Python in a Nutshell, 2nd Edition

The threading Module

The threading module is built on top of module thread and supplies multithreading functionality in a more usable, higher-level form. The general approach of threading is similar to that of Java, but locks and conditions are modeled as separate objects (in Java, such functionality is part of every object), and threads cannot be directly controlled from the outside (which means there are no priorities, groups, destruction, or stopping). All methods of objects supplied by threading are atomic.

threading provides numerous classes for dealing with threads, including Thread, Condition, Event, RLock, and Semaphore. Besides factory functions for the classes detailed in the following sections, threading supplies the currentThread factory function.

currentThread

currentThread( ) Returns a Thread object for the calling thread. If the calling thread was not created by module threading, currentThread creates and returns a semi-dummy Thread object with limited functionality.

Thread Objects

A Thread object t models a thread. You can pass t’s main function as an argument when you create t, or you can subclass Thread and override the run method (you may also override _ _init_ _ but should not override other methods). t is not ready to run when you create it; to make t ready (active), call t.start( ). Once t is active, it terminates when its main function ends, either normally or by propagating an exception. A Thread t can be a daemon, meaning that Python can terminate even if t