Re: [Openexr-devel] pyilmbase problems importing imath

[Federico Naum]

Hello Nick,

Thank you so much for your prompt response.
What you are pointing makes sense, but I think the problem that you are pointing should be Windows only, and as I stated I'm on Linux (Centos 6.2)

I think by default on linux all symbols are exported, and we are not playing with the visibility flags (unless ilmbase/pyilmbase that does that by default? I'll check).

The weird thing is that nobody else seems to have this issue on Linux, and that's why my ugly workaround should not be necessary

I'm going to grab someone else with better c++ skills today to see if we can provide better input to solve this issue.
if you need some other input let me know, but I'll guess you can not repro that in Linux

Cheers
Fede




On 13/02/14 04:06, Nick wrote:

Hello, this issue is the same as described here.

https://github.com/openexr/openexr/issues/86

In your case,the problem stems from the members of the base exception being exported, not the class definition.

The correct fix is to follow through the work in progress on that github thread and commit it to the repo.

I have appended your note to the issue on github for documentation. The issue you reference from the alembic mailing list is the same issue.

Unfortunately, that thread has not been updated in a little while, but it should be possible for anyone with a Windows development set up to pick up the work and send a pull request. At the moment, I personally don't have a windows dev set up, which is why I'm appealing to the list to complete the work.

Regards,

- Nick

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Date: Wed, 12 Feb 2014 18:50:21 +1100
From: address@hidden
To: address@hidden
CC: address@hidden
Subject: [Openexr-devel] pyilmbase problems importing imath

Hi

Hope this is the forum to ask.

I'm building pyilmbase 1.0.0  under llinux Centos 6.2, with ilmbase  1.0.3,  gcc4.1.2 and boost 1.44.0 (also tried all combinations of the newer version of pyilmbase 2.0.0/1 against ilmbase 2.0 with newer compiler gcc446, and several flavours boost.

In all cases I can build  successfully and import iex just fine, but importing imath does SegFault, it does crashed on line 241 of PyIex.h

240│     const TypeTranslator<IEX_NAMESPACE::BaseExc>::ClassDesc *baseDesc = baseExcTranslator().template findClassDesc<ExcBase>(baseExcTranslator().firstClassDesc());
241├>    std::string baseName = baseDesc->typeName();
242│     std::string baseModule = baseDesc->moduleName();

baseDesc ends up with a nullPointer (const PyIex::TypeTranslator<Iex_2_0::BaseExc>::ClassDesc *) 0x0


As importing iex works fine, I changed the code in imathmodule.cpp to kind of copy how the Exception gets registered.

<     PyIex::registerExc<Imath::NullVecExc,Iex::MathExc>("NullVecExc","imath");
<     PyIex::registerExc<Imath::NullQuatExc,Iex::MathExc>("NullQuatExc","imath");
<     PyIex::registerExc<Imath::SingMatrixExc,Iex::MathExc>("SingMatrixExc","imath");
<     PyIex::registerExc<Imath::ZeroScaleExc,Iex::MathExc>("ZeroScaleExc","imath");
<     PyIex::registerExc<Imath::IntVecNormalizeExc,Iex::MathExc>("IntVecNormalizeExc","imath");
---
>     PyIex::registerExc<Imath::NullVecExc,Iex::BaseExc>("NullVecExc","iex");
>     PyIex::registerExc<Imath::NullQuatExc,Iex::BaseExc>("NullQuatExc","iex");
>     PyIex::registerExc<Imath::SingMatrixExc,Iex::BaseExc>("SingMatrixExc","iex");
>     PyIex::registerExc<Imath::ZeroScaleExc,Iex::BaseExc>("ZeroScaleExc","iex");
>     PyIex::registerExc<Imath::IntVecNormalizeExc,Iex::BaseExc>("IntVecNormalizeExc","iex");

This way I can import imath, and in python land I can see that the imath module contains the registered exceptions and I can raise/try/catch them. but this code change seems fishy since nothing else seems to have reported and the code in the latest version remains the same.

I saw someone else did the same change (back in 2012) https://groups.google.com/forum/#!searchin/alembic-discussion/Cannot$20build$20windows/alembic-discussion/OMOvhg0Nv7o/VnJRrByVv10J

but I'm pretty sure I am missing something more obvious

also it caught my attention that I get this warning on gdb

PyIex::TypeTranslator<Iex_2_0::BaseExc>::findClassDesc<Iex_2_0::MathExc> (this=0x6e6510, cd=0x6eaa00) at /scratch/federicon/git/rezExternalPackages/pyilmbase/2.0.0/build/2/pyilmbase-prefix/src/pyilmbase/PyIex/Py
IexTypeTranslator.h:262
(gdb) print cd->typeInfo()
warning: RTTI symbol not found for class 'PyIex::TypeTranslator<Iex_2_0::BaseExc>::ClassDescT<Iex_2_0::BaseExc>'

could it be related to the realtime type info? I made sure that ilmbase and pyilmbase were compiled wihout the -fno-rtti so it should be on by default

Hope someone can help me find the issue

Thanks in advance
Fede



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