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From: mikael@sm.luth.se (Mikael Eriksson)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: Two Questions (1 HyperTalk, 1 XCMD's)...
Message-ID: <225@my6.sm.luth.se>
Date: 22 Feb 89 08:26:10 GMT
References: <685@gould.doc.ic.ac.uk> <2600@spray.CalComp.COM>
Sender: mikael@sm.luth.se
Reply-To: Mikael Eriksson <mikael@my6.sm.luth.se>
Organization: University of Lulea, Sweden
Lines: 64
UUCP-Path: {uunet,mcvax}!enea!my6.sm.luth.se!mikael

In article <2600@spray.CalComp.COM> anson@spray.UUCP (Ed Anson) writes:
>In article <685@gould.doc.ic.ac.uk> np@doc.ic.ac.uk (Nigel Perry) writes:
>
>>(b) In XCMD/XFCN's is there an official/recommended way of storing globals
>>between calls to the XMCD?
>
>The OFFICIAL way to store globals is to convert the data to text and store
>it in a HyperCard global. HyperCard provides call-backs for the purpose.
>
>Personally, I don't like that idea, since it can be a major performance
>problem, not to mention a pain in the ...

Another approved way to do this is to have a Handle to the data.
(At least it was recommended by the Apple reps here in Sweden.)
To save it just convert the *Handle* to text (with NumToHex for example)
and save the text in a global. To retrieve the data do a StuffHex.

Example: (In TML Pascal)

  const
    globalName ='MyHCGlobal';
  var
    saveThis: Handle;
    globalString: Str255;
 (* Help routines *)
  procedure PasSetGlobal(paramPtr:XCMDPtr; name,value: Str255);
  (* Set global name to value *)
  var
    hndl: Handle;
  begin
    hndl:=PasToZero(paramPtr,value);
    SetGlobal(paramPtr,name,hndl);
    DisposHandle(hndl);
  end;

  function PasGetGlobal(paramPtr:XCMDPtr; name:Str255):Str255;
  (* Return the value of global name *)
  var
    hndl: Handle;
    str: Str255;
  begin
    hndl:=GetGlobal(paramPtr,name);
    ZeroToPas(paramPtr,hndl^,str);
    PasGetGlobal:=str;
    DisposHandle(hndl);
  end;

  (* To save the data *)
  PasSetGlobal(paramPtr,globalName,NumToHex(paramPtr,ORD(saveThis),8));

  (* To retreive the data *)
  globalString := PasGetGlobal(paramPtr,globalName);
  if length(globalString)=8 then
    begin
      StuffHex(@saveThis,globalString);
      ...
    end
  else
    error;
-- 
Mikael Eriksson (Email: mikael@sm.luth.se)
.........
You are in error. 2+2=5
Thank you for your cooperation. The Computer.