#6391: libGAP! -- create a Cython library interface to gap
----------------------------------------------------------------------------+
Reporter: was |
Owner: was
Type: enhancement |
Status: needs_review
Priority: major |
Milestone: sage-5.3
Component: group theory |
Resolution:
Keywords: |
Work issues:
Report Upstream: N/A |
Reviewers: Dima Pasechnik, Ivan Andrus, Volker Braun, William Stein
Authors: Dima Pasechnik, Ivan Andrus, Volker Braun, William Stein |
Merged in:
Dependencies: #13211 |
Stopgaps:
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Comment (by dimpase):
Replying to [comment:113 vbraun]:
> Your changes look fine. The `test/main.c` example doesn't do proper
error handling, so you shouldn't expect a useful error message. For a
relevant stack backtrace you need to post what happens before you get into
the error loop.
Well, I rebuilt libgap with SAGE_DEBUG on, and I can see it starting the
interpreter interaction, parsing the input, calling gasman, then something
goes wrong, it tries to print the message {{{"Variable: 'FreeGroup' must
have a value"}}}
{{{
(gdb)
libGAP_SPrTo (buffer=0x7fffffffd0d0 "Variable: 'FreeGroup' must have a
value", maxlen=120,
format=0x7ffff7750098 "Variable: '%s' must have a value",
arg1=140733014557528, arg2=0)
at scanner.c:3049
}}}
then I see
{{{
(gdb)
libGAP_SyStrncat (dst=0x7fffffffcd20 "justQuit", src=0x7ffff775e32c
"justQuit", len=1023)
at system.c:682
(gdb)
libGAP_RNamName (name=0x7ffff775e32c "justQuit") at records.c:110
}}}
and it tries to go further. Eventually I see
{{{
(gdb)
libGAP_ErrorQuit (msg=0x7ffff77472a0 "Variable: <<unknown>> must have an
assigned value", arg1=0,
arg2=0) at gap.c:1451
(gdb)
libGAP_CallErrorInner (msg=0x7ffff77472a0 "Variable: <<unknown>> must have
an assigned value",
arg1=0, arg2=0, justQuit=1, mayReturnVoid=0, mayReturnObj=0,
lateMessage=0x7ffef510a678,
printThisStatement=1) at gap.c:1430
}}}
this gets repeated many times (buffer corruption), and eventually a
segfault.
{{{
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff75a8eef in libGAP_RNamName (name=Cannot access memory at
address 0x7fffff7fefa8
) at records.c:79
}}}
the trouble starts of course much earlier, before it fails to recognize
{{{FreeGroup}}} as a valid GAP function...
.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/6391#comment:115>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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