UIApplicationMain

UIApplicationMain

This function is called in the

main

entry point to create the application object and the application delegate and set up the event cycle.

int UIApplicationMain (
   int argc,
   char *argv[],
   NSString *principalClassName,
   NSString *delegateClassName
);

ParametersargcThe count of arguments in argv; this usually is the corresponding parameter to

main

.argvA variable list of arguments; this usually is the corresponding parameter to

main

.principalClassNameThe name of the

UIApplication

class or subclass. If you specify

nil

,

UIApplication

is assumed.delegateClassNameThe name of the class from which the application delegate is instantiated. If principalClassName designates a subclass of

UIApplication

, you may designate the subclass as the delegate; the subclass instance receives the application-delegate messages. Specify

nil

if you load the delegate object from your application’s main nib file.Return ValueEven though an integer return type is specified, this function never returns. When users exits an iOS application by pressing the Home button, the application moves to the background.DiscussionThis function instantiates the application object from the principal class and and instantiates the delegate (if any) from the given class and sets the delegate for the application. It also sets up the main event loop, including the application’s run loop, and begins processing events. If the application’s

Info.plist

file specifies a main nib file to be loaded, by including the

NSMainNibFile

key and a valid nib file name for the value, this function loads that nib file.Despite the declared return type, this function never returns.