_strncoll, _wcsncoll, _mbsncoll, _strncoll_l, _wcsncoll_l, _mbsncoll_l

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06/05/2017

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The latest version of this topic can be found at _strncoll, _wcsncoll, _mbsncoll, _strncoll_l, _wcsncoll_l, _mbsncoll_l.

Compares strings by using locale-specific information.

Important

_mbsncoll and _mbsncoll_l cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported with /ZW.

Syntax

int _strncoll(  
   const char *string1,  
   const char *string2,  
   size_t count   
);  
int _wcsncoll(  
   const wchar_t *string1,  
   const wchar_t *string2,  
   size_t count   
);  
int _mbsncoll(  
   const unsigned char *string1,  
   const unsigned char *string2,  
   size_t count   
);  
int _strncoll_l(  
   const char *string1,  
   const char *string2,  
   size_t count,  
   _locale_t locale  
);  
int _wcsncoll_l(  
   const wchar_t *string1,  
   const wchar_t *string2,  
   size_t count,  
   _locale_t locale  
);  
int _mbsncoll_l(  
   const unsigned char *string1,  
   const unsigned char *string2,  
   size_t count,  
   _locale_t locale  
);

Parameters

string1, string2
Null-terminated strings to compare.

count
The number of characters to compare.

locale
The locale to use.

Return Value

Each of these functions returns a value that indicates the relationship of the substrings of string1 and string2, as follows.

Return value	Relationship of string1 to string2
< 0	`string1` is less than `string2`.
0	`string1` is identical to `string2`.
> 0	`string1` is greater than `string2`.

Each of these functions returns _NLSCMPERROR. To use _NLSCMPERROR, include either STRING.h or MBSTRING.h. _wcsncoll can fail if either string1 or string2 contains wide-character codes that are outside the domain of the collating sequence. When an error occurs, _wcsncoll may set errno to EINVAL. To check for an error on a call to _wcsncoll, set errno to 0 and then check errno after you call _wcsncoll.

Remarks

Each of these functions performs a case-sensitive comparison of the first count characters in string1 and string2, according to the code page that's currently in use. Use these functions only when there is a difference between the character set order and the lexicographic character order in the code page, and when this difference is of interest for the string comparison. The character set order is locale-dependent. The versions of these functions that don't have the _l suffix use the current locale, but the versions that have the _l suffix use the locale that's passed in. For more information, see Locale.

All of these functions validate their parameters. If either string1 or string2 is a null pointer, 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.

Generic-Text Routine Mappings

TCHAR.H routine	_UNICODE & _MBCS not defined	_MBCS defined	_UNICODE defined
`_tcsnccoll`	`_strncoll`	`_mbsncoll`	`_wcsncoll`
`_tcsncoll`	`_strncoll`	_mbsnbcoll	`_wcsncoll`

Requirements

Routine	Required header
`_strncoll`, `_strncoll_l`	<string.h>
`_wcsncoll`, `_wcsncoll_l`	<wchar.h> or <string.h>
`_mbsncoll`, `_mbsncoll_l`	<mbstring.h>

For additional compatibility information, see Compatibility.

.NET Framework Equivalent

System::String::Compare

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