Re: [Boost-users] [C++-sig] Boost python exception translation failure on BlueGene/P

Subject: Re: [Boost-users] [C++-sig] Boost python exception translation failure on BlueGene/P
From: James Amundson (amundson_at_[hidden])
Date: 2010-02-24 12:37:22

On 02/18/2010 04:24 PM, James Amundson wrote:
> Boost Python seems to be failing to catch and translate C++ exceptions 
> for me on a BlueGene/P installation. I really don't know what to do 
> next in debugging the problem, so I would appreciate any advice.

I have finally solved this problem myself -- I am responding to my own 
message on these mailing lists in case this information is useful to 
others.

In the end the solution was to add the flag "-dynamic" to the 
libboost_python link line. Without the flag, boost::python mostly works 
on BlueGene/P, but exceptions are not caught. With the flag, 
boost_python passes all tests I have done.

I spent some time trying to understand how to tell bjam to add a flag to 
the boost_python link line, but I gave up after about fifteen minutes. 
With the CMake build of boost, it was easy: I simply did
     cmake -DCMAKE_SHARED_LINKER_FLAGS="-dynamic"
Overall, I found dealing with the cmake build of boost so much more 
pleasant than dealing with bjam that I don't understand why the CMake 
build hasn't taken over the mainstream yet.

--Jim Amundson

P.S. The original problem report:
> I have a simple test module, pyexcept
> ------------------------------------------------------------
> #include <boost/python.hpp>
> #include <iostream>
> #include <stdexcept>
>
>
> void
> foo()
> {
>     std::cout << "in foo, about to raise exception\n";
>     throw std::runtime_error("runtime_error from foo");
>     std::cout << "this should never be seen\n";
> }
>
> using namespace boost::python;
>
> BOOST_PYTHON_MODULE(pyexcept)
> {
>     def("foo",foo);
> }
> ------------------------------------------------------------
>
> I test it with the following python script:
> ------------------------------------------------------------
> #!/usr/bin/env python
>
> import pyexcept
>
> print "about to run pyexcept.foo, catching exception"
> try:
>     pyexcept.foo()
> except RuntimeError,e:
>     print "caught RuntimeError,",e
> ------------------------------------------------------------
>
> On my Linux machine I see:
> ------------------------------------------------------------
> about to run pyexcept.foo, catching exception
> in foo, about to raise exception
> caught RuntimeError, runtime_error from foo
> ------------------------------------------------------------
>
> On the BlueGene/P machine I see:
> ------------------------------------------------------------
> about to run pyexcept.foo, catching exception
> in foo, about to raise exception
> terminate called after throwing an instance of 'std::runtime_error'
>   what():  runtime_error from foo
> ------------------------------------------------------------
>
> I have (cross-)compiled boost myself using the system's installed 
> version of the gnu compilers, 4.1.2:
> ------------------------------------------------------------
> |login2>mpicxx.gnu --version
> powerpc-bgp-linux-g++ (GCC) 4.1.2 (BGP)
> ------------------------------------------------------------
>
> (The mpicxx.gnu script is a wrapper around the cross-compiling g++.) 
> Has anyone seen a problem like this? Any ideas as to how to debug it?
>
> Thanks for any advice.
>
> --Jim Amundson
>
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