Re: [xml] libxml and threads

[Massimo Cafaro <massimo cafaro unile it>]

May be there is a little misunderstanding here.
I said in my first email that it is entirely my fault the problem I am experiencing because I am new to the use of libxml2.
I did not say that libxml2 code leaks memory. I want to make clear again that its is my responsibility, not yours.

I can only say thanks for your suggestions. Unfortunately I did not find a detailed documentation on the web site. This is actually a pity since I firmly believe that libxml2 is a great achievement, but its complexity makes it difficult to use it correctly ( I have been developing unix apps for almost 20 years, including of course threaded apps, so I now exactly what kind of problems can occur).

Thanks again,
Massimo

On Feb 23, 2005, at 12:12 PM, Daniel Veillard wrote:

> On Wed, Feb 23, 2005 at 11:55:41AM +0100, Massimo Cafaro wrote:
> > On Feb 23, 2005, at 11:38 AM, Daniel Veillard wrote: 
> > > > Leak: 0x0110f690  size=48       string 'MUTX'  
> > > > Call stack: [thread 280c000]: | 0x0 | _pthread_body |  
> > > > thread_starter | provider_thr | grelc_get_sql |  
> > > > xmlSAXParseMemoryWithData | xmlCreateMemoryParserCtxt |  
> > > > xmlNewParserCtxt | xmlInitParserCtxt | xmlDefaultSAXHandlerInit | 
> > > >
> > > > __xmlDefaultSAXHandler | xmlGetGlobalState | xmlNewGlobalState |  
> > > > xmlInitializeGlobalState | xmlInitGlobals | xmlNewMutex | malloc 
> > > > |  
> > > > malloc_zone_malloc   
> > >
> > > The threads code is the only one which can legally do direct 
> > > malloc() 
> > > without using xmlMalloc(), so it's among the memory use I won't 
> > > detect 
> > > leaks in regression tests. 
> >
> > I do not understand this. What is exactly what you call threads code? 
>
> code from libxml2 thread.c module.
>
> > The leaks originates in the xmlParseMemory() function, which is called 
>
> No. The leak originate when the application wide thread mutex is
> allocated. The fact it comes from xmlParseMemory() is just that you did
> not initialize the libxml2 module as explained 
> 1/ in the docs
> http://xmlsoft.org/threads.html
> "call xmlInitParser() in the "main" thread before using any of the
> libxml2 API (except possibly selecting a different memory allocator)"
> obviously you are not doing this otherwise that mutex would
> have been allocated by the time you call xmlParseMemory()
> 2/ in my previous mail
>
> > in my application many times in many threads. I do not know exactly how 
> > do you check for leaks, I am using a standard tool on Mac OS X. May be 
> > it is worth saying here that the leaks are exactly the same on linux, 
> > as detected by valgrind. 
>
> Then your code is likely in error, very first thing is to follow the
> documentation about thread safety ! Then come back with a complete
> example reproducing the problem on Linux, not 3 lines out of context.
>
> Daniel
>
>
>
> -- 
> Daniel Veillard      | Red Hat Desktop team http://redhat.com/
> veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
> http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/

-- 

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Massimo Cafaro, Ph.D.        Center for Advanced Computational Technologies
Assistant Professor               Voice  +39 0832 297371    
University of Lecce, Italy      Fax    +39 0832 297279     
Faculty of Engineering         E-mail massimo cafaro unile it            
Via per Monteroni                              cafaro cacr caltech edu
73100 Lecce, Italy                Web     http://sara.unile.it/~cafaro

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