- (void)doComplicatedStuffWithCoreData {
    [self.managedObjectContent lock];
     ON_SCOPE_EXIT(^{
         // Unlock the context no matter how we return from method
         [self.managedObjectContext unlock];
     });
	 
     // do complicated stuff with many return points
	 // ...
}

- (void)allocateMemoryAndDoStuff {
    char *buffer = (char *)malloc(sizeof(int) * 1000);
    
    ON_SCOPE_EXIT(^{
		// Make sure buffer is always freed
        free(buffer);
    });
	
	// do complicated stuff with buffer
	// ...
}

- (void)useCoreFoundation {
    CFMutableAttributedStringRef attrString = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
	
    MAKE_GUARD(^{
		// Make sure attributed string is always released
		CFRelease(attrString);
	});
	
	// use attributed string
	// ...
}