Re: blocks and autorelease weirdness
Re: blocks and autorelease weirdness
- Subject: Re: blocks and autorelease weirdness
- From: Julien Jalon <email@hidden>
- Date: Mon, 19 Apr 2010 12:39:33 +0200
And of course, I need some rest:
On Mon, Apr 19, 2010 at 12:38 PM, Julien Jalon <email@hidden> wrote:
> I have to add that *you can't assume* using dispatch_async on main queue
> within an NSApp will automatically drain the autorelease pool.
>
> AppKit drains the autorelease pool upon NSEvents dispatch.
>
>
> On Mon, Apr 19, 2010 at 12:36 PM, Julien Jalon <email@hidden> wrote:
>
>> I don't see anything wrong with the output being 1/2:
>>
>> -(void) test
>> {
>> testString = NULL;
>>
>> dispatch_async(dispatch_get_global_queue(0, 0), ^{
>> dispatch_async(dispatch_get_main_queue(), ^{
>>
>> NSString* aString = [[NSMutableString alloc] init];
>> * // retain count is 1*
>>
>> NSLog(@"retainCount: %d",[aString retainCount]);
>>
>> testString = [aString retain]; *// retain count is
>> 2*
>>
>> [aString *auto*release]; *// retain count is still
>> 2 - object will be released sometimes in the future*
>>
>>
>> dispatch_async(dispatch_get_main_queue(), ^{
>> NSLog(@"retainCount: %d",[testString
>> retainCount]);* // you can't assume the future release has already been
>> called*
>> });
>> });
>> });
>> }
>>
>> On Mon, Apr 19, 2010 at 11:35 AM, Henk Kampman <
>> email@hidden> wrote:
>>
>>> Have a look at the following code
>>>
>>> -(void) test
>>> {
>>> testString = NULL;
>>>
>>> dispatch_async(dispatch_get_global_queue(0, 0), ^{
>>> dispatch_async(dispatch_get_main_queue(), ^{
>>>
>>> NSString* aString = [[NSMutableString alloc]
>>> init];
>>> NSLog(@"retainCount: %d",[aString retainCount]);
>>>
>>> testString = [aString retain];
>>>
>>> [aString release];
>>>
>>> dispatch_async(dispatch_get_main_queue(), ^{
>>> NSLog(@"retainCount: %d",[testString
>>> retainCount]);
>>> });
>>> });
>>> });
>>> }
>>>
>>> As expected the output is:
>>>
>>> retainCount: 1
>>> retainCount: 1
>>>
>>> However when I change [aString release] to [aString autorelease] the
>>> output shows:
>>>
>>> retainCount: 1
>>> retainCount: 2
>>>
>>> Why?
>>>
>>> BTW I first noticed this behavior when my application started leaking the
>>> QTMovie objects I was creating in a block.
>>>
>>> -
>>>
>>> Henk_______________________________________________
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>>
>>
>
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