double deletion problem with shared pointers.

Nigel Atkinson <[email protected]> Thu, 26 Nov 2009 14:52:43 +1300

Newsgroups	gmane.comp.lang.lua.bind.user
Message-ID	<1259200363.3058.36.camel@hurin>

The attached code shows the double deletion problem I encounted.  I
previously thought that the problem only surfaced when using the
shared_ptr_converter.  However it looks like it happens either way.

Nigel

------------------------------------------------------------------------------
Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day 
trial. Simplify your report design, integration and deployment - and focus on 
what you do best, core application coding. Discover what's new with
Crystal Reports now.  http://p.sf.net/sfu/bobj-july

_______________________________________________
luabind-user mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/luabind-user

main.cpp (text/x-c++src, 1.4 KB)

#include <iostream>
#include <lua.hpp>
#include <luabind/luabind.hpp>
#include <boost/shared_ptr.hpp>
//#include <luabind/shared_ptr_converter.hpp>
#include <string>

using namespace luabind;
using namespace std;

class widget
{
public:
    widget( string caption ) : name(caption)
    {
        cout << "widget constructed: " << this << " " << name << endl;
    }
    virtual ~widget()
    {
        cout << "widget destructed: " << this << " " << name << endl;
    }
protected:
    string name;
};

class widget_wrapper : public widget, public wrap_base
{
    public:
    widget_wrapper( string caption ) : widget( caption )
    {
    }
};

boost::shared_ptr<widget> storage;

void store( boost::shared_ptr<widget> w )
{
	storage = w;
}

void printCount()
{
	cout << "Use count: " << storage.use_count() << endl;
}

void reset()
{
	storage.reset();
}

int main()
{
    lua_State *L;

    L = lua_open();

    luaL_openlibs( L );

    luabind::open( L );

    module(L)
    [
        class_<
			widget,
			widget_wrapper,
			boost::shared_ptr<widget>
			>("widget")
        .def(constructor<string>()),
		def("store", store ),
		def("printCount", printCount ),
		def("reset", reset )
    ];

    if( luaL_dofile( L, "test.lua" ) )
    {
        object error( from_stack( L, 1 ) );
        cout << error << endl;
    }

    lua_close(L);

	cout << "lua closed" << endl;
	printCount();

    return 0;
}

test.lua (text/x-lua, 310 B)

print 'Hello from Lua!'

class 'mywidget' (widget)

function mywidget:__init( name )
    widget.__init(self, name)
end

w = mywidget('Frank')

store(w)

printCount()

w = nil
collectgarbage()
collectgarbage()

printCount()

--reset() -- Calling this b4 the end will stop the segfault happening

print 'Ending'