Defined in header <wchar.h>
int wcscmp( const wchar_t *lhs, const wchar_t *rhs );
(since C95)

Compares two null-terminated wide strings lexicographically.

The sign of the result is the sign of the difference between the values of the first pair of wide characters that differ in the strings being compared.

The behavior is undefined if lhs or rhs are not pointers to null-terminated wide strings.


lhs, rhs - pointers to the null-terminated wide strings to compare

Return value

Negative value if lhs appears before rhs in lexicographical order.

Zero if lhs and rhs compare equal.

Positive value if lhs appears after rhs in lexicographical order.


This function is not locale-sensitive, unlike wcscoll, and the order may not be meaningful when characters from different Unicode blocks are used together or when the order of code units does not match any collation order.


#include <wchar.h>
#include <stdio.h>
#include <locale.h>
void demo(const wchar_t* lhs, const wchar_t* rhs)
    int rc = wcscmp(lhs, rhs);
    const char *rel = rc < 0 ? "precedes" : rc > 0 ? "follows" : "equals";
    setlocale(LC_ALL, "en_US.utf8");
    printf("[%ls] %s [%ls]\n", lhs, rel, rhs);
int main(void)
    const wchar_t* string = L"どうもありがとうございます";
    demo(string, L"どうも");
    demo(string, L"助かった");
    demo(string + 9, L"ありがとうございます" + 6);

Possible output:

[どうもありがとうございます] follows [どうも]
[どうもありがとうございます] precedes [助かった]
[ざいます] equals [ざいます]


  • C11 standard (ISO/IEC 9899:2011):
    • The wcscmp function (p: 433)
  • C99 standard (ISO/IEC 9899:1999):
    • The wcscmp function (p: 379)

See also

compares a certain amount of characters from two wide strings
compares a certain amount of wide characters from two arrays
compares two strings
compares two wide strings in accordance to the current locale
C++ documentation for wcscmp

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