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Path: utzoo!watmath!wateng!pdbain
From: pdbain@wateng.UUCP (Peter Bain)
Newsgroups: net.lang.pascal
Subject: Re: Comparing pointers in Pascal
Message-ID: <1946@wateng.UUCP>
Date: Thu, 31-Jan-85 16:22:32 EST
Article-I.D.: wateng.1946
Posted: Thu Jan 31 16:22:32 1985
Date-Received: Fri, 1-Feb-85 23:43:21 EST
References: <3161@ucla-cs.UUCP> <9300010@uiucdcsb.UUCP>
Reply-To: pdbain@wateng.UUCP (Peter Bain)
Organization: U of Waterloo, Ontario
Lines: 35
Summary: 

In article <9300010@uiucdcsb.UUCP> mcnabb@uiucdcsb.UUCP writes:
>It seems to me that the important point here is that Pascal objects to the
>use of the value of a pointer in any attempt to ascertain information about
>where the "pointee" lies in memory.  Pascal does not object to the use of
>an assumption that every unique pointer has a corresponding unique scalar
>value, which may be sorted, compared, etc. just like any integer.  Why not
>use "ord (your_pointer)" for the problem above?  Pascal permits the conversion
 ----------------------- (emphasis mine)
>of (unique?)* pointers into (unique?)* integers, but tries to prevent direct
>arithmetic on pointers because this is clearly implementation-dependent.
>BTW, ord (pointer) is a freebie (i.e. NOP) in most Pascal compilers.

I asked our local Pascal guru and he said:

From watmath!water!watbun!atbowler  Thu Jan 31 14:08:04 1985
From: watmath!water!watbun!atbowler
Message-Id: <8501311844.AA09296@water>
Date: Thu 31 Jan 1985 13:44
To: water!pdbain@wateng
Sent: Thu 31 Jan 1985 13:44
Status: RO

Re: ORD in Pascal
  ORD of a pointer is quite definitly not legal.  Some Pascal
supply a method of producing an integer from a pointer so that
you have a printable value.  In Pascal-8 this is the ADDR function.
This is an extension not part of the language.

	-peter
-- 
   - peter bain
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