Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!ames!eos!shelby!portia!Jessica!duggie
From: duggie@Jessica.stanford.edu (Doug Felt)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Stale Pointers
Keywords: Lightspeed C
Message-ID: <3232@portia.Stanford.EDU>
Date: 29 Jun 89 02:48:47 GMT
References: <2394@ur-cc.UUCP> <27101@coherent.com>
Sender: USENET News System <news@Portia.stanford.edu>
Reply-To: duggie@Jessica.UUCP (Doug Felt)
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Others have pointed out that C does not specify the order of
evaluation in an assignment; I just thought I'd mention the related
gotcha that calls of functions in other segments can cause memory
compaction as well.  Especially since one may change the segmentation
scheme in the process of tuning a program, it's a good idea to never
use dereferenced handles in function calls, either as parameters or to
get the function result, without locking them (or using temporaries).

(This problem shows up often in Object Pascal as well, where the
notational convenience of being able to use 'object.foo' instead of
'object^^.foo' leads one to forget that dereferencing is taking place.
Of course, with Pascal you aren't supposed to know...)

Doug Felt
Courseware Authoring Tools Project
duggie@jessica.stanford.edu