GetStringTypeA function (winnls.h)

Deprecated. Retrieves character type information for the characters in the specified source string. For each character in the string, the function sets one or more bits in the corresponding 16-bit element of the output array. Each bit identifies a given character type, for example, letter, digit, or neither.

Caution  Using the GetStringTypeA function incorrectly can compromise the security of your application. To avoid a buffer overflow, the application must set the output buffer size correctly. For more security information, see Security Considerations: Windows User Interface.



BOOL GetStringTypeA(
  [in]  LCID   Locale,
  [in]  DWORD  dwInfoType,
  [in]  LPCSTR lpSrcStr,
  [in]  int    cchSrc,
  [out] LPWORD lpCharType


[in] Locale

Locale identifier that specifies the locale. You can use the MAKELCID macro to create a locale identifier or use one of the following predefined values.

Windows Vista and later: The following custom locale identifiers are also supported.

[in] dwInfoType

Flags specifying the character type information to retrieve. For possible flag values, see the dwInfoType parameter of GetStringTypeW. For detailed information about the character type bits, see Remarks for GetStringTypeW.

[in] lpSrcStr

Pointer to the ANSI string for which to retrieve the character types. The string can be a double-byte character set (DBCS) string if the supplied locale is appropriate for DBCS. The string is assumed to be null-terminated if cchSrc is set to any negative value.

[in] cchSrc

Size, in characters, of the string indicated by lpSrcStr. If the size includes a terminating null character, the function retrieves character type information for that character. If the application sets the size to any negative integer, the source string is assumed to be null-terminated and the function calculates the size automatically with an additional character for the null termination.

[out] lpCharType

Pointer to an array of 16-bit values. The length of this array must be large enough to receive one 16-bit value for each character in the source string. If cchSrc is not a negative number, lpCharType should be an array of words with cchSrc elements. If cchSrc is set to a negative number, lpCharType is an array of words with lpSrcStr + 1 elements. When the function returns, this array contains one word corresponding to each character in the source string.

Return value

Returns a nonzero value if successful, or 0 otherwise. To get extended error information, the application can call GetLastError, which can return one of the following error codes:

  • ERROR_INVALID_FLAGS. The values supplied for flags were not valid.
  • ERROR_INVALID_PARAMETER. Any of the parameter values was invalid.


For an overview of the use of the string functions, see Strings.

This function converts the source string to Unicode and calls the corresponding GetStringTypeW function. Thus the words in the output buffer correspond not to the original ANSI string but to its Unicode equivalent. The conversion from ANSI to Unicode can result in a change in string length, for example, a pair of ANSI characters can map to a single Unicode character. Therefore, the correspondence between the words in the output buffer and the characters in the original ANSI string is not one-to-one in all cases, for example, multibyte strings. Thus GetStringTypeA is of limited use for multi-character strings. GetStringTypeW function and GetStringTypeEx are recommended instead.

When 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 (?).

The values of the lpSrcStr and lpCharType parameters must not be the same. If they are the same, the function fails with ERROR_INVALID_PARAMETER.

The Locale parameter is only used to perform string conversion to Unicode. It has nothing to do with the CTYPE* values supplied by the application. These values are solely determined by Unicode code points, and do not vary on a locale basis. For example, Greek letters are specified as C1_ALPHA for any value of Locale.

The Locale parameter is not used by the corresponding GetStringTypeW function. Because of the parameter difference, an application cannot automatically invoke the proper ANSI or Unicode version of a GetStringType* function through the use of the #define UNICODE switch. An application can circumvent this limitation by using GetStringTypeEx, which is the recommended function.


Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header winnls.h (include Windows.h)
Library Kernel32.lib
DLL Kernel32.dll

See also



National Language Support

National Language Support Functions