Xcode debugger (lldb) get object description from memory address

Little-known fact: It is now possible, in Xcode, while paused in the debugger, to introspect the notification center to learn what objects are registered to receive what notifications:

(lldb) po NotificationCenter.default

<NSNotificationCenter:0x6040000d40b0>
Name, Object, Observer, Options
com.apple.accessibility.reduce.motion.status, 0x10b126190, 0x7fc795700140, 1001
com.apple.accessibility.asst.scanner.status, 0x10b126190, 0x7fc795700140, 1001
// ... etc. ...

Very nice, but how do I get from the memory address 0x7fc795700140 to learning what object that is?

  • “return” from method while stepping?
  • Is there any way to breakpoint all the button touchUpInside method?
  • NSNotificationCenter addObserver in Swift
  • lldb fails to print variable values with “error: reference to 'id' is ambiguous”
  • Xcode LLDB watchpoints
  • Rapid row insertion into UITableView causes NSInternalInconsistencyException
  • 2 Solutions Collect From Internet About “Xcode debugger (lldb) get object description from memory address”

    po works for addresses (In Objective-C/Mac context, at least)

    e.g.:

    (lldb) po [NSNotificationCenter defaultCenter]

    NSWindowDidResizeNotification, 0x7fff9a0e98e0, 0x6100001246a0, 1400

    (lldb) po 0x6100001246a0

    ExpandOneView: 0x6100001246a0

    The Swift equivalent of Phillip’s answer is:

    (lldb) expr -l objc -O -- 0x7fc795700140
    <UIApplication: 0x7fc795700140>