std::wmemchr

 

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
Array manipulation
wmemcpy
wmemmove
wmemcmp
wmemchr
wmemset

 

Defined in header <cwchar>
const wchar_t* wmemchr( const wchar_t* ptr, wchar_t ch, std::size_t count );
wchar_t* wmemchr(       wchar_t* ptr, wchar_t ch, std::size_t count );

Locates the first occurrence of wide character ch in the initial count wide characters of the wide character array pointed to by ptr.

If count is zero, the function returns a null pointer.

Parameters

ptr	-	pointer to the wide character array to be examined
ch	-	wide character to search for
count	-	number of wide characters to examine

Return value

Pointer to the location of the wide character, or a null pointer if no such character is found.

Example

Run this code

#include <iostream>
#include <cwchar>
#include <clocale>
#include <locale>
 
int main()
{
    const wchar_t str[] = L"诺不轻信，故人不负我\0诺不轻许，故我不负人。";
    wchar_t target = L'许';
    const std::size_t sz = sizeof str / sizeof *str;
    if (const wchar_t* result = std::wmemchr(str, target, sz)) {
        std::setlocale(LC_ALL, "en_US.utf8");
        std::wcout.imbue(std::locale("en_US.utf8"));
        std::wcout << "Found '" << target
                   << "' at position " << result - str << "\n";
    }
}

Possible output:

Found '许' at position 14

See also

memchr	searches an array for the first occurrence of a character (function)
strchr	finds the first occurrence of a character (function)
wcschr	finds the first occurrence of a wide character in a wide string (function)
findfind_iffind_if_not (C++11)	finds the first element satisfying specific criteria (function template)
C documentation for wmemchr