Re: those darn exceptions

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From	Gregory Ewing <greg.ewing@canterbury.ac.nz>
Newsgroups	comp.lang.python
Subject	Re: those darn exceptions
Date	Fri, 24 Jun 2011 19:50:34 +1200
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Chris Torek wrote:
> I can then check the now-valid
> pid via os.kill().  However, it turns out that one form of "trash"
> is a pid that does not fit within sys.maxint.  This was a surprise
> that turned up only in testing, and even then, only because I
> happened to try a ridiculously large value as one of my test cases.

It appears that this situation is not unique to os.kill(),
for example,

 >>> import os
 >>> os.read(999999999999999999999999, 42)
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
OverflowError: Python int too large to convert to C long

In fact I'd expect it to happen any time you pass a
very large int to something that's wrapping a C function.

You can't really blame the wrappers for this -- it's not
reasonable to expect all of them to catch out-of-range ints
and do whatever the underlying function would have done if
it were given an invalid argument.

I think the lesson to take from this is that you should
probably add OverflowError to the list of things to catch
whenever you're calling a function with input that's not
fully validated.

-- 
Greg

Thread

those darn exceptions Chris Torek <nospam@torek.net> - 2011-06-21 01:43 +0000
  Re: those darn exceptions Chris Angelico <rosuav@gmail.com> - 2011-06-21 13:19 +1000
    Re: those darn exceptions Chris Torek <nospam@torek.net> - 2011-06-21 04:40 +0000
  Re: those darn exceptions Ben Finney <ben+python@benfinney.id.au> - 2011-06-21 14:04 +1000
  Re: those darn exceptions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-21 09:49 +0000
    Re: those darn exceptions Chris Torek <nospam@torek.net> - 2011-06-21 21:51 +0000
      Re: those darn exceptions John Nagle <nagle@animats.com> - 2011-06-27 11:52 -0700
  Re: those darn exceptions Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-06-23 20:16 +1200
    Re: those darn exceptions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-23 18:40 +1000
    Re: those darn exceptions Chris Torek <nospam@torek.net> - 2011-06-23 18:33 +0000
      Re: those darn exceptions Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-06-24 19:50 +1200
        Re: those darn exceptions Chris Torek <nospam@torek.net> - 2011-06-24 18:21 +0000
          Re: those darn exceptions Ben Finney <ben+python@benfinney.id.au> - 2011-06-25 10:25 +1000
            Re: those darn exceptions Chris Angelico <rosuav@gmail.com> - 2011-06-25 13:55 +1000
              Re: those darn exceptions steve+comp.lang.python@pearwood.info - 2011-06-26 00:28 +1000
                Re: those darn exceptions Chris Angelico <rosuav@gmail.com> - 2011-06-26 01:52 +1000

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