Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cica!gatech!hubcap!billwolf%hazel.cs.clemson.edu
From: billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe, 2847 )
Newsgroups: comp.sw.components
Subject: Re: Moving things in and out of containers
Message-ID: <6494@hubcap.clemson.edu>
Date: 18 Sep 89 17:51:25 GMT
References: <6176@pt.cs.cmu.edu>
Sender: news@hubcap.clemson.edu
Reply-To: billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu
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>The classic approach would be to copy-in and copy-out the contents
>of such containers, but simply passing pointers to contents is
>often much faster.

   There are two approaches:

     1) Call it a container of objects.  In this case, the semantics
        are to store a copy, and the programmer may well rely on this,
        perhaps destroying or modifying the original while relying on
        the container to keep the earlier version handy.

     2) Call it a container of pointers.  In this case, the semantics
        are to store a pointer, and the programmer must refrain from
        destroying the original.  

   What we should NOT do is allege that we have a container of objects
   when in reality we have a container of pointers; the two are very
   different concepts with respect to the effects of object modification. 
  
   
   Bill Wolfe, wtwolfe@hubcap.clemson.edu