Re: In-loop releasing of objects does not free memory?

FROM : j o a r
DATE : Tue Feb 12 23:20:46 2008

On Feb 12, 2008, at 2:10 PM, Arthur C. wrote:

> I am writing a Cocoa-program to reduce a large amount of measurement 
> data.
> This involves reading in large files, like 6 MB each, in a loop over 
> about 60 of them.
> I try to release as many temporary objects as possible whenever I'm 
> finished with them. However, the memory is not freed, as can be seen 
> using Activity monitor, and by a dramatic slowdown due to memory 
> overflow.
>
> So the question is, how can I get the memory back? I need it for the 
> next file(s)...
>
> Code looks like this:
>
> NSArray * files; // contains a list of filenames
> for(i=0;i<[files count]; i++)
> {
>  NSString * dataFromFile = [[NSString alloc] initWithContentsOfFile: 
> [files objectAtIndex: i]];
>  < some processing >
>  [dataFromFile release];
> }
>
> Autoreleased instances behave the same, i.e. no memory gets really 
> freed.




Two suggestions:

* Use Instruments to figure out exactly what type of objects that 
you're "leaking" in your loop

* Try inserting a local autorelease pool in the loop. You might be 
using some API that creates autoreleased objects.

j o a r