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Re: How to free the memory occupied by the instance object?
- To: firstname.lastname@example.org
- Subject: Re: How to free the memory occupied by the instance object?
- From: email@example.com (Richard Lynch)
- Date: 26 Jul 1994 00:45:53 GMT
- Distribution: world
- Newsgroups: comp.lang.lisp.mcl
- Organization: ILS
- References: <firstname.lastname@example.org>
In article <email@example.com>, Yao-Sheng Cheng
| I am working to build a multimedia authoring system using MCL&CLOS.
|I have a problem that how to release the memory of objects created
|through make-instance. Does the MCL garbage collector is so clever to
|collect these memory back or I must explicitly call some functions to
|free these memory?
Sorry folks. Tried e-mail twice, but it bounced.
As has been noted, MCL is that clever [actually any Common LISP
implementation is required to be that clever], *BUT* there is one gotcha
with MCL and garbage collection that has not yet been noted.
If you have created mac pointers [machine specific data structures], and
have stored them in slots, you need to be sure to dispose of them when
they are no longer needed.
For example, a window has a wptr slot that contains a WindowPtr [?] record
that can be passed to MacOS ToolBox trap calls (#_xxx (wptr <window>)).
When a window is closed, its wptr is disposed.
The upshot is, pointers and handles are NEVER disposed automatically; you
must take care of them yourself if you create them.
All the MCL builtin code, and [almost for sure] all the user-contributed
code do this properly, but it's up to you to do it properly for your own
mac pointers such as PICT, SND , etc handles.
I'm not sure exactly where to point you for good examples of mac pointer
management; perhaps somebody else would care to suggest one of the
user-contributed documents for this.
-- "TANSTAAFL" Rich firstname.lastname@example.org