Re: [xml] LIBXML_THREAD_ENABLED and HAVE_PTHREAD_H mismatch

[Roumen Petrov <bugtrack roumenpetrov info>]

Adrian Bunk wrote:
> On Fri, Nov 19, 2010 at 10:00:38PM +0200, Roumen Petrov wrote:
>    
> > [SNIP]
> >      
> > > > > > Kwasi Mensah wrote:
> > > > > > I ran into the issue where HAVE_PTHREAD_H is defined but
> > > > > > LIBXML_THREAD_ENABLED wasn't. The fix was already submitted as per
> > > > > > http://mail.gnome.org/archives/xml/2005-August/msg00136.html  .
> > > > > >
> > > > > > Out of curiosity, is there a reason this patch didn't get into that main
> > > > > > line?
> > > > > >
> > > > > > This is with libxml2 2.7.8 on Mac OS X. I ran the configure script but
> > > > > >
> > > > > >              
> > [SNIP]
> > In summary :
> > - gcc -pthread defines _REENTRANT on linux
> > - gcc -pthread does not define preprocesor macros on FreeBSD and OS
> > X(darwin).
> >
> > I guess other BSDs to be similar as FreeBSD.
> > No Idea how to resolve properly issue.
> >      
> The proper solution would be to:
> - get rid of the #if's in xmlversion.h.in and
> - set one threads variable in configure.ac when using threads and
> - *if* that variable is set, set an additional variable in
>    configure.ac specifying which threads type is used
>    
As Daniel is author of the code I would like to leave to him to detail. 
Lets see the code
#if @WITH_THREADS@
#  if XXX
....
#  endif /*XXX*/
#endif
as @WITH_THREADS@ depend from configure script/settings/detection.

If i understand properly if libxml is compiled :
- without threading support to forbid third party to use threading. In 
this case @WITH_THREADS@ will be zero and nested if are not applicable.
- with threading support to enable/disable threading for third party 
depending from some flags. In this case @WITH_THREADS@ will be one and 
nested #if is applicable.

The issue is with second case - how thread aware libxml to detect that 
third party application/library require threading.

Roumen