[petsc-dev] IS updates breaking some fortran tests

[Dmitry Karpeev]

I agree that my changes should have nothing to do with VecValid, which
is why this is so baffling.
I've rebuilt the fortran bindings, rebuilt PETSc etc, etc -- to no avail.
I thought it might be a memory corruption due to an expanded IS
struct, but valgrind doesn't detect anything.
This error is the reason I've been sitting on this commit for a while,
but I figured someone else might figure it
out faster than I can :-)
Dmitry.

On Wed, Nov 17, 2010 at 4:19 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
> On Nov 17, 2010, at 4:15 PM, Dmitry Karpeev wrote:
>
>> I just pushed an IS update that causes problems in some fortran tests.
>> I'm not sure exactly what's going on, but a failure occurs, for
>> example, in src/vec/examples/tests/ex1f
>> in VecValid.  Looked at with a debugger it reveals that 'flg', a
>> pointer to boolean that is being passed from Fortran
>> to C, is wiped out and emerges as NULL on the C side (I assume, upon a
>> cast; since there is no temporary
>> in vecvalid_ that holds the result of the "cast", I can't really
>> examine the intermediate value passed to C).
>>
>> I've been trying to figure this out for a bit, but have come up with
>> nothing so far (e.g., valgrind runs on ex1f fine).
>> I'm sure this will show up in the nightly builds, but I figured I'd
>> push this change, hoping that someone with a
>> better knowledge of Fortran bindings will help me figure this out.
>>
>> Thanks.
>> Dmitry.
>
>  Huh, your changes shouldn't have anything to do with VecValid, nor affect it in any way. Any problem should exist both with or without your changes
>
>   BTW: VecValid() is not a legitimate function, should never be used and should be removed from PETSc-dev ASAP. Why it is too dangerous poking around with an unknown pointer.
>
>   Barry
>
>
>