[squeak-dev] RE: [Pharo-project] [FFI] ExternalStructure ownership
(or not) of memory
bschwab at anest.ufl.edu
Sat Apr 3 11:50:37 UTC 2010
Humor aside, it is an important consideration for a system that is to be able to run for any length of time. So far, I appear to be having good results in that area (yup, my servers are still running), but I am working on something that could turn into a real resource hog if it does not clean up after itself. I *think* the cleanup is limited to other wrapper objects, and the structs are largely just a convenience for accessing memory allocated elsewhere - I think ~:0
From: pharo-project-bounces at lists.gforge.inria.fr [mailto:pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of Andreas Raab
Sent: Saturday, April 03, 2010 12:33 AM
To: The general-purpose Squeak developers list; Pharo Development
Subject: Re: [Pharo-project] [FFI] ExternalStructure ownership (or not) of memory
On 4/2/2010 8:37 PM, Schwab,Wilhelm K wrote:
> So ExternalStructure>>free is not invoked by default? Sady to say, I never even considered that possibility.
It's not. Memory is cheap :-)
> -----Original Message-----
> pharo-project-bounces-bM+ny+RY8h+a+bCvCPl5/gCzwTLBPCX0 at public.gmane.or
> [mailto:pharo-project-bounces-bM+ny+RY8h+a+bCvCPl5/gCzwTLBPCX0 at public.
> gmane.org] On Behalf Of Andreas Raab
> Sent: Friday, April 02, 2010 8:24 PM
> To: The general-purpose Squeak developers list
> Cc: Pharo-project-bM+ny+RY8h+a+bCvCPl5/gCzwTLBPCX0 at public.gmane.org
> Subject: Re: [Pharo-project] [FFI] ExternalStructure ownership (or
> not) of memory
> I would suggest that you only register a finalizer for objects where
> *do* have responsibility to reclaim them. There are no implicit finalizers registered for any subclasses of ExternalObject by default - the only thing that happens is that all handles are cleared when the image is restarted.
> - Andreas
> On 4/2/2010 5:17 PM, Schwab,Wilhelm K wrote:
>> Hello all,
>> Suppose I have a pointer to a structure and I do or do not have the responsibility of reclaiming the memory when a corresponding ExternalStructure sub-instance is finalized. How do I distinguish the two cases? One idea I had is to explicitly set the handle to nil if I do not own the memory, but (please correct me if I'm wrong), I can't do that while I'm still using the instance because it will presumably use the handle in accessing the fields, right?
>> Looking at implementors of #isExternalAddress, maybe the idea is to use a byte array to make a copy of memory and an address to refer to it.
>> What should I be asking? :)
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