std::filesystem::path::root_path

From cppreference.com
< cpplrm; | filesystemlrm; | path
path root_path() const;
(since C++17)

Returns the root path of the path. If the path does not include root path, returns path().

Effectively, returns the following: root_name() / root_directory()

Parameters

(none)

Return value

The root path of the path.

Exceptions

(none)

Example

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;

int main()
{
    std::cout << "Current root path is: " << fs::current_path().root_path() << '\n';
}

Possible output:

Current root path is: "C:\"

See also

returns the root-name of the path, if present
(public member function)
returns the root directory of the path, if present
(public member function)