Method PushBack

include/Eigen/Eigen/src/ThreadPool/RunQueue.h:86–99

PushBack adds w at the end of the queue. If queue is full returns w, otherwise returns default-constructed Work.

  // PushBack adds w at the end of the queue.
  // If queue is full returns w, otherwise returns default-constructed Work.
  Work PushBack(Work w) {
    EIGEN_MUTEX_LOCK lock(mutex_);
    unsigned back = back_.load(std::memory_order_relaxed);
    Elem* e = &array_[(back - 1) & kMask];
    uint8_t s = e->state.load(std::memory_order_relaxed);
    if (s != kEmpty ||
        !e->state.compare_exchange_strong(s, kBusy, std::memory_order_acquire))
      return w;
    back = ((back - 1) & kMask2) | (back & ~kMask2);
    back_.store(back, std::memory_order_relaxed);
    e->w = std::move(w);
    e->state.store(kReady, std::memory_order_release);
    return Work();
  }

  // PopBack removes and returns the last elements in the queue.
  Work PopBack() {