Re: 0x3ff00000 is what, exactly?
Re: 0x3ff00000 is what, exactly?
- Subject: Re: 0x3ff00000 is what, exactly?
- From: Glen Simmons <email@hidden>
- Date: Thu, 20 Nov 2003 15:57:30 -0600
On Nov 20, 2003, at 2:46 PM, David W. Halliday wrote:
email@hidden wrote:
So, I have this program that creates about 1000 instances of one
class. Every now and then it just crashes mysteriously, and debugging
shows it to be attempting to send a message to a non-existent object
(EXC_BAD_ACCESS).
However, this object exists, as given by the same behavior if I
include an
if (obj == nil) return;
before calling the particular method that crashes (always the same
one, a method that accesses the NSString that represents the path).
However, while it is not always the same object it crashes on (these
objects represent paths, among other things) the object is always at
address 0x3ff00000. Does this address have some significance? The
debugger shows all the instance vars to be 'invalid', as though there
isn't really an object there, or something.
Any thoughts? Is this some kind of out-of-memory error? Is there a
limit to the number of objects you can instantiate? The number of
NSStrings?
I'll try to make a simple test program to isolate the problem, if I
can.
Thanks,
J.D.
I have no /real/ idea why the address is "always" the same, I'm
certain that just because the pointer to the object is not nil (your
"obj == nil" test) guarantees nothing about the validity of an object
at the address in question. The trouble is that if the object is no
longer valid, then you cannot tell just by looking at the value of the
pointer that used to point to the object in question (other than to
devise a test on whether there is an actual, valid object there).
I recommend that you check your retain/release/auto-release chain.
All it takes, to have a non-nil object pointer to no longer /be/ a
pointer to a valid object, is to have the object in question freed
before your call.
The NSZombie stuff is of great help with this. See NSDebug.h.
HTH,
Glen
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