std::wcsncpy

 

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>
wchar_t *wcsncpy( wchar_t *dest, const wchar_t *src, std::size_t count );

Copies at most count characters of the wide string pointed to by src (including the terminating null wide character) to wide character array pointed to by dest.

If count is reached before the entire string src was copied, the resulting wide character array is not null-terminated.

If, after copying the terminating null wide character from src, count is not reached, additional null wide characters are written to dest until the total of count characters have been written.

If the strings overlap, the behavior is undefined.

Parameters

dest	-	pointer to the wide character array to copy to
src	-	pointer to the wide string to copy from
count	-	maximum number of wide characters to copy

Return value

dest

Notes

In typical usage, count is the size of the destination array.

Example

Run this code

#include <iostream>
#include <cwchar>
 
int main()
{
    wchar_t src[] = L"hi";
    wchar_t dest[6] = {L'a', L'b', L'c', L'd', L'e', L'f'};
 
    std::wcsncpy(dest, src, 5); // this will copy hi and repeat \0 three times
 
    std::wcout << "The contents of dest are: ";
    for(wchar_t c : dest) {
        if(c)
            std::wcout << c << ' ';
        else
            std::wcout << "\\0" << ' ';
    }
    std::wcout << '\n';
}

Output:

The contents of dest are: h i \0 \0 \0 f

See also

wcscpy	copies one wide string to another (function)
wmemcpy	copies a certain amount of wide characters between two non-overlapping arrays (function)
strncpy	copies a certain amount of characters from one string to another (function)
C documentation for wcsncpy