wcscoll

int wcscoll( const wchar_t *lhs, const wchar_t *rhs );

Compares two null-terminated wide strings according to the collation order defined by the LC_COLLATE category of the currently installed locale.

Parameters

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

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

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

References

• C11 standard (ISO/IEC 9899:2011):
• 7.29.4.4.2 The wcscoll function (p: 433-434)
• C99 standard (ISO/IEC 9899:1999):
• 7.24.4.4.2 The wcscoll function (p: 379-380)

See also