D I S P A T C H A W E S O M E 

Hi, I’m Sam @soffes 

Grand Central Dispatch libdispatch 

Open Source libdispatch.macosforge.org 

What’s here? 

dispatch_async dispatch_sync 

dispatch_async(dispatch_get_main_queue(), ^{ NSLog(@"Hello world"); }); 

dispatch_after dispatch_time 

dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, 2.0 * NSEC_PER_SEC); dispatch_after(time, dispatch_get_main_queue(), ^{ NSLog(@"The future"); }); 

dispatch_once 

static NSArray *stuff = nil; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ ! stuff = @[@"NSMeetup", @"SF"]; }); 

dispatch_apply 

dispatch_apply(10, queue, ^(size_t i) { ! NSLog(@"Iteration: %ld", i); }); 

dispatch_group 

dispatch_queue_t queue = dispatch_get_main_queue(); dispatch_group_t group = dispatch_group_create(); dispatch_group_async(group, queue, ^{ ! NSLog(@"Hello"); }); dispatch_group_async(group, queue, ^{ ! NSLog(@"World"); }); dispatch_group_notify(group, queue, ^{ ! NSLog(@"Done!"); }); dispatch_release(group); 

dispatch_semaphore 

dispatch_semaphore_t s = dispatch_semaphore_create(0); dispatch_semaphore_signal(s); dispatch_async(backgroundQueue, ^{ ! dispatch_semaphore_wait(s, DISPATCH_TIME_FOREVER); ! dispatch_async(dispatch_get_main_queue(), ^{ NSLog(@"Animation is done!"); ! }); }); [UIView animateWithDuration:0.3 animations:block completion:^(BOOL finished) { // ... dispatch_semaphore_signal(s); }]; 

dispatch_suspend dispatch_resume 

dispatch_suspend(queue); dispatch_resume(queue); 

dispatch_*_f 

dispatch_barrier_* 

dispatch_io 

dispatch_set_target_queue 

dispatch_source dispatch_data 

Patterns 

Main Background Main 

Serial Queue 

Thanks