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Re: [Visualpython-users] Problems with exception handling in vpython on Linux
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From: Guenter S. <Gue...@ph...> - 2009-09-01 03:53:01
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See below.
Robert Xiao wrote:
>
>
> ---------- Forwarded message ----------
> From: *Robert Xiao* <nne...@gm... <mailto:nne...@gm...>>
> Date: 2009/8/31
> Subject: Re: [Visualpython-users] Problems with exception handling in
> vpython on Linux
> To: Guenter Schneider <Gue...@ph...
> <mailto:Gue...@ph...>>
>
>
> 2009/8/31 Guenter Schneider <Gue...@ph...
> <mailto:Gue...@ph...>>
>
> I ran into a number of problems with vpython on Linux which appear to be
> all related. The problems do not happen in Windows. My system is ubuntu
> 9.04, vpython 5.12 compiled from source (5.11 gives identical results).
>
>
> What version of the Boost libraries are you using?
boost 1.35 (libboost1.35-dev)
>
>
> Thee common feature I see on Linux is, whenever vpython raises an
> exception, python seg. faults.
>
> Example 1:
>
> In [1]: from visual import *
>
> In [2]: a = vector(1,2,3)
>
> In [3]: for i in a:
> ...: print i
> ...:
> ...:
> 1.0
> 2.0
> 3.0
> Segmentation fault
> ~ $
>
> but the following works:
>
> Example 2:
>
> In [1]: from visual import *
>
> In [2]: a = vector(1,2,3)
>
> In [3]: for i in a:
> ...: print i
> ...: if i>2:
> ...: break
> ...:
> ...:
> 1.0
> 2.0
> 3.0
>
> This seems to point to the raising a StopIteration exception as the
> problem point.
>
>
> Example 3:
> In [1]: from visual import *
>
> In [2]: a = [1,2,3]
>
> In [3]: mag2(a)
> Out[3]: 14.0
>
> In [4]: a = [1,2,'x']
>
> In [5]: mag2(a)
> Segmentation fault
> ~ $
>
>
> It should have raised a TypeError as in this case
>
> It's actually Boost.Python.ArgumentError, since [1,2,'x'] can't be
> coerced to a vector, so it is passed in as a list.
I was guessing and did not try everything on Windows.
>
> >>> visual.mag2([1,2,'x'])
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> Boost.Python.ArgumentError: Python argument types in
> visual.cvisual.mag2(list)
> did not match C++ signature:
> mag2(class cvisual::vector)
> mag2(class boost::python::numeric::array)
>
>
> Finally this fails as well:
>
> Example 5:
> In [1]: from visual import *
>
> In [2]: quit()
> Do you really want to exit ([y]/n)?
> Segmentation fault
> ~ $
>
> quit() is a Python built-in, and it isn't overridden by Visual. Does
> quit() work if you don't import visual?
Yes.
>
> Can you try these tests:
> vector(1,2,3)[4] # throws std::out_of_range
> vector('x')
> faces(pos=[1])
> faces(normal=[])
>
> These all directly throw exceptions.
>
All end in seg. faults on my system.
In [1]: from visual import *
In [2]: faces(normal=[])
Segmentation fault
I appreciate your help.
Guenter
>
>
> 2009/8/31 Bruce Sherwood <Bru...@nc...
> <mailto:Bru...@nc...>>
>
> Moreover, your Example 1 is exceptionally strange, as it should not
> give an
>
> error of any kind (nor does it give an error for me). Is it possible
> that
> there's a typo in your reporting of Example 1?
>
>
> StopIteration is raised by an iterator when it has no more objects to
> iterate over. It is not an error, but it can be raised by an iterator.
>
> Robert
>
>
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--
-----------------------------------------------------
Guenter Schneider
Email: Gue...@ph...
Phone: 541 737 1706
Fax: 541 737 1683
Oregon State University
Department of Physics
301 Weniger Hall
Corvallis, OR 97331-6507, USA
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