pthread_exit and STL problems

pthread_exit and STL problems

[Stefan Eilemann]

Hi,

I am tracking down a problem in my code using VC++ 8.0 and
pthreads-win32 2.8.0. My hope is that somebody on the list has
seen (and solved) this problem.

In my code I am removing elements from a std::vector<>, which
works fine until the first pthread has exited. After this point,
I am getting a crash in the debug version when erasing an element
from the vector:

     vector<Object*>::iterator iter    = find( objects.begin(),  
objects.end(),
                                               object );
     if( iter == objects.end( ))
         return;

     objects.erase( iter );


This is the call stack:


  Equalizer.dll!std::vector<eqNet::Object  
*,std::allocator<eqNet::Object *> >::_Orphan_range(eqNet::Object * *  
_First=0x0038c830, eqNet::Object * * _Last=0x0038c834)  Line 1233 +  
0x5 bytes
Equalizer.dll!std::vector<eqNet::Object  
*,std::allocator<eqNet::Object *> >::erase 
(std::_Vector_iterator<eqNet::Object *,std::allocator<eqNet::Object  
*> > _Where=0x00395fe0 {_initData={...} _frameData={...}  
_displayLists={...} })  Line 990
Equalizer.dll!eqNet::Session::removeRegisteredObject(eqNet::Object *  
object=0x00395fe0, eqNet::Object::SharePolicy policy=SHARE_NODE)   
Line 304 + 0x29 bytes
Equalizer.dll!eq::Node::_cmdDestroyPipe(eqNet::Command & command= 
{...})  Line 134	C++


The code in question seems to invalidate all iterators of the vector.
The crash happens because _Pnext gets an invalid pointer after some
iterations:


#if _HAS_ITERATOR_DEBUGGING
	void _Orphan_range(pointer _First, pointer _Last) const
		{	// orphan iterators within specified (inclusive) range
		_Lockit _Lock(_LOCK_DEBUG);
		const_iterator **_Pnext = (const_iterator **)&this->_Myfirstiter;
		while (*_Pnext != 0)
			if ((*_Pnext)->_Myptr < _First || _Last < (*_Pnext)->_Myptr)
				_Pnext = (const_iterator **)&(*_Pnext)->_Mynextiter;
			else
				{	// orphan the iterator
				(*_Pnext)->_Mycont = 0;
				*_Pnext = (const_iterator *)(*_Pnext)->_Mynextiter;
				}
		}
#endif /* _HAS_ITERATOR_DEBUGGING */


Again - this code is called numerous time before without problem. The
first time the crash happens is when a pthread has been exit'ed, and
the calling thread just called pthread_join() shortly before the call
above. I am linking against the multithreaded debug runtime.

Has anybody seen this already? Does the thread exit code cleanup/ 
interfere
with the VC8 STL implementation? Any hints?


Cheers,

Stefan.
-- 
http://www.equalizergraphics.com
http://www.linkedin.com/in/eilemann

Re: pthread_exit and STL problems

[Stefan Eilemann]

On 31. Jan, 2007, at 0:13 , Ross Johnson wrote:

Hello Ross,

> My C++ is very limited but I have a couple of general questions and  
> possibly redundant general comments.
>
> You're using pthreads-win32 2.8.0 but which version of the DLL are  
> you using, VC or VCE?

I am using pthreadVC2.

> Are you building the pthreads library from source? The packaged  
> dlls are built using VC6 and the BUGS file in the pthreads  
> distribution refers to problems relating to the VCE dll which may  
> or may not be VC version specific.

I am using the packaged DLL. Since I am using the VC version, it is my
understanding that this doesn't matter.

>
> Does trying any of the above alternatives avoid the problem?

I've just tried to build the library myself using VC8.0.

Using 'nmake clean VC' path failed, since the resulting library
was referencing msvcrt80.dll, which the executable couldn't find.

Converting the .dsw file in VS2005 and using it resulted in a
usable library - though I am not sure which 'version' I have.
__CLEANUP_C and  PTW32_BUILD are defined. Can you enlighten me?
Do I need to define __CLEANUP_C during my build as well? I am
just a bit nervous using a library where I haven't fully grokked
the side effects.


Cheers,

Stefan.
-- 
http://www.equalizergraphics.com
http://www.linkedin.com/in/eilemann

RE: pthread_exit and STL problems

[Streithorst, Kip]

The reason the executable couldn't locate msvcrt80.dll is because you
will have to install the Visual Studio 8 redistributable which can be
found in " C:\Program Files (x86)\Microsoft Visual Studio
8\SDK\v2.0\BootStrapper\Packages\vcredist_x86" of a Visual Studio
install.  Or you can read more at Microsoft's website.  The other thing
you have to do is embed the manifest into the pthreadVC2.dll after is
generated.  This is a new requirement Microsoft added for Visual Studio
8. 

Ross,
The embedding of the manifest in the dll is another thing besides the
warnings that has to be dealt with.

Thanks,
Kip

-----Original Message-----
From: pthreads-win32-owner@sourceware.org
[mailto:pthreads-win32-owner@sourceware.org] On Behalf Of Stefan
Eilemann
Sent: Wednesday, January 31, 2007 4:00 AM
To: Ross Johnson
Cc: Pthreads-Win32 list
Subject: Re: pthread_exit and STL problems


On 31. Jan, 2007, at 0:13 , Ross Johnson wrote:

Hello Ross,

> My C++ is very limited but I have a couple of general questions and  
> possibly redundant general comments.
>
> You're using pthreads-win32 2.8.0 but which version of the DLL are  
> you using, VC or VCE?

I am using pthreadVC2.

> Are you building the pthreads library from source? The packaged  
> dlls are built using VC6 and the BUGS file in the pthreads  
> distribution refers to problems relating to the VCE dll which may  
> or may not be VC version specific.

I am using the packaged DLL. Since I am using the VC version, it is my
understanding that this doesn't matter.

>
> Does trying any of the above alternatives avoid the problem?

I've just tried to build the library myself using VC8.0.

Using 'nmake clean VC' path failed, since the resulting library
was referencing msvcrt80.dll, which the executable couldn't find.

Converting the .dsw file in VS2005 and using it resulted in a
usable library - though I am not sure which 'version' I have.
__CLEANUP_C and  PTW32_BUILD are defined. Can you enlighten me?
Do I need to define __CLEANUP_C during my build as well? I am
just a bit nervous using a library where I haven't fully grokked
the side effects.


Cheers,

Stefan.
-- 
http://www.equalizergraphics.com
http://www.linkedin.com/in/eilemann

Re: pthread_exit and STL problems

[Stefan Eilemann]

On 1. Feb, 2007, at 13:40 , Ross Johnson wrote:

> Stefan Eilemann wrote:
>> Yes - I tested the generated pthreadVC2.dll, and the crash  
>> disappeared.
> That's great. I'll have to see if I can get myself an updated VS.

To summarize: Using the VC8 compiler fixed the problem for me.

I am using the VC8-build version of pthreadVC2 for a couple of days
now in my project, without problems. In case I'll bump into an issue
again, I'll let you know.


Cheers,

Stefan.
-- 
http://www.equalizergraphics.com
http://www.linkedin.com/in/eilemann