Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!eos!ames!elroy!orion.cf.uci.edu!uci-ics!ics.uci.edu!milne
From: milne@ics.uci.edu (Alastair Milne)
Newsgroups: comp.lang.pascal
Subject: Re: function return value
Message-ID: <8910@paris.ics.uci.edu>
Date: 10 Mar 89 02:40:48 GMT
References: <18581@adm.BRL.MIL>
Sender: news@paris.ics.uci.edu
Reply-To: Alastair Milne <milne%ics.uci.edu@orion.cf.uci.edu>
Distribution: usa
Organization: Educational Technology Center, Dept. of ICS, UC Irvine
Lines: 35
To: MATHRICH@umcvmb.missouri.edu

MATHRICH@umcvmb.missouri.edu (Rich Winkel UMC Math Department) writes:
>function what(var where:string):string;
>begin
>   what:=where;
>   what:=what+what; (* string concatenation *)
>end;
>I'd actually like to reference the function return buffer (on the stack) 
> as a variable.
>I tried something like:
>var alias:string absolute what;
>in an attempt to reference the buffer, but TP 5 acts like it wants the 'what'
>to be an actual function call

     Turbo Pascal has never been very clever in its error diagnoses.  It seems
     to be a little better now than it was in versions 2 or 3, but not much.

     Referring to the actual address of the function (which you could do with
     ADDR( What) ) is most unlikely to get you anywhere -- it's bound to be 
     the address of the code in memory, and not of the function result.  In
     fact, Turbo used to use AX to hold the result, and the means of getting
     to that are a) probably more trouble than convenience, and it's
     convenience you're after, and b) unreliable, since you can't be sure
     what's using AX at the time you reference it.

     You mention the stack.  Are you sure TP5 uses the stack for function
     results?  There are Pascals that do, but I doubt if Turbo is among them.
     Previous versions have not.

     I have seen at least one Pascal with a function-like construct like 
     "VALUE(<funcname>)", which always returned the function's present value, 
     rather than assuming a recursive call.  As far as I know, though, this is
     not standard at all.


     Alastair Milne