#17650: alarm broken on cygwin
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Reporter: gouezel | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.5
Component: porting: Cygwin | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Changes (by gouezel):
* upstream: Reported upstream. No feedback yet. => N/A
Old description:
> On cygwin64, the alarm mechanism is broken:
> {{{
> sage: alarm(0.1); sum(xrange(100000000))
> 4999999950000000
> }}}
> instead of the expected interrupt.
>
> This seems to be a subtle cygwin and/or ppl bug: the included header
> ppl.hh contains lines akin to
> {{{
> class Parma_Polyhedra_Library::Init {
> public:
> Init();
> ~Init();
> ...
> }
> static Parma_Polyhedra_Library::Init Parma_Polyhedra_Library_initializer;
> }}}
>
> The methods `Init()` and `~Init()` are never defined in the header, so
> there are undefined references in the ppl library. This confuses
> cython(?), breaking `alarm`.
>
> Replacing the above lines with
> {{{
> Init() {};
> ~Init() {};
> }}}
> solves the alarm issue.
New description:
On cygwin64, the alarm mechanism is broken:
{{{
sage: alarm(0.1); sum(xrange(100000000))
4999999950000000
}}}
instead of the expected interrupt.
I traced the bug to ppl by dichotomy, but what is going on is very
mysterious to me. Here are my observations.
The included header ppl.hh contains lines akin to
{{{
class Parma_Polyhedra_Library::Init {
public:
Init();
~Init();
...
}
static Parma_Polyhedra_Library::Init Parma_Polyhedra_Library_initializer;
}}}
the class' methods are defined in the ppl library. Hence, the ppl module
makes calls to these methods. If one removes these calls, either by
commenting the line
{{{
static Parma_Polyhedra_Library::Init Parma_Polyhedra_Library_initializer;
}}}
or by replacing the above lines with
{{{
Init() {};
~Init() {};
}}}
then the alarm issue disappears (but `ppl` is not functional any more, of
course)
--
--
Ticket URL: <http://trac.sagemath.org/ticket/17650#comment:4>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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