.
Return value
Returns the number of characters written to the lpDateStr buffer if successful. If the cchDate parameter is set to 0, the function returns the number of characters required to hold the formatted date string, including the terminating null character.
The function returns 0 if it does not succeed. To get extended error information, the application can call GetLastError, which can return one of the following error codes:
- ERROR_INSUFFICIENT_BUFFER. A supplied buffer size was not large enough, or it was incorrectly set to NULL.
- ERROR_INVALID_FLAGS. The values supplied for flags were not valid.
- ERROR_INVALID_PARAMETER. Any of the parameter values was invalid.
Remarks
When the ANSI version of this function is used with a Unicode-only locale identifier, the function can succeed because the operating system uses the system code page. However, characters that are undefined in the system code page appear in the string as a question mark ("?").
Starting with Windows 8: GetDateFormat is declared in Datetimeapi.h. Before Windows 8, it was declared in Winnls.h.
Note
The datetimeapi.h header defines GetDateFormat as an alias that automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that is not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | datetimeapi.h |
| Library | Kernel32.lib |
| DLL | Kernel32.dll |