std::vector<std::string> split(const std::string &str, std::string regex)
{
    std::regex r{ regex };
    std::sregex_token_iterator start{ str.begin(), str.end(), r, -1 }, end;
    return std::vector<std::string>(start, end);
}

split("Some  string\\t with whitespace ", "\\\\s+"); // "Some", "string", "with", "whitespace"