work on dynamic libraries finished and ready for review

[Lisandro Dalcin]

On Tue, Oct 28, 2008 at 4:43 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>   I'm curious why you didn't go all the way and make it a full
> PETSc object (like I suggested). Did you have technical reasons
> or was it mostly just fear of breaking something? I'm in the mood
> to have it be "right" for our release coming up soon.
>

Just because I'm not still sure if the added complexity will really
pay. I want to think a bit more about all this.

Whith the current implementation, I'm being able to dynamically load a
Python shared library, dlsym() Python API calls to initialize Python,
bootstrap petsc4py, and finally create Python-implemented
matrix/ksp/pc/snes/ts objects inside let say a .py file in the working
directory. So all my fixes seems so be enough for such rather
'complex' tasks.

To be completelly clear: The only lacked feature is the ability of
passing flags to dlopen(). And in the case of Windows, such flags do
not make sense and they are ignored.


>  I agree, it should handle file:// in the standard manner (I think
> it is the way it is because it was a simple hack to get file: working.
>>

OK, then 'file://' will be accepted, but a bare 'file:' will likely
generate an error. Is this right? Or should I try to parse harder and
accept any of 'file:', 'file:/', file://' ??


>> * When PetscFinalize() is called, now dynamic libraries are actually
>> dlclose'd. But the dynlib list is traversed from the first entry to
>> the last. Perhaps this could cause problems in some rare cases, and we
>> should do a reversed traversal.
>
>  This sounds like it should be changed as you suggest.

But then the library list should be a double-linked?. Or a O(N**2)
go-to-end and remove-end whould be enough? IMHO, there is no point on
optimizing this, right?

>   Feel free to push over after the changes you suggested above.

OK, but please answer to the above questions.


-- 
Lisandro Dalcín
---------------
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