Grand Central Dispatch is one of the truly great APIs to come out of Apple in the past few years. In the latest installment of the Let's Build series, I'm going to explore a reimplementation of the most basic features of dispatch_queue, a topic suggested by Rob Rix.

Reader Paul Kim pointed out an entry on Michael Tsai's blog about making dispatch_once fast. While the comment in the dispatch_once source code is fascinating and informative, it doesn't quite delve into the detail that some would like to see. Since this is one of my favorite hacks, for today's article I'm going to discuss exactly what's going on there and how it all works.

Dispatch groups are a handy facility for synchronizing multiple tasks, and an anonymous reader suggested them for the subject of today's Let's Build.

Happy iPhone Day to all! For those of you stuck waiting in line or waiting for the delivery guy, never fear, for I have the solution to your pain. For today's topic, Jon Shier suggested that I talk about the new features in Grand Central Dispatch in Lion and iOS 5.

Happy April Fool's Day to all my readers, and welcome to one web site which won't irritate you all day with bizarre practical jokes. Instead, I bring you another edition of Friday Q&A. In this edition, I will discuss various ways of handling signals in Mac programs, a topic suggested by friend of the blog Landon Fuller.

Welcome back to another Friday Q&A. This week I'm departing from my usual user-driven format to present a class I've written for what I'm calling "background timers", and discuss potential uses for it.

Alexander Babaev has been kind enough to translate my series of posts on blocks and GCD into Russian for TouchDev.ru. So far he has posted two, Blocks in Objective-C and Intro to Grand Central Dispatch, Part I. Others in the series will be going up in the future. If you happen to speak Russian, check them out!

It's time for another wintry edition of Friday Q&A. From the comfort of your toasty-warm homes, you can read about building an HTTP server using Grand Central Dispatch, a topic suggested by Steven Degutis.

Welcome back to another Friday Q&A. I'm off to C4 today (hope to see you there!) but I've prepared this in advance so everyone stuck at home (or worse, work) can at least have something interesting to read. Over the past four weeks I've introduced Grand Central Dispatch and discussed the various facilities it provides. In Part I I talked about the basics of GCD and how to use dispatch queues. In Part II I discussed how to use GCD to extract more performance from multi-core machines. In Part III I discussed GCD's event dispatching mechanism, and in Part IV I took care of various odds and ends that I hadn't covered before. This week I'm going to examine a practical application of using GCD to speed up the production of thumbnails for a large quantity of images, a topic suggested by Willie Abrams.

It's that time of the week again. Over the past three weeks I've introduced you to the major pieces Grand Central Dispatch, an exciting new API for parallel processing and event handling in Snow Leopard. The first week I covered basic concepts and dispatch queues. The second week I discussed how to use dispatch queues for parallel processing on multi-core computers. The third week I covered GCD's event handling system. This week I'm going to cover various odds and ends which I didn't get to before: dispatch queue suspension and targeting, semaphores, and one-time initialization.

There's a lot of discussion going around the internet lately about blocks and Grand Central Dispatch. They're both great new technologies that have seen the light of day with the 10.6 release, and they see a lot of use together. However, a lot of the people discussing blocks and GCD don't seem to understand that they are not, in fact, the same thing, and aren't even really related. I just wanted to make a quick note here to describe exactly what each one is, how they're different, and how they work together.

Welcome back to another Friday Q&A. This week I continue the discussion of Grand Central Dispatch from the past two weeks. In the last two weeks I mainly focused on dispatch queues. This week I'm going to examine dispatch sources, how they work, and how to use them.

Welcome back to Friday Q&A. Last week I discussed the basics of Grand Central Dispatch, an exciting new technology in Snow Leopard. This week I'm going to dive deeper into GCD and look at how you can use GCD to take advantage of multi-core processors to speed up computation. This post assumes that you've read last week's edition, so be sure to do that if you haven't already.

Welcome back to Friday Q&A. This week's edition lines up with Apple's release of Snow Leopard, so I'm going to take this opportunity to open up the discussion on previously NDA'd technologies and talk about some of the cool stuff now available in Snow Leopard. For this week I'm going to start what I plan to be an ongoing series on Grand Central Dispatch, a topic suggested by Chris Liscio.

As you saw from my last post, I was sorely disappointed in this year's WWDC keynote. Fortunately the rest of the week didn't follow the same trend.