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Re: Question Regarding the Memory Address of Objects
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Re: Question Regarding the Memory Address of Objects


  • Subject: Re: Question Regarding the Memory Address of Objects
  • From: "Clark S. Cox III" <email@hidden>
  • Date: Sat, 20 Dec 2008 07:00:02 -0500

The objective-c garbage collector does not move objects, so that is not an issue with using raw pointers.

Sent from my iPhone

On Dec 20, 2008, at 6:50, "Dong Feng" <email@hidden> wrote:

I have a concern that the direct use of a pointer as a memory address
may have a problem in the case of GC. In Java, object reference is not
a simple memory address because objects may be moved by GC. Does Cocoa
has a GC implementation avoid it?



2008/12/19 Carter R. Harrison <email@hidden>:

On Dec 18, 2008, at 3:44 PM, David Duncan wrote:

On Dec 18, 2008, at 11:57 AM, Carter R. Harrison wrote:

[dict setValue:@"button1" forKey:[NSString stringWithFormat:@"%x",
&button1]]; // "button1" is one of my IBOutlets.
NSString *value = [dict valueForKey:[NSString
stringWithFormat:@"%x", &sender]];


It seems like the memory address of the sender is different than what it
should be. I did some debugging and the address of the sender is always
bfffe2e8 which really shouldn't be possible at all.


Your confusing the pointer with the object itself. button1 is a pointer to
a button. sender is a pointer to the object that sent the message. When you
take the address of either pointer, you get the location of that pointer in
memory - not the location of the object. The pointer itself contains the
location of the object in memory.
--
David Duncan
Apple DTS Animation and Printing



David,

Once again you have saved me from pulling my hair out. Thank you once again
for your assistance. For the rest of the folks on the thread the solution
was to remove the "&" from the front of all my pointers.


Regards,
Carter
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  • Follow-Ups:
    • Re: Question Regarding the Memory Address of Objects
      • From: "Michael Ash" <email@hidden>
References: 
 >Question Regarding the Memory Address of Objects (From: "Carter R. Harrison" <email@hidden>)
 >Re: Question Regarding the Memory Address of Objects (From: David Duncan <email@hidden>)
 >Re: Question Regarding the Memory Address of Objects (From: "Carter R. Harrison" <email@hidden>)
 >Re: Question Regarding the Memory Address of Objects (From: "Dong Feng" <email@hidden>)

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