Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!uflorida!stat!fsu!loligo!schrader
From: schrader@loligo (David F. Schrader)
Newsgroups: comp.lang.pascal
Subject: Re: exiting some calling ancestor in Turbo Pascal 5
Summary: Possible solution?
Keywords: ExitProc TP5.0/TP5.5 Exit_Procedure(s) Chaining_Exits
Message-ID: <412@fsu.scri.fsu.edu>
Date: 19 Dec 89 14:08:06 GMT
References: <122@crucible.UUCP> <8912141752.aa23459@ICS.UCI.EDU> <1989Dec18.132328.6049@murdoch.acc.Virginia.EDU>
Sender: news@fsu.scri.fsu.edu
Reply-To: schrader@loligo.UUCP (David F. Schrader)
Organization: Florida State University Computing Center
Lines: 53

In article <1989Dec18.132328.6049@murdoch.acc.Virginia.EDU> scl@sasha.acc.Virginia.EDU (Steve Losen) writes:
>
>In article <8912141752.aa23459@ICS.UCI.EDU> milne@ICS.UCI.EDU (Alastair
>Milne) writes
>
>  [description of need for multi-level "EXIT" deleted....]
>
>>   Turbo Pascal gives only, as far as I know, EXIT (which exits the immediate
>>   block, but nothing further) and HALT (which kills the whole program).
>>   Does anybody know of a way in Turbo Pascal to obtain the effect of UCSD
>
>  [followup note deleted...]
  
I am not sure that I have followed the entire thread of this sequence but I
believe that what you want to do is possible (at TP5.0/TP5.5 levels at
least). I do not know whether this is supported before TP5.n .
  
Check TP5.0 (and by extension TP5.5) Reference Guide Chapter 15, page 229,
regarding _Exit Procedures_. TP5.0 supports an _ExitProc_ pointer which points
to a procedure (w/o parameters) which is to be executed upon exit from a
program (and program "unit"). By saving, replacing, and later restoring, the
pointer it is possible to "chain" these _Exit Procedure_s. The _Exit Procedure_
must be compiled in _Far_ call model ({$F+}/{$F-}). The brief example that
provide is: 
  
PROGRAM Testexit;
  
VAR
  ExitSave : pointer;
  
{$F+}
PROCEDURE MyExit;
BEGIN
  ExitProc := ExitSave;
  : 
END; {MyExit}
{$F-)
BEGIN {Main/Testexit}
  ExitSave := ExitProc;
  ExitProc := @MyExit;
  : 
END. {Main/Testexit}
  
Note that the manuals is much more expansive in their coverage. Please read
this(these) page(s) before committing yourself to this particular method as
I cannot guarentee this is the solution you are seeking (particularly since
I am coming in in the middle of the thread...).
  
Hope that this helps.
  
David F. Schrader
Disclaimer : FSUCC - "No comment." ; ME - "I reserve the right to qualify
                                           what I said if necessary."