id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
1952	[saywhat] The operation static_cast<std::string>(boost::python::extract<std::string>(...))  crashes Python. Seems to create reference counting problem.	Konstantin Aslanidi <konstantin.aslanidi@…>	Dave Abrahams	"I submit boost::python based python extension code that crashes Python interpreter when used as described below. I attach Visual Studio .NET project files.

C:\KDocuments\Variance Swap Validation 2\VarSw2\Debug>python
ActivePython 2.5.2.2 (ActiveState Software Inc.) based on
Python 2.5.2 (r252:60911, Mar 27 2008, 17:57:18) [MSC v.1310 32 bit (Intel)] on
win32
Type ""help"", ""copyright"", ""credits"" or ""license"" for more information.
>>> import vrsw2
>>> p=vrsw2.VarSwapTest()
>>> p.set(((1,2),(3,4)))
<crash here>

The C++ extension code:
#include <string>
#include <fstream>
#include <boost/python.hpp>
#include <boost/shared_ptr.hpp>
using namespace boost::python;


class VarSwapTest
{
private:
	class Impl
	{
        private:
			std::ofstream theFile;
		public:
			Impl()
				: theFile(""VarSwapTestEcho.txt"")
				{}

			void set( object& input )
			{
				object o=input.attr(""__str__"")();
				extract<std::string> ex(o);
				if( ex.check() )
					theFile<<(static_cast<std::string>(ex()))<<std::endl;
				else
					theFile<<""failed to extract string""<<std::endl;
			}
	};
private:
	boost::shared_ptr<Impl> theImpl;
public:
	VarSwapTest() : theImpl(new Impl()) {}
	void set( object input )
	{
		theImpl->set(input);
	}
};

BOOST_PYTHON_MODULE(vrsw2)
{
	class_<VarSwapTest>(""VarSwapTest"")
		.def(""set"",&VarSwapTest::set)
	;
}
"	Bugs	closed	Boost 1.36.0	python USE GITHUB	Boost 1.35.0	Showstopper	worksforme	python extract	troy@…