Sender: david AT killerlabs DOT com
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Date: Fri, 20 Aug 1999 19:24:10 -0700
From: David Ford <david AT kalifornia DOT com>
Organization: Talon Technology, Intl.
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To: pgcc AT delorie DOT com
CC: Oliver Jennrich <oliver DOT jennrich AT colorado DOT edu>
Subject: Re: Something hogs memory...
References: <Pine DOT SOL DOT 3 DOT 96 DOT 990820133808 DOT 4247D-100000 AT ursa DOT cus DOT cam DOT ac DOT uk>
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Reply-To: pgcc AT delorie DOT com

Just a note, in the below, you would certainly get a segfault if you
attempted to free the assignment later.

-d

"Dr H. T. Leung" wrote:

> That reminds me of a curious thing with egcs-compiled curl 5.0/5.2 binary
> sigmentation-faulting with an assignment like this
>
> > config.useragent= "curl/" CURL_VERSION " (" OS CURL_SSL")";
>
> and the problem was fixed by
>
> > config.useragent= strdup("curl/" CURL_VERSION " (" OS CURL_SSL")");
>
> While gcc 2.7.x was perfectly happy with the former. I think your problem
> was probably related. See the curl mailing list archive for entries under
> my name in December 1998 towards the top in:
>
> http://curl.haxx.nu/archive-pre_5_10/
>
> On 19 Aug 1999, Oliver Jennrich wrote:
>
> >
> > Hi folks,
> >
> > first of all, I'm not on the list, so any 'cc:' to me would be greatly
> > appreciated.
> >
> > I think I discovered a bug, although I'm not sure that it is *really*
> > a pgcc bug, but then, gcc.486 does not show this behaviour.
> >
> > It is kind of complicated because it involves NAG's Fortran95 (no it
> > is *not* their bug). The string concatenation hogs memory. This is
> > easily demonstrated by the following code:
> >
> > Program MEMTEST
> >   !
> >   !  Shows a memory leak when compiled with NAG f95 compiler.
> >   !
> >   use f90_unix_env
> >   use f90_unix_proc
> >   !
> >   character                :: command*32, text,dummy*32
> >   integer                  :: pid
> >   !
> >   open(8,file='/dev/null')
> >   pid=getpid()                       ! get process ID
> >   write(command,'(i10)') pid
> >   command='ps vp '//command
> >   do n=1,100
> >      write(8,*) 'sample ',n
> >      do i=1,10000
> >         text=' '
> >         text=trim(text)//' abc'      ! HOG
> >         write(8,'(a)') text
> >      end do
> >      if (n == 1) call system(command) ! memory after first inner loop
> >   end do
> >   call system(command)               ! memory after last inner loop
> >   !
> > end program memtest
> >
> > Depending on the existence of the line marked 'HOG' the program
> > allocates huge amounts of mem.
> >
> > With HOG:
> >   PID TTY STAT TIME  PAGEIN TSIZ DSIZ  RSS   LIM %MEM COMMAND
> > 29144  ?  S    0:00     155   32 1343  536    xx  0.4 ./memtest
> >   PID TTY STAT TIME  PAGEIN TSIZ DSIZ  RSS   LIM %MEM COMMAND
> > 29144  ?  S    0:04     155   32 5211 4404    xx  3.4 ./memtest
> >
> > Without HOG:
> >   PID TTY STAT TIME  PAGEIN TSIZ DSIZ  RSS   LIM %MEM COMMAND
> > 29155  ?  S    0:00     123   31 1304  492    xx  0.3 ./memtest
> >   PID TTY STAT TIME  PAGEIN TSIZ DSIZ  RSS   LIM %MEM COMMAND
> > 29155  ?  S    0:02     123   31 1304  492    xx  0.3 ./memtest
> >
> > You might argue that this is not a bug at all, but then, using the
> > gcc.486 as the C-Compiler NAG_f95 uses, it becomes:
> >
> >   PID TTY STAT TIME  PAGEIN TSIZ DSIZ  RSS   LIM %MEM COMMAND
> > 29166  ?  S    0:00     126   31 1304  504    xx  0.3 ./memtest
> >   PID TTY STAT TIME  PAGEIN TSIZ DSIZ  RSS   LIM %MEM COMMAND
> > 29166  ?  S    0:04     126   31 1304  504    xx  0.3 ./memtest
> >
> > with and without the HOG-line.
> >
> > For those of you not familiar with Fortran-syntax: '//' concatenates
> > strings, much as strcat() does.
> >
> > The compilers in question are:
> > gcc version pgcc-2.91.66 19990314 (egcs-1.1.2 release)
> > and
> > gcc version 2.7.2.3
> >
> > If it is of any help I can provide anyone with the preprocessed
> > .i-Files andør the preprocessed C files, f95 produces.
> >
> >
> >
> > --
> > Oliver Jennrich               JILA, University of Colorado @ Boulder
> >
> > Gravity. It's not just a good idea, it's the law!
> >
>
>           --------------------------------------------------
> "What you don't care cannot hurt you."            Chap. 7a, AMS-NS

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