std::wmemcpy(3)

NAME
std::wmemcpy - std::wmemcpy

Synopsis
   Defined in header <cwchar>
   wchar_t* wmemcpy( wchar_t* dest, const wchar_t* src, std::size_t count );
   Copies exactly count successive wide characters from the wide character array
   pointed to by src to the wide character array pointed to by dest. If the objects
   overlap, the behavior is undefined. If count is zero, the function does nothing.

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

Return value
   dest

Notes
   This function's analog for byte strings is std::strncpy, not std::strcpy.
   This function is not locale-sensitive and pays no attention to the values of the
   wchar_t objects it copies: nulls as well as invalid characters are copied too.

Example
// Run this code
 #include <clocale>
 #include <cwchar>
 #include <iostream>
 #include <iterator>
 #include <locale>
 int main(void)
 {
     const wchar_t from1[] = L"नमसत";
     const wchar_t from2[] = L"Բարև";
     const std::size_t sz1 = std::size(from1);
     const std::size_t sz2 = std::size(from2);
     wchar_t to[sz1 + sz2];
     std::wmemcpy(to, from1, sz1); // copy from1, along with its null terminator
     std::wmemcpy(to + sz1, from2, sz2); // append from2, along with its null terminator
     std::setlocale(LC_ALL, "en_US.utf8");
     std::wcout.imbue(std::locale("en_US.utf8"));
     std::wcout << L"Wide array contains: ";
     for (std::size_t n = 0; n < std::size(to); ++n)
         if (to[n])
             std::wcout << to[n];
         else
             std::wcout << L"\\0";
     std::wcout << L'\n';
 }

Possible output:
 Wide array contains: नमसत\0Բարև\0

See also
   strncpy copies a certain amount of characters from one string to another
            (function)
            copies a certain amount of wide characters between two, possibly
   wmemmove overlapping, arrays
            (function)
   C documentation for
   wmemcpy