NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/sys/amiga/programmer/2080

Internet Message Format | 1996-08-05 | 1.8 KB

Path: doc.ic.ac.uk!not-for-mail
From: [e-mail] (Martin Frost)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: More linked list nonsense
Date: 26 Jan 1996 15:29:59 -0000
Organization: Dept. of Computing, Imperial College, University of London, UK.
Distribution: world
Message-ID: <4eas1n$[e-mail]>
References: <4e5nih$[e-mail]>
Reply-To: [e-mail] (Martin Frost)
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In article <4e5nih$[e-mail]>, Jeff Grimmett <[e-mail]> writes:
>It just occurred to me last night, as I pored over steaming code, that
>the function Remove() (used to remove nodes from linked lists) might
>POSSIBLY not be freeing the memory allocated to the node it is removing.
>Does anyone have some insight on this?  It's difficult to deallocate a
>node once it's not part of the list, but it's pretty STUPID to free it
>BEFORE. :-)

Remove() is a low-level list manipulation function. To see what it does, look
at the macro REMOVE in the assembly file "exec/lists.i".

It frees no memory, does no list arbitration, and makes no assumptions about
anything other than that the first 8 bytes of the specified node are a
MinimalListNode structure (ie pointer to next, pointer to previous). Since
standard ListNodes simply have additional data tacked on the end, this works
for all such nodes. You are responsible for freeing any memory associated with
the node (or indeed you may not want to, for example if the node is embedded
as preinitialised data in your program's code).

I don't know if the exec.library function returns a pointer to the node or
not: I don't have the Autodocs with me right now. Even if it doesn't, it isn't
really *too* much effort to cache the node pointer in a variable while calling
the function :-)

Martin