strcoll, wcscoll, _mbscoll, _strcoll_l, _wcscoll_l, _mbscoll_l

Article
06/05/2017

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The latest version of this topic can be found at strcoll, wcscoll, _mbscoll, _strcoll_l, _wcscoll_l, _mbscoll_l.

Compares strings by using the current locale or a specified LC_COLLATE conversion-state category.

Important

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

Syntax

int strcoll(  
   const char *string1,  
   const char *string2   
);  
int wcscoll(  
   const wchar_t *string1,  
   const wchar_t *string2   
);  
int _mbscoll(  
   const unsigned char *string1,  
   const unsigned char *string2   
);  
int _strcoll_l(  
   const char *string1,  
   const char *string2,  
   _locale_t locale   
);  
int wcscoll_l(  
   const wchar_t *string1,  
   const wchar_t *string2,  
   _locale_t locale   
);  
int _mbscoll_l(  
   const unsigned char *string1,  
   const unsigned char *string2,  
   _locale_t locale   
);

Parameters

string1, string2
Null-terminated strings to compare.

locale
Locale to use.

Return Value

Each of these functions returns a value indicating the relationship of string1 to string2, as follows.

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

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

Remarks

Each of these functions performs a case-sensitive comparison of string1 and string2 according to the code page currently in use. These 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 string comparison.

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

The comparison of the two strings is a locale-dependent operation since each locale has different rules for ordering characters. The versions of these functions without the _l suffix use the current thread's locale for this locale-dependent behavior; the versions with the _l suffix are identical to the corresponding function without the suffix except that they use the locale passed in as a parameter instead of the current locale. For more information, see Locale.

Generic-Text Routine Mappings

TCHAR.H routine	_UNICODE & _MBCS not defined	_MBCS defined	_UNICODE defined
`_tcscoll`	`strcoll`	`_mbscoll`	`wcscoll`

Requirements

Routine	Required header
`strcoll`	<string.h>
`wcscoll`	<wchar.h>, <string.h>
`_mbscoll`, `_mbscoll_l`	<mbstring.h>
`_strcoll_l`	<string.h>
`_wcscoll_l`	<wchar.h>, <string.h>

For additional compatibility information, see Compatibility.

.NET Framework Equivalent

System::String::Compare

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