From:	CSBVAX::CSBVAX::MRGATE::"SMTP::CRVAX.SRI.COM::RELAY-INFO-VAX" 23-MAR-1989 00:53
To:	MRGATE::"ARISIA::EVERHART"
Subj:	Re: Using $DCLEXH from Pascal


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Date:     Wed, 22 Mar 89 20:41 PDT
From:     <WILKINSO%UCLACH.BITNET@CUNYVM.CUNY.EDU>
Subject:  Re: Using $DCLEXH from Pascal
To:       INFO-VAX@KL.SRI.COM
X-Original-To:  INFO-VAX@KL.SRI.COM, WILKINSON

Before I answer a question, can anyone explain how to post to the entire
list? When I send to INFO-VAX@KL.SRI.COM, I never see whatever I send again
(and I assume other BITNETers don't either). When I send to INFO-VAX@MARIST,
the BITNET sites receive the posting, but the rest of the world doesn't.
What am I missing? Anyhow...

Marc Schenk (MSCHENK@CLSUNI51.BITNET) asks:

     I am trying to write PASCAL program which includes an exit handler.

     Would anyone be kind enough to send me a small example including ...

      ... the sys$dclexh function declaration
      ... the declaration of the procedure implementing the exit handler
      ... the exit_handler_block declaration and initialization
      ... the call to sys$dclexh

What follows shows enough to get you going. It isn't completely general with
respect to parameter passing, but will probably do for most instances.

(**)
Program Whatever; (* Declaring an exit handler in VAX Pascal *)

Type  Descriptor_Block = Record
        Forward_Link : [Pos (0)] Unsigned;
        Exit_Handler_Address : [Pos (32)] Unsigned;
        Argument_Count : [Pos (64)] Unsigned_Byte;
        Condition_Address : [Pos (96)] ^Unsigned;
       End;

Var   Exit_Descriptor : [Static] Descriptor_Block;


(* The Exit Handler *)

[Asynchronous, Unbound]
Function Game_Over (Condition : Unsigned) : Unsigned;

Begin
  .
  .
  .
End;

(* The Exit Handler *)


Begin (*MAIN*)
  .
  .
  .
  (* Declare Exit Handler *)
  Exit_Descriptor := Zero;
  Exit_Descriptor.Exit_Handler_Address := IAddress (Game_Over);
  New (Exit_Descriptor.Condition_Address);
  Stat := $DCLEXH (DesBlk := Exit_Descriptor);
  If Not Odd (Stat) Then $EXIT (Stat);
  .
  .
  .
End. (*MAIN*)
(**)

;+
James Wilkinson                            Phone: 1-213-206-5104
Department of Chemistry and Biochemistry
University of California, Los Angeles     BITNET: WILKINSON@UCLACH
405 Hilgard Avenue                      Internet: WILKINSON@UCLACH.CHEM.UCLA.EDU
Los Angeles, California  90024-1569  HEPnet/SPAN: ABBY::JAMES or 5882::JAMES
;-