On Feb 15, 2008, at 8:27 AM, Adam P Jenkins wrote:
I still don't understand. Why does it matter that the release
message to a NSAutoreleasePool would be a noop when running in GC
mode? Isn't autorelease also a noop? In which case the whole
NSAutoreleasePool is just a noop, since nothing would ever actually
get added to it. So I still don't understand the need for the drain
method as it's currently defined. Why couldn't you just send
release to the pool in both GC and non-GC apps? I'm not saying
what you said is wrong, I'm sure it's me that's missing something.
Thanks,
Local autorelease pools are typically an optimization that we use when
we know that we're going to generate a whole lot of temporary objects
in a very short period of time, to keep the over all footprint of the
application down. This improves the performance of your application,
but also of the system as a whole.
The same type of problem exists in GC apps of course, and while the
collector might - and in a perfect world should - be smart enough to
notice that you're generating temporary objects very quickly and to
determine that it needs to respond to that, it might also be that it
could benefit from a hint from the developer about this in much the
same way, and in the same type of situations, as where you would use a
local autorelease pool in non-GC.
There is API for providing such a hint in a GC app (-
[NSGarbageCollector collectIfNeeded]), but in code that runs in both
GC and non-GC it might be convenient to not have to use both types of
syntax and I think that's why "-drain" was introduced.
j o a r
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