Mike Ash has been offline for a while, but his Friday Q&A is back with a detailed line-by-line analysis of the objc_msgsend function on ARM64. This is the core Objective-C runtime function that sends

That’s been my opinion of auto-layout too … in theory it should be awesome, but configuring it is ridiculously complex. Every iteration of IB seems to make some of the process easier, but adds more be

Great. Where’s that good guide? Xcode’s own documentation is so sparse as to be useless. The 3rd party books I’ve seen are massive doorstops aimed at newbies that spend 990 pages on the basics of Coco

“Why, I wouldn’t become a Mason now if you went down on your lousy stinking knees and begged me!” —John Cleese, “The Architect Sketch” No seriously, I hadn’t heard of this before, but it looks very pr

Changing the target name changes the product name and module name (by default unless you explicitly specify them.) The references to your Swift classes in IB still have the old module name in them. Yo

You can implement a property observer instead. Here’s an example from the Swift book: class StepCounter { var totalSteps: Int = 0 { willSet(newTotalSteps) { print("About to set totalSteps to \(newTota

Yup, I would recommend using CALayers for the whole UI, pretty much. Back when Core Animation first came out I wrote a framework for building board/card games: https://bitbucket.org/snej/geekgameboard

It’s been years since I did much with CoreAnimation, but IIRC a layer is clipped to its parent layer, so if you want this to happen you need to make the view temporarily be a direct subview of your Ro

Have you made sure the “release on close” checkbox isn’t set in IB? (But do you really want the prefs controller to hang around when it’s closed? Seems like a waste of memory to me.) —Jens

I think you resolve this by changing it to the form shown in the error messages, i.e. - (BOOL)isNiceAndHas: (NSArray *__autoreleasing *)friends; —Jens

The call you showed runs the block on the main thread. That aspect may be crucial. Does the code this is part of run on a different thread/queue? Also, it can often be very useful to defer some code u

LaunchDaemons is the wrong directory; that’s for system daemons that run outside of any user context. (I’m surprised you actually got this to work, because it’s difficult to present any UI from a daem

For some reason lost in ancient Unix history, if you write to a file-descriptor that’s been closed at the other end, a SIGPIPE signal is raised. This will by default kill your process. It’s annoying b

It does seem absurd that the most fundamental APIs — the C standard library and POSIX/Darwin system calls — aren’t supported by Xcode’s documentation features. Especially since the header files give z

If it did, it would break most apps, so no. —Jens

It wouldn’t be a valid filesystem if it didn’t support the system calls like stat() that NSFileManager uses to get file attributes. Now, not every filesystem supports every attribute (you’re not going

Right. You need to keep track of that yourself, like with a Peer class that can hold onto those streams and act as their delegate. NSNetService doesn't really have anything to do with those streams. A

You can't assign (or compare) arrays in C/C++. You have two options: (a) Call memcpy: memcpy(&myArray, &_mArray, sizeof(myArray)); (b) Wrap a struct around the array, since structs are copyable. Drawb

This is a classic newbie networking mistake. (No offense I hope!) TCP is a stream, and there is absolutely no delimiter between writes, and no association between the number of bytes written vs. the n

(IIRC you suggested using an NSMutableArray of NSNumbers?) Honestly, it depends. It does have overhead, although not as much as it used to, since NSNumbers of reasonable-size integers don't allocate a