gistfile1.m

dispatch_group_t group = dispatch_group_create();

dispatch_group_async(group, dispatch_get_main_queue(), ^{
	double delayInSeconds = 2.0;
	dispatch_time_t firstTaskPopTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
	dispatch_after(firstTaskPopTime, dispatch_get_main_queue(), ^(void) {
		NSLog(@"Task 1 complete");
	});
});

dispatch_group_async(group, dispatch_get_main_queue(), ^{
	double delayInSeconds = 1.0;
	dispatch_time_t secondTaskPopTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
	dispatch_after(secondTaskPopTime, dispatch_get_main_queue(), ^(void) {
		NSLog(@"Task 2 complete");
	});
});



dispatch_group_notify(group, dispatch_get_main_queue(), ^{
	NSLog(@"All tasks complete");
});