empty()

[cdemez]

Hi,

I just wrote the "empty" method, just want to share it. I hope it is correct (it is based on the try_pop)

bool empty() noexcept { auto tail = tail_.load(std::memory_order_acquire); for (;;) { auto &slot = slots_[idx(tail)]; if (turn(tail) * 2 + 1 == slot.turn.load(std::memory_order_acquire)) { if (tail_.compare_exchange_strong(tail, tail + 1)) { return false; } } else { auto const prevTail = tail; tail = tail_.load(std::memory_order_acquire); if (tail == prevTail) { return true; } } } }