Re: What happens when I call NSMakeCollectable on a CFArrayRef?
Re: What happens when I call NSMakeCollectable on a CFArrayRef?
- Subject: Re: What happens when I call NSMakeCollectable on a CFArrayRef?
- From: Andrew Thompson <email@hidden>
- Date: Sun, 20 Jan 2008 12:42:16 -0500
On Jan 19, 2008, at 6:17 PM, Clark Cox wrote:
On Jan 19, 2008 2:56 PM, Andrew Thompson <email@hidden> wrote:
I want to call a Core function that returns a CFArrayRef and make the
result garbage collectable.
The CFArray contains CFStrings...
Is this pattern OK?
-(NSArray *) doFoo {
return NSMakeCollectable(CFCopyFoo(someArgs));
}
Where CFCopyFoo returns a new CFArray containing copied CFStrings.
This will make the array collectable, but will do nothing to the items
contained therein; the contents are still reference counted. However,
this is most likely what you want anyway (Just as in pre-GC code, when
an item is removed from the array, or the array itself is
collected/deallocated, the item will have its reference count
decremented, and will be deallocated if that was the last remaining
reference).
That's more or less what I figured, thanks.
Or do I have to iterate over the array and call NSMakeCollectable on
each item in it?
That would do something completely different, and would not be a good
idea (it would be akin to calling CFRelease on each of the items).
Really? I would have thought that since each is in the array, so long
as the array isn't garbage then each string is referenced and is
therefore also not garbage and will stick around as long as the array
does?
So on balance - if the strings are going to be left in the array, then
making the array collectable is enough - once it becomes garbage the
strings will be released too.
Conversely if I intend to pull the strings out of the array and start
passing them around to other objects in my program, I likely want to
take the extra trouble to make each one collectable, otherwise I might
forget to release them and they'll leak.
AndyT (lordpixel - the cat who walks through walls)
A little bigger on the inside
(see you later space cowboy, you can't take the sky from me)
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