Daemon threads are threads that run in the background of a program and do not require explicit termination. This tutorial will delve into the topic of daemon threads in Python, providing a comprehensive overview of what they are and how they work. Readers will learn how to create and manage daemon threads, as well as understand their importance in various programming contexts. Whether you are a beginner or an experienced Python developer, this tutorial is a valuable resource for mastering the mechanics of daemon threads.

Table of Contents :

  • What are Daemon Threads in python
  • Creating a Daemon Thread in python
  • Daemon Threads vs. Non-Daemon Threads

What are Daemon Threads in python :

  • In Python, daemon threads are a type of thread that runs in the background
  • daemon threads are used to perform tasks that do not require a user's intervention.
  • A daemon thread automatically stops running when all other non-daemon threads have completed.
  • Daemon threads can be useful for performing background tasks, such as system monitoring, log file processing, and other similar tasks.

Creating a Daemon Thread in python :

  • In Python, you can create a daemon thread by setting the  daemon  attribute of the thread to  True  before starting it.
  • A daemon thread can also be created by subclassing the  threading.Thread  class and implementing the  run()  method as usual.
  • Code Sample :

import threading
import time

def daemon():
   while True:
       print("Daemon thread is running.")

# Creating a daemon thread using the setDaemon() method
d = threading.Thread(target=daemon)

# Wait for user input
input("Press any key to exit.\n")

Explanation :

  • Here, we create a daemon thread  using the  threading.Thread  class and 
  • the  daemon()  function as its target.
  • We then set the  daemon  attribute to  True  using the  setDaemon()  method and 
  • start the thread using the  start()  method.
  • The program waits for user input before terminating, allowing the daemon thread to continue running in the background.

Daemon Threads vs. Non-Daemon Threads :

  • When a Python program exits, all non-daemon threads are stopped, even if they are still running.
  • Daemon threads, on the other hand, are automatically stopped when the program exits, regardless of whether they have completed running or not.
  • Daemon threads can also be used to ensure that background tasks are terminated if the main program encounters an error or is otherwise terminated unexpectedly.

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