std::basic_string_view<CharT,Traits>::copy

size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const;		(since C++17) (until C++20)
constexpr size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const;		(since C++20)

Copies the substring [pos, pos + rcount) to the character array pointed to by dest, where rcount is the smaller of count and size() - pos.

Equivalent to Traits::copy(dest, data() + pos, rcount).

dest	-	pointer to the destination character string
pos	-	position of the first character
count	-	requested substring length

Number of characters copied.

std::out_of_range if pos > size().

Linear in rcount.