#10818: EclLib should allow signals to make LISP code interruptable
--------------------------+-------------------------------------------------
Reporter: nbruin | Owner: was
Type: defect | Status: needs_review
Priority: major | Milestone: sage-4.7
Component: interfaces | Keywords: lisp ecl signal interrupt
Author: Nils Bruin | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
--------------------------+-------------------------------------------------
Changes (by nbruin):
* status: needs_work => needs_review
* work_issues: investigate ECL interrupt handling =>
* milestone: sage-feature => sage-4.7
Comment:
Apply handlerswap.p2.patch
Another take on swapping handlers and this one seems to work:
{{{
sage: from sage.interfaces.maxima_lib import maxima as max
sage: max('sum(1/x^2, x, 1, 100000)')
^C---------------------------------------------------------------------------
[...]
TypeError: ECL says: Console interrupt
sage: #we press Ctrl-C again
KeyboardInterrupt
}}}
For reference, ECL prefers to use sigaction (in fact, probably sage should
be using sigaction as well. Certain race conditions with signal are
avoidable with sigaction). In glibc, signal is implemented via sigaction
anyway. sigaction has a richer interface, so signal cannot always properly
report what sigaction has done. By using sigaction to record and swap the
different SIGINT handlers, it seems to work.
Subtle race conditions still exist: the ECL handler is instated just
before entering lisp code and setting up the "unwind-protect stack frame",
so an interrupt that gets delivered in that window would cause unspecified
behaviour. By running
while True: os.kill(<PID>,2)
it is easy to trigger such behaviour, but sage in its present state
already cannot handle this.
Therefore, I think the present patch establishes acceptable "best effort"
behaviour.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10818#comment:4>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
