New subject: Memory leak in stringutils.pas?

9 Apr 2002

      OK, just speculating here ...   <G>
I'd think that "known problem with some string
operations (especially concatenation) in a loop"
means "writeln(os1+' '+os2+os3+os4+os5+os6)"
is the problem, since this is string concatenation
and is within a "while" loop ...
Joe.
...
-----Original Message-----
From:	Preben Mikael Bohn [SMTP:preben_bohn@yahoo.com]
Sent:	Tuesday, April 09, 2002 6:06 PM
To:	gpc@gnu.de
Subject:	Re: Memory leak in stringutils.pas?
I don't know if I understand you the right way (I probably don't).
I just tried to move tokenize+dispose into a subroutine (but still
in the loop) like the following, but it still has a memory leak...
program test1;
uses
  GPC,
  stringutils;
function split(
  var inStr                   : string;
  var os1,os2,os3,os4,os5,os6 : string;
  var c       : charset ) : integer;
var
   tokens : PPStrings;
begin
   tokens := TokenizeString (inStr, c);
   os1 := tokens^[1]^;
   os2 := tokens^[2]^;
   os3 := tokens^[3]^;
   os4 := tokens^[4]^;
   os5 := tokens^[5]^;
   os6 := tokens^[6]^;
   split := tokens^.count;
   DisposePPStrings (tokens);
end;
var
  line,os1,os2,os3,os4,os5,os6 : string;
  lineNumber, count : integer;
  c : charset;
begin
  c := ['¤'];
  lineNumber := 0;
  while lineNumber < 1000000 do
  begin
    line := 'string1¤string2¤string3¤string4¤string5¤string6';
    inc(lineNumber);
    count := split(line, os1,os2,os3,os4,os5,os6,c);
    if (linenumber mod 10) = 0 then
    begin
      writeln('Line number : ', lineNumber);
      writeln(os1+' '+os2+os3+os4+os5+os6);
    end;
  end;
end.
Best regards
Preben Bohn
--- Frank Heckenbach frank@g-n-u.de wrote: >
=?iso-8859-1?q?Preben=20Mikael=20Bohn?= wrote:
...
...
After sucessfully installing GPC I tried the following
(basically a
...
loop around the stringutils test-program). However it seems to
have
...
a memoryleak, after a while (~14%MEM on my machine) it comes
out
...
with a segmentation fault (and with top you can see that the
memory
...
usage grows)...
The memory leak is not in the unit, but in GPC itself. It's a
known
problem with some string operations (especially concatenation) in
a
loop. (If you can read /proc/n/maps, you'll see that it's the
stack,
not the heap that grows.) Moving the thing out of the loop
(syntactically, e.g. in a subroutine) is a work-around.
Frank
-- 
Frank Heckenbach, frank@g-n-u.de, http://fjf.gnu.de/, 7977168E
GPC To-Do list, latest features, fixed bugs:
http://www.gnu-pascal.de/todo.html
=====

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