2010/2/24 James Amundson <amundson@fnal.gov>

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

_______________________________________________
Cplusplus-sig mailing list
Cplusplus-sig@python.org
http://mail.python.org/mailman/listinfo/cplusplus-sig

_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
http://lists.boost.org/mailman/listinfo.cgi/boost-users