hi, * Dave Angel <d...@davea.name> [2012-03-28 04:38]: > On 03/27/2012 06:27 PM, Michael Poeltl wrote: > >hi, > > > >can anybody tell why this 'little stupid *thing* of code' let's > >python-3.2.2, 2.6.X or python 2.7.2 segfault? > > > >>>def get_steps2(pos=0, steps=0): > >... if steps == 0: > >... pos = random.randint(-1,1) > >... if pos == 0: > >... return steps > >... steps += 2 > >... pos += random.randint(-1,1) > >... return get_steps2(pos,steps) > >... > ><SNIP> > >0 > >2 > >8 > >0 > >Segmentation fault > >?> > > > >funny, isn't it? > >I was able to reproduce this segfault on various machines (32bit 64bit), > >ubuntu, slackware, debian > >python.X segfaults on all of them > > > >thx > >Michael > > Others have explained why you can't just raise the recursion limit > to arbitrarily large values, and why there's no particular bound on > the possible recursion size. But the real question is why you don't > do the completely trivial conversion to a non-recursive equivalent. > > All you need do is add a while True: to the beginning of the > function, and remove the return statement. yeah - of course 'while True' was the first, most obvious best way... ;-) but I was asked if there was a way without 'while True' and so I started the 'recursive function'
and quick quick; RuntimeError-Exception -> not thinking much -> just adding two zeros to the default limit (quick and dirty) -> segfault ==> subject: python segfault ;-) and that was my first time that I received a segfault and not an Exception NOW it's quite clear ;-) thank you! Michael > > > > -- > > DaveA > -- Michael Poeltl Computational Materials Physics voice: +43-1-4277-51409 Univ. Wien, Sensengasse 8/12 fax: +43-1-4277-9514 (or 9513) A-1090 Wien, AUSTRIA cmp.mpi.univie.ac.at ------------------------------------------------------------------------------- ubuntu-11.10 | vim-7.3 | python-3.2.2 | mutt-1.5.21 | elinks-0.12 ------------------------------------------------------------------------------- -- http://mail.python.org/mailman/listinfo/python-list
