Re: lldb 'print object' (po) prints pointer value if not object?

Subject: Re: lldb 'print object' (po) prints pointer value if not object?
From: Quincey Morris <email@hidden>
Date: Tue, 22 Apr 2014 22:47:30 -0700

On Apr 22, 2014, at 22:37 , Roland King <email@hidden> wrote:

So if that is a tagged pointer then some of those bits represent the fact it's tagged (the LSB) and what type it is (who knows how many others, possibly the next 3), so if it is an NSNumber representing an integer, the value is shifted up some number of bits, past the tag bits, so the value wouldn't be 83, it might be 5 (>>4), or zero (>>8), or something else.

You were correct, but I missed the significance of what you said until far too late. Sorry.

The tagged pointer for NSNumber 83 is 0x5327, I just found with test code. Based on 'http://www.opensource.apple.com/source/objc4/objc4-551.1/runtime/objc-internal.h', a pointer ending in 0x3 doesn’t seem to be a valid tagged pointer at all.

Greg Parker explained what the bits are, I think, a couple of months ago, but I can't remember where he said it.

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References:
	>lldb 'print object' (po) prints pointer value if not object? (From: Jerry Krinock <email@hidden>)
	>Re: lldb 'print object' (po) prints pointer value if not object? (From: Quincey Morris <email@hidden>)
	>Re: lldb 'print object' (po) prints pointer value if not object? (From: Roland King <email@hidden>)
	>Re: lldb 'print object' (po) prints pointer value if not object? (From: Quincey Morris <email@hidden>)
	>Re: lldb 'print object' (po) prints pointer value if not object? (From: Jerry Krinock <email@hidden>)
	>Re: lldb 'print object' (po) prints pointer value if not object? (From: Roland King <email@hidden>)

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