std::wmemset

 

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
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wmemcmp
wmemchr
wmemset

 

Defined in header <cwchar>
wchar_t* wmemset( wchar_t* dest, wchar_t ch, std::size_t count );

Copies the wide character ch into each of the first count wide characters of the wide character array pointed to by dest.

If overflow occurs, the behavior is undefined.

If count is zero, the function does nothing.

Parameters

dest	-	pointer to the wide character array to fill
ch	-	fill wide character
count	-	number of wide characters to fill

Return value

Returns a copy of dest

Notes

This function is not locale-sensitive and pays no attention to the values of the wchar_t objects it writes: nulls as well as invalid wide characters are written too.

Example

Run this code

#include <iostream>
#include <cwchar>
#include <clocale>
#include <locale>
 
int main()
{
    wchar_t ar[4] = {L'1', L'2', L'3', L'4'};
    std::wmemset(ar, L'\U0001f34c', 2); // replaces [12] with the 🍌 bananas
    std::wmemset(ar+2, L'蕉', 2); // replaces [34] with the 蕉 bananas
 
    std::setlocale(LC_ALL, "en_US.utf8");
    std::wcout.imbue(std::locale("en_US.utf8"));
    std::wcout << std::wstring(ar, 4) << '\n';
}

Possible output:

🍌🍌蕉蕉

See also

memset	fills a buffer with a character (function)
wmemcpy	copies a certain amount of wide characters between two non-overlapping arrays (function)
fill_n	copy-assigns the given value to N elements in a range (function template)
C documentation for wmemset