Date:         Tue, 2 Jan 2001 18:08:43 +0100
Reply-To:     Peter Crawford <peter.crawford@DB.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Peter Crawford <peter.crawford@DB.COM>
Subject:      Re: Deleting macro variables from memory
Content-type: text/plain; charset=iso-8859-1

If your macro variables are not, and cannot be, %local, as recommended by "maven fehd" below,
then you could use this routine to reduce the memory they use.
(May I suggest for "safe" programming, that only the "owner" or
"creator" of a variable should be allowed to delete it.
for example ... create and delete at the same code level..
  .. unless well justified and explained )
The idea behind this routine, is to take the sas system meta data
dictionary table of macro variable names, subset suitably and
generate code like
   %let &mvarname =;
for each macro varname

 proc sql noprint;
      select   trim(name)
        into :MVARS separated by '=; %let '
        from dictionary.macros
       where scope ne 'AUTOMATIC' and
              /*  whatever criteria is applicable for your set of macro vars,  and*/
             name ne 'MVARS' ;
      %put INFO: found &sqlobs macro vars ;
 quit;
 option symbolgen;
%let  &mvars =;
Using up to 16 chars per macro var, this method should be good
enough for circa. 2000 varco vars and more if average name length
is less than 8

Just be careful not to empty macro vars you might still need !

Good luck


Datum:         02/01/2001 16:00
An:            SAS-L@listserv.uga.edu




Antwort an:    rjf2@cdc.gov

Betreff:       Re: Deleting macro variables from memory,              when a program is runni ng.
Nachrichtentext:


> From: Aldi Kraja [mailto:     aldi@wubios.wustl.edu]

> If I create a large group of macro variables such as:
> %do i=1 %to &nrOfMacV;
> ma&i=&i;
> %end;
>
> where &nrOfMacV=400.
>
> How can I delete these macro variables from the temporary
> memory, after
> I am done with them, and in mean time the program will continue with
> other steps.

if you are using a %do loop within a macro and you know the limit
which you name NrOfMacV;
then you should declare your set of macro variable %local before the
assignment statements:

> %do i=1 %to &nrOfMacV;
> %local ma&i;
> %let ma&i=&i;
> %end;

Ron Fehd  the macro maven  CDC Atlanta GA USA RJF2@cdc.gov
OpSys: WinNT   Ver: 8.1
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-- Ashleigh Brilliant





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