7.7 Queue -- A synchronized queue class
Keywords: lib

# 7.7 `Queue` -- A synchronized queue class

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()` (or `get_nowait()`) is called on a `Queue` object which is empty or locked.

`Full`
  Exception raised when non-blocking `put()` (or `put_nowait()`) is called on a `Queue` object which is full or locked.

Subsections

- 7.7.1 Queue Objects