[GiNaC-devel] Crash during startup

[Richard B. Kreckel]

On Sat, 8 Jan 2005, Chris Dams wrote:
> On Fri, 7 Jan 2005, Richard B. Kreckel wrote:
>
> > Theoretically, by making sure the library_init ctor constructs it as well.
> > Maybe using placement new or some such trick.
>
> Yes, that might be made to work. I hadn't thought about placement new.

It's the same idea as std::ios_base::Init in the C++ standard [27.4.2.1.6].

> Another thing: I think it is wrong that count is a static int of
> library_init. This is given a value in utils.cpp, which may be after the
> point that library_init::library_init() does its work. Shouldn't it be a
> static of the constructor library_init::library_init()?

No, it's a POD integral type which comes pre-initialized by the
linker.  So making it a static member is okay.

>                                                         The destructor
> isn't doing much anyway.

That's true.  (And different from the standard library which
has to flush cout, clog, etc.)

> Here's a patch.

Your patch looks very interesting but something is wrong with it,
although I am unable to see what.  It does not fix the original
problem if I revert the patch in integral.cpp.  All the tests still
segfault.  Also, what's the point in self-assigning those pointers
where they should really just be declarations?  And then, the static
member variable initialization is actually okay, as explained above.

I wonder why you are unable to reproduce the bug.  For me, it works as
follows:

1) Revert the patch in integral.cpp
2) export CXXFLAGS="-ggdb"  (Well, several others work too, possibly
   any and all)
3) ./configure --disable-shared
4) make
5) make check

Since with GNU ld, initialization depends on the order given on the
link line, please check your link line with mine.  Here is how
ginac/.libs/libginac.a is created:

ar cru .libs/libginac.a  add.o archive.o basic.o clifford.o color.o constant.o ex.o expair.o expairseq.o exprseq.o fail.o fderivative.o function.o idx.o indexed.o inifcns.o inifcns_trans.o inifcns_gamma.o inifcns_nstdsums.o integral.o lst.o matrix.o mul.o ncmul.o normal.o numeric.o operators.o power.o registrar.o relational.o remember.o pseries.o print.o structure.o symbol.o symmetry.o tensor.o utils.o wildcard.o input_parser.o input_lexer.o

And here is how the segfaulting checks/checks executable is created:

g++ -O -o checks check_numeric.o check_inifcns.o check_matrices.o check_lsolve.o genex.o checks.o  ../ginac/.libs/libginac.a -L/usr/lib /usr/lib/libcln.so /usr/lib/libgmp.so

Best wishes
  -richy.
-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>