Beefy Boxes and Bandwidth Generously Provided by pair Networks
Your skill will accomplish
what the force of many cannot
 
PerlMonks  

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
I'm trying to find out the common cases where dead-on timely destruction of objects is necessary, such that the lack of timely destruction would alter the semantics of the program badly enough to break it.

I ran into cases where delayed destruction caused problem while working on database drivers for Smalltalk years ago. There may be a parallel to Perl. These drivers were the equivalent of DBD. Instances of drivers would hold external references to stuff in the native database libraries. If one dropped a reference to a database statement, ideally what would happen is that a destructor method would make the necessary call to the native database library to free the statement. (We were using "weak reference" under the covers to make this work.) But ParcPlace Smalltalk would only destroy objects after a garbage collection sweep, which could be deferred in time. We ended up having to manually trigger GCs at points to force "finalization" of database driver objects.

The parallel that might hold for Perl is where an object "holds" an reference to an object in an external system (e.g., a database statement handle), and where having the external object "open" is semantically different from having it closed/freed. If script drops all references to the Perl-side object representing a statement handle, but the invocation of DESTROY is delayed, the external system (the native database library) could be left in an undesirable state.


In reply to Re: On timely destruction? by dws
in thread On timely destruction? by Elian

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others having an uproarious good time at the Monastery: (7)
As of 2024-03-28 09:31 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found