std::wcscoll

 

C++

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Technical Specifications

 

Strings library

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Null-terminated wide strings

Functions
Character manipulation
iswalnum iswalpha iswlower iswupper iswdigit iswxdigit iswblank (C++11) wctype iswctype	iswcntrl iswgraph iswspace iswprint iswpunct towlower towupper wctrans towctrans
Conversions to numeric formats
wcstolwcstoll wcstoulwcstoull	wcstofwcstodwcstold wcstoimaxwcstouimax (C++11)(C++11)
String manipulation
wcslen wcscpy wcsncpy wcscat wcsncat wcscmp wcscoll wcsncmp	wcsxfrm wcschr wcsrchr wcspbrk wcsspn wcscspn wcsstr wcstok
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wmemmove
wmemcmp
wmemchr
wmemset

 

Defined in header <cwchar>
int wcscoll( const wchar_t* lhs, const wchar_t* rhs );

Compares two null-terminated wide strings according to the locale most recently installed by std::setlocale, as defined by the LC_COLLATE category.

Parameters

lhs, rhs

-

pointers to the null-terminated wide strings to compare

Return value

Negative value if lhs is less than (precedes) rhs.

​0​ if lhs is equal to rhs.

Positive value if lhs is greater than (follows) rhs.

Notes

Collation order is the dictionary order: the position of the letter in the national alphabet (its equivalence class) has higher priority than its case or variant. Within an equivalence class, lowercase characters collate before their uppercase equivalents and locale-specific order may apply to the characters with diacritics. In some locales, groups of characters compare as single collation units. For example, "ch" in Czech follows "h" and precedes "i", and "dzs" in Hungarian follows "dz" and precedes "g".

Example

Run this code

#include <iostream>
#include <clocale>
 
void try_compare(const wchar_t* p1, const wchar_t* p2)
{
    if(std::wcscoll(p1, p2) < 0)
         std::wcout << p1 << " before " << p2 << '\n';
    else
         std::wcout << p2 << " before " << p1 << '\n';
}
 
int main()
{
    std::setlocale(LC_ALL, "en_US.utf8");
    std::wcout << "In the American locale: ";
    try_compare(L"hrnec", L"chrt");
 
    std::setlocale(LC_COLLATE, "cs_CZ.utf8");
    std::wcout << "In the Czech locale: ";
    try_compare(L"hrnec", L"chrt");
 
    std::setlocale(LC_COLLATE, "en_US.utf8");
    std::wcout << "In the American locale: ";
    try_compare(L"år", L"ängel");
 
    std::setlocale(LC_COLLATE, "sv_SE.utf8");
    std::wcout << "In the Swedish locale: ";
    try_compare(L"år", L"ängel");
}

Output:

In the American locale: chrt before hrnec
In the Czech locale: hrnec before chrt
In the American locale: ängel before år
In the Swedish locale: år before ängel

See also

strcoll	compares two strings in accordance to the current locale (function)
do_compare [virtual]	compares two strings using this facet's collation rules (virtual protected member function of std::collate)
wcsxfrm	transform a wide string so that wcscmp would produce the same result as wcscoll (function)
C documentation for wcscoll