---
title: Introduction to Timers
framework: cocoa
role: article
path: apple-archive/documentation/Cocoa/Conceptual/Timers
---

# Introduction to Timers

Explains how to use timers for scheduling automatic, repeating message invocations in Cocoa.

## At a Glance

Timers work in conjunction with `NSRunLoop` objects. As a result, they don’t provide a real-time mechanism—their accuracy is limited.

For more about timers in general, see [Timers](Articles/timerConcepts.html#//apple_ref/doc/uid/20000806-BAJFBAIH) .

There are several aspects to using a timer. When you create a timer, you must configure it so that it knows what message to send to what object when it fires. You must then associate it with a run loop so that it will fire—some of the creation methods do this for you automatically. Finally, if you create a repeating timer, you must invalidate it when you want it to stop firing.

To learn more about using timers, see [Using Timers](Articles/usingTimers.html#//apple_ref/doc/uid/20000807-CJBJCBDE) .

[Next](Articles/timerConcepts.html)

Copyright © 2009 Apple Inc. All Rights Reserved. [Terms of Use](http://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](http://www.apple.com/privacy/) | Updated: 2009-07-14