From: Robert Klemme <bob.news@...>
Date: 2004-01-15T18:21:37+09:00
Subject: Re: Stack level too deep (SystemStackError)


"Gennady" <gfb@tonesoft.com> schrieb im Newsbeitrag
news:292FAB16-4733-11D8-95BE-0003939AEA24@tonesoft.com...
>
> On Jan 14, 2004, at 23:31, Jesper Olsen wrote:
>
> > Gennady <gfb@tonesoft.com> wrote in message
> > news:<4005BB60.70009@tonesoft.com>...
> >> Jesper Olsen wrote:
> >>> I have a program where I'm getting a Stack level too deep
> >>> (SystemStackError)
> >>> exception
> >>>
> >>> I did not expect this, and I would prefer to fix it by increasing
the
> >>> stack, rather than changing the program...
> >>>
> >>> Is this possible?
> >>> I think this exception is quite common, but was not able to google a
> >>> solution.
> >>>
> >>> Jesper
> >>>
> >>> --
> >>> http://JesperOlsen.Net
> >>>
> >> What's your OS? BTW, it is a known issue with Mac OS X where in most
> >> cases you must increase the default stack size.
> >
> > How?
>
> In bash, "ulimit -s" shows the current stack size in kbytes (defaults
> to 8192 in Mac OS X, really low). To change it issue "ulimit -s
> <kbytes>".
>
> The command may be different for other shells. You may put this command
> in /etc/profile to be set every time a user logs in.
>
> >
> >>
> >> Gennady.
> >
> > It happens both with
> >
> > - Ruby 1.6.8 on BSD Unix
> > - Ruby 1.8.0 on Win2000
>
> The above command will work for BSD Unix too. I do not know how to do
> it for Win2000.
>
> Are you sure that there's no actual problem with your program? It may
> really be run-away in recursion, so increasing the stack size will only
> make the problem happen somewhat later.

Hm.  On cygwin this happens:

10:15:30 [ContentReporter_BRANCH]: cat /c/temp/ruby/ulimit.sh
#!/bin/bash -f

ruby -e 'def t(i);p i;t(i+1);end;t(0)'
ulimit -s


<lines deleted>
13281
13282
13283
-e:1:in `p': stack level too deep (SystemStackError)
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
         ... 13274 levels...
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1
2047

This means that a stack size of approx 2MB suffices only for 13000+ stack
levels.  IOW about 157 bytes per stack frame.

Unfortunately this can't be changed on cygwin:

10:16:06 [ContentReporter_BRANCH]: ulimit -s 4096
bash: ulimit: stack size: cannot modify limit: Invalid argument
10:18:19 [ContentReporter_BRANCH]: ulimit -S -s 4096
bash: ulimit: stack size: cannot modify limit: Invalid argument
10:18:23 [ContentReporter_BRANCH]: ulimit -H -s 4096
bash: ulimit: stack size: cannot modify limit: Invalid argument

I've always felt that Ruby is not too comfortable with recursion...

Cheers

    robert