multitables.py 文件源码

def __init__(self, size):
        # The size of the queue is increased by one to give space for a QueueClosed signal.
        size += 1
        import multiprocessing.sharedctypes
        # The condition variable is used to both lock access to the internal resources and signal new items are ready.
        self.cvar = multiprocessing.Condition()
        # A shared array is used to store items in the queue
        sary = multiprocessing.sharedctypes.RawArray('b', 8*size)
        self.vals = np.frombuffer(sary, dtype=np.int64, count=size)
        self.vals[:] = -1
        # tail is the next item to be read from the queue
        self.tail = multiprocessing.sharedctypes.RawValue('l', 0)
        # size is the current number of items in the queue. head = tail + size
        self.size = multiprocessing.sharedctypes.RawValue('l', 0)