_mbsnbcoll, _mbsnbcoll_l, _mbsnbicoll, _mbsnbicoll_l

Статья
10/16/2008

Compares n bytes of two multibyte-character strings using multibyte code page information.

int _mbsnbcoll(
   const unsigned char *string1,
   const unsigned char *string2,
   size_t count 
);
int _mbsnbcoll_l(
   const unsigned char *string1,
   const unsigned char *string2,
   size_t count,
   _locale_t locale
);
int _mbsnbicoll(
   const unsigned char *string1,
   const unsigned char *string2,
   size_t count 
);
int _mbsnbicoll_l(
   const unsigned char *string1,
   const unsigned char *string2,
   size_t count,
   _locale_t locale
);

Параметры

string1, string2
Strings to compare.
count
Number of bytes to compare.
locale
Locale to use.

Возвращаемое значение

The return value indicates the relation of the substrings of string1 and string2.

Return value	Description
< 0	string1 substring less than string2 substring.
0	string1 substring identical to string2 substring.
> 0	string1 substring greater than string2 substring.

If string1 or string2 is NULL or count is greater than INT_MAX, the invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, these functions return _NLSCMPERROR and set errno to EINVAL. To use _NLSCMPERROR, include either String.h or Mbstring.h.

Заметки

Each of these functions collates, at most, the first count bytes in string1 and string2 and returns a value indicating the relationship between the resulting substrings of string1 and string2. If the final byte in the substring of string1 or string2 is a lead byte, it is not included in the comparison; these functions compare only complete characters in the substrings. _mbsnbicoll is a case-insensitive version of _mbsnbcoll. Like _mbsnbcmp and _mbsnbicmp, _mbsnbcoll and _mbsnbicoll collate the two multibyte-character strings according to the lexicographic order specified by the multibyte code page currently in use.

For some code pages and corresponding character sets, the order of characters in the character set might differ from the lexicographic character order. In the "C" locale, this is not the case: the order of characters in the ASCII character set is the same as the lexicographic order of the characters. However, in certain European code pages, for example, the character 'a' (value 0x61) precedes the character 'ä' (value 0xE4) in the character set, but the character 'ä' precedes the character 'a' lexicographically. To perform a lexicographic comparison of strings by bytes in such an instance, use _mbsnbcoll rather than _mbsnbcmp; to check only for string equality, use _mbsnbcmp.

Because the coll functions collate strings lexicographically for comparison, whereas the cmp functions simply test for string equality, the coll functions are much slower than the corresponding cmp versions. Therefore, the coll functions should be used only when there is a difference between the character set order and the lexicographic character order in the current code page and this difference is of interest for the comparison.

The output value is affected by the setting of the LC_CTYPE category setting of the locale; see setlocale for more information. The versions of these functions without the _l suffix use the current locale for this locale-dependent behavior; the versions with the _l suffix are identical except that they use the locale parameter passed in instead. For more information, see Locale.

Generic-Text Routine Mappings

Tchar.h routine	_UNICODE and _MBCS not defined	_MBCS defined	_UNICODE defined
_tcsncoll	_strncoll	_mbsnbcoll	_wcsncoll
_tcsncoll_l	_strncoll, _wcsncoll, _mbsncoll, _strncoll_l, _wcsncoll_l, _mbsncoll_l	_mbsnbcoll_l	_wcsncoll_l
_tcsnicoll	_strnicoll	_mbsnbicoll	_wcsnicoll
_tcsnicoll_l	_strnicoll_l	_mbsnbicoll_l	_wcsnicoll_l