GetStringScripts function (winnls.h)

Article
10/13/2021

Provides a list of scripts used in the specified Unicode string.

Syntax

int GetStringScripts(
  [in]            DWORD   dwFlags,
  [in]            LPCWSTR lpString,
  [in]            int     cchString,
  [out, optional] LPWSTR  lpScripts,
  [in]            int     cchScripts
);

Parameters

[in] dwFlags

Flags specifying options for script retrieval.

Value	Meaning
GSS_ALLOW_INHERITED_COMMON	Retrieve "Qaii" (INHERITED) and "Zyyy" (COMMON) script information. This flag does not affect the processing of unassigned characters. These characters in the input string always cause a "Zzzz" (UNASSIGNED script) to appear in the script string.

Note By default, GetStringScripts ignores any inherited or common characters in the input string indicated by lpString. If GSS_ALLOW_INHERITED_COMMON is not set, neither "Qaii" nor "Zyyy" appears in the script string, even if the input string contains such characters. If GSS_ALLOW_INHERITED_COMMON is set, and if the input string contains inherited and/or common characters, "Qaii" and/or "Zyyy", respectively, appear in the script string. See the Remarks section.

[in] lpString

Pointer to the Unicode string to analyze.

[in] cchString

Size, in characters, of the Unicode string indicated by lpString. The application sets this parameter to -1 if the Unicode string is null-terminated. If the application sets this parameter to 0, the function retrieves a null Unicode string (L"\0") in lpScripts and returns 1.

[out, optional] lpScripts

Pointer to a buffer in which this function retrieves a null-terminated string representing a list of scripts, using the 4-character notation used in ISO 15924. Each script name consists of four Latin characters, and the names are retrieved in alphabetical order. Each name, including the last, is followed by a semicolon.

Alternatively, this parameter contains NULL if cchScripts is set to 0. In this case, the function returns the required size for the script buffer.

[in] cchScripts

Size, in characters, of the script buffer indicated by lpScripts.

Alternatively, the application can set this parameter to 0. In this case, the function retrieves NULL in lpScripts and returns the required size for the script buffer.

Return value

Returns the number of characters retrieved in the output buffer, including a terminating null character, if successful and cchScripts is set to a nonzero value. The function returns 1 to indicate that no script has been found, for example, when the input string only contains COMMON or INHERITED characters and GSS_ALLOW_INHERITED_COMMON is not set. Given that each found script adds five characters (four characters + delimiter), a simple mathematical operation provides the script count as (return_code - 1) / 5.

If the function succeeds and the value of cchScripts is 0, the function returns the required size, in characters including a terminating null character, for the script buffer. The script count is as described above.

This 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_BADDB. The function could not access the data. This situation should not normally occur, and typically indicates a bad installation, a disk problem, or the like.
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

This function is useful as part of a strategy to mitigate security issues related to internationalized domain names (IDNs).

The script determination is based on the script values published by the Unicode Consortium in http://www.unicode.org/Public/4.1.0/ucd/Scripts.txt, except that the unassigned characters have the value "Zzzz" (UNASSIGNED) instead of "Zyyy" (COMMON).

Here are some examples of the behavior of this function:

Input string		dwFlags	lpScripts	Scripts
Microsoft.com		0	Latn;	Latin
Microsoft.com		GSS_ALLOW_INHERITED_COMMON	Latn;Zyyy;	Latin + Common
Niño	004E 0069 0241 006F	GSS_ALLOW_INHERITED_COMMON	Latn;	Latin
Niño	Uses LATIN SMALL LETTER N WITH TILDE	GSS_ALLOW_INHERITED_COMMON	Latn;	Latin
Niño	004E 0069 006E 0303 006F	GSS_ALLOW_INHERITED_COMMON	Latn;Qaii;	Latin + Inherited
Niño	Uses COMBINING TILDE	GSS_ALLOW_INHERITED_COMMON	Latn;Qaii;	Latin + Inherited
Spооf	0053 0070 043e 043e 0066	0	Latn;Cyrl;	Latin + Cyrillic
Spооf	Uses CYRILLIC SMALL LETTER O	0	Latn;Cyrl;	Latin + Cyrillic
	U+f000	0	Zzzz;	Unassigned
	U+f000	GSS_ALLOW_INHERITED_COMMON	Zzzz;	Unassigned

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps \| UWP apps]
Minimum supported server	Windows Server 2008 [desktop apps \| UWP apps]
Target Platform	Windows
Header	winnls.h (include Windows.h)
Library	Kernel32.lib
DLL	Kernel32.dll