void store_lines_from_robotstxt_and_output_them(const std::string &host)
{
std::string robotstxt = get_robotstxt(host);
std::istringstream is(robotstxt);
std::string s;
while (std::getline(is, s))
{
auto p = lines.synchronize();
p->emplace_back(s);
}
// wait() blocks until the required number of threads has called wait();
// wait() returns true for only one thread
if (barrier.wait())
{
// value() provides unsynchronized access (no synchronization required
// as only one thread iterates over and outputs the lines)
for (auto &line : lines.value())
std::cout << line << '\n';
}
}
