std::basic_string_view<CharT,Traits>::copy
Min standard notice:
Copies the substring [pos,pos + rcount) to the character array pointed to by dest, where rcount is the smaller of count and size() - pos.
# Declarations
size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const;
(since C++17) (constexpr since C++20)
# Parameters
dest: pointer to the destination character stringcount: requested substring lengthpos: position of the first character
# Return value
Number of characters copied.
# Example
#include <array>
#include <cstddef>
#include <iostream>
#include <stdexcept>
#include <string_view>
int main()
{
constexpr std::basic_string_view<char> source{"ABCDEF"};
std::array<char, 8> dest;
std::size_t count{}, pos{};
dest.fill('\0');
source.copy(dest.data(), count = 4); // pos = 0
std::cout << dest.data() << '\n'; // ABCD
dest.fill('\0');
source.copy(dest.data(), count = 4, pos = 1);
std::cout << dest.data() << '\n'; // BCDE
dest.fill('\0');
source.copy(dest.data(), count = 42, pos = 2); // ok, count -> 4
std::cout << dest.data() << '\n'; // CDEF
try
{
source.copy(dest.data(), count = 1, pos = 666); // throws: pos > size()
}
catch (std::out_of_range const& ex)
{
std::cout << ex.what() << '\n';
}
}