iOS Programming: The Big Nerd Ranch Guide

For the More Curious: The main Function and UIApplication

A C application begins by executing a main function. An Objective-C application is no different, but we haven’t seen main in any of our iOS applications. Let’s take a look now.

Open main.m in the HypnoTime project navigator. It looks like this:

i​n​t​ ​m​a​i​n​(​i​n​t​ ​a​r​g​c​,​ ​c​h​a​r​ ​*​a​r​g​v​[​]​)​
{​
 ​ ​ ​ ​@​a​u​t​o​r​e​l​e​a​s​e​p​o​o​l​ ​{​
 ​ ​ ​ ​ ​ ​ ​ ​r​e​t​u​r​n​ ​U​I​A​p​p​l​i​c​a​t​i​o​n​M​a​i​n​(​a​r​g​c​,​ ​a​r​g​v​,​
 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​n​i​l​,​ ​N​S​S​t​r​i​n​g​F​r​o​m​C​l​a​s​s​(​[​H​y​p​n​o​A​p​p​D​e​l​e​g​a​t​e​ ​c​l​a​s​s​]​)​)​;​
 ​ ​ ​ ​}​
}​

The function UIApplicationMain creates an instance of a class called ...