Sanket sanketfirodiya

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.
Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

Not for everyone. Each programmer has their own appreciation of what is good coding music.

For when I need to think deep, debug something, or design

(From most influential to least)

David Helpling & Jon Jenkins (sample)
Patrick O'Hearn (sample)
Ólafur Arnalds (sample)
Michael Hedges (sample)
Alex de Grassi (sample)

This document has moved!

It's now here, in The Programmer's Compendium. The content is the same as before, but being part of the compendium means that it's actively maintained.

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

	// Do you often find yourself writing lines of code that look like this?
	// let viewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("ViewController") as! ViewController
	// Here's a simpler way, using generics and Swift type-casting (as long as the viewcontroller's storyboard identifier is its class name).
	// Now you can write: let viewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController() as ViewController

	extension UIStoryboard {
	func instantiateViewController<T: UIViewController>() -> T {
	guard let vc = instantiateViewControllerWithIdentifier(String(T)) as? T else {
	fatalError("Could not locate viewcontroller with with identifier \(String(T)) in storyboard.")
	}

	<?php

	// Put your device token here (without spaces):
	$deviceToken = 'DEVICE_TOKEN';

	// Put your private key's passphrase here:
	$passphrase = 'passphrase';
	$pemfilename = 'ck.pem';

	// SIMPLE PUSH