Simplest possible event notification system in Cocoa

Notify.m

#import <Foundation/Foundation.h>

int main (int argc, const char *argv[]) {
	NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

	[[NSNotificationCenter defaultCenter]
		addObserverForName:@"randomEvent" object:nil
		queue:[NSOperationQueue mainQueue]
		usingBlock:^(NSNotification *note) {
			NSString *message = [[note userInfo] valueForKey:@"message"];

			NSLog(@"Received message = %@", message);
		}
	];
	
	NSDictionary *dict = [[NSDictionary alloc]
		initWithObjectsAndKeys: @"Hello, world!", @"message",
		nil
	];

	[[NSNotificationCenter defaultCenter]
		postNotificationName:@"randomEvent" object:nil userInfo:
	];
	
	[pool drain];
	
	return 0;
}

/*

// You could also setup an observer using an instance method instead of a
// block, like this:

[[NSNotificationCenter defaultCenter]
	addObserver:self selector:@selector(handleNotification:)
	name:@"randomEvent" object:nil userInfo:nil
];

*/