[osg-users] osgDB ifstream / ofstream conflict

Christiansen, Brad Brad.Christiansen at thalesgroup.com.au
Wed Apr 27 23:55:27 PDT 2011


This seems to be the same / related to an issue raised some time ago with VS2010.

When I build VirtualPlanetBuilder with VS2010 I get errors complaining about duplicate definitions of the stream destructors (cant remember the details of hand). The same code works without issue on non-windows platforms and all other VS compilers tried.

As I don't have time to look into the issue I simply force the link to complete with multiply defined symbols.

A quick search through my local OSG-users archive found the thread + message included bellow. Do a search through the archives around this topic and you should find all the details.



Re: [osg-users] OT: VS2010 LNK2005 problem related to ostringstream

Ok, I have localized the problem.

For example, the class osgDB::fstream:

class OSGDB_EXPORT fstream : public std::fstream


which just inherits from std:.fstream causes the symbols of std::fstream to be exposed into osgDB.dll

This effectively means that It might cause problems for people linking against osgDB.dll later on.
Same goes for inheriting from std::string, std::ostringstream etc.

This must obviously be a bug, a very serious one in VS2010.
We had a class derived from std::ostringstream, which exposed the symbols in the vtable for the class:

namespace ns
class Notify : public std::ostringstream

Using depends.exe to analyze the dll-file gives:

const ns::Notify::`vftable'{for `std::basic_ostringstream<char,struct std::char_traits<char>,class std::allocator<char> >'}

My issue was reported to the msdn forum. Their first take was: Oh you use CMake, thats not our product :-)
But in later threads, they tried to reproduce the problem without luck...
So if you manage to reproduce this in a small example, go ahead and post it. We must make them aware of this problem.



From: osg-users-bounces at lists.openscenegraph.org [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Vincent Bourdier
Sent: Wednesday, 27 April 2011 11:47 PM
To: osg user
Subject: Re: [osg-users] osgDB ifstream / ofstream conflict


Sorry to insist but I would appreciate any advices about this issue. Maybe I'm the only one who encountered it, but the patch I did is not so... "clean" to my mind...



Le 21/04/2011 14:50, Vincent Bourdier a écrit :
Hi all,

I just found a fix after some tests, but it is not a fix I am proud of.
I just added the close() method in osgDB/fstream implementation, so there is no conflict because my fstream implementation uses osgDB/fstream and not osgDB/fstream AND std::fstream.

I will continue to investigate to be sure to understand why this occurs, but any advices or explanations are welcome.
If my fix is accepted this could be a submission for OSG, eventually...



Le 20/04/2011 14:54, Vincent Bourdier a écrit :
Hi Mourad

Thanks for your answer but I already checked that. TsLib_MDdNET2010 is a static lib but linked with /MD(d), like my application...


Le 20/04/2011 11:50, Mourad Boufarguine a écrit :
Hi Vincent,
On Mon, Apr 4, 2011 at 4:36 PM, Vincent Bourdier <vincent.bourdier at gmail.com<mailto:vincent.bourdier at gmail.com>> wrote:
2>TsLib_MDdNET2010.lib(IwPoly.obj) : error LNK2005: "public: void __thiscall std::basic_ifstream<char,struct std::char_traits<char> >::close(void)" (?close@?$basic_ifstream at DU?$char_traits at D@std@@@std@@QAEXXZ) already defined in osgDBd.lib(osg65-osgDBd.dll)
2>TsLib_MDdNET2010.lib(IwBrepData.obj) : error LNK2005: "public: void __thiscall std::basic_ifstream<char,struct std::char_traits<char> >::close(void)" (?close@?$basic_ifstream at DU?$char_traits at D@std@@@std@@QAEXXZ) already defined in osgDBd.lib(osg65-osgDBd.dll)

It seems like a static/dynamic c++ runtime conflict. Check if osg and TsLib_MDdNET2010 are linked against the same type of c++ runtime (both with /MTd flag or both with /MDd flag)


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