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Re: Using CFHash to tell if a CFTypeRef has changed?
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Re: Using CFHash to tell if a CFTypeRef has changed?


  • Subject: Re: Using CFHash to tell if a CFTypeRef has changed?
  • From: Jens Alfke <email@hidden>
  • Date: Mon, 11 Jan 2016 17:17:08 -0800

> On Jan 11, 2016, at 10:18 AM, Dave <email@hidden> wrote:
>
> Any one have any other techniques for telling if a CFTypeRef has changed?

No, in general there is no way. You’d have to make a copy of the object, keep that around, and then later call CFEqual on the current object and the copy … except that (a) there is no generic CFCopy function, and (b) if there were it would only make a shallow copy, so you wouldn’t be able to detect changes to nested objects (i.e. an item in a CFArray changing.)

What’s the bigger picture? What do you want to use this for?

—Jens
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References: 
 >Using CFHash to tell if a CFTypeRef has changed? (From: Dave <email@hidden>)
 >Re: Using CFHash to tell if a CFTypeRef has changed? (From: Jens Alfke <email@hidden>)
 >Re: Using CFHash to tell if a CFTypeRef has changed? (From: Jens Alfke <email@hidden>)
 >Re: Using CFHash to tell if a CFTypeRef has changed? (From: Dave <email@hidden>)

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