Re: [xml] libxml2-2.7.8 and MinGW

[Earnie <earnie users sourceforge net>]

Roumen Petrov wrote:
> Earnie wrote:
> > Earnie wrote:
> > > Roumen Petrov wrote:
> > > > Earnie wrote:
> > > > > Earnie wrote:
> > > > > > I've been building libxml2-2.7.8 and have been having a heck of
> > > > > > a time getting xmlcatalog to work with a shared DLL library.
> > > > > > I've finally confirmed that the issue is caused by optimizations
> > > > > > with -O2 or -O1. If I use -O0 the issue goes away. The effect is
> > > > > > the xmlIsPubidChar_tab array is seen by xmlcatalog to contain all
> > > > > > 0x00 values. I'm using GCC-4.6.1 and binutils-2.21.53.20110804
> > > > > > as delivered by MinGW. I wanted give this list a report of what
> > > > > > I've found in the event others come by, they may have already.
> > > > hmm ,
> > > >
> > > > Look like regression as it is fine with me for gcc/binutils: -
> > > > 3.4.5/2.17.50 20070129 - 4.4.0/2.19.1
> > > It was Kai Tietz who is active in GCC development for Windows and one of
> > > its maintainers who pointed me to the issue resolution.
> > >
> > > See http://thread.gmane.org/gmane.comp.gnu.mingw.user/38000 for the
> > > discussion.
> [SNIP]
> Above like is fine to follow the thread .
> I'm not against the patch
> a) it will resolve linking issue if libxml2 is build with gcc (mingw)
> and -nocommon flag.
> b) it will resolve issue with new gnu compiler/linker
> c) libxslt and xmlsec for instance use extern for mingw* compilers
>
> Lets first finish discussion on mingw list as libxml and libxslt does
> not use extern for cygwin compiler. If cygwin build is impacted then
> complete patch must cover both woe compilers. Also  another patch for
> libxslt is required .

As discussed on the MinGW list here are the patches for both libxml2 and
libxslt adorning dllexport with extern for both __CYGWIN__ and __MINGW32__.

During the discussion on the MinGW list we discovered the following bit
of information about dllexport:

From:
http://msdn.microsoft.com/en-us/library/y4h7bcy6.aspx

The use of dllexport implies a definition, while dllimport implies a
declaration. You must use the extern keyword with dllexport to force a
declaration; otherwise, a definition is implied.

-- 
Earnie
-- https://sites.google.com/site/earnieboyd/