7.6 Standard Module Queue

The Queue module implements a multi-producer, multi-consumer FIFO queue. It is especially useful in threads programming when information must be exchanged safely between multiple threads. The Queue class in this module implements all the required locking semantics. It depends on the availability of thread support in Python.

The Queue module defines the following class and exception:

Queue (maxsize)

Constructor for the class. maxsize is an integer that sets the upperbound limit on the number of items that can be placed in the queue. Insertion will block once this size has been reached, until queue items are consumed. If maxsize is less than or equal to zero, the queue size is infinite.

Empty

Exception raised when non-blocking get (e.g. get_nowait()) is called on a Queue object which is empty, or for which the emptyiness cannot be determined (i.e. because the appropriate locks cannot be acquired).