right place Template specialization

[Andreas Pakulat]

On 31.01.09 13:44:51, Andreas Pakulat wrote:
> On 31.01.09 02:46:45, Patrick Spendrin wrote:
> > Andreas Pakulat schrieb:
> > > Hi, 
> > > 
> > > I've got a tricky problem here and templates are still mysterious to me
> > > outside of the usage of QMap/QList&Co.
> > > 
> > > If you look at
> > > http://websvn.kde.org/trunk/KDE/kdevelop/plugins/languages/cpp/cppduchain/templatedeclaration.cpp?view=markup
> > > http://websvn.kde.org/trunk/KDE/kdevelop/plugins/languages/cpp/cppduchain/templatedeclaration.h?view=markup
> > > 
> > > You'll see
> > > virtual Declaration* resolve(const TopDUContext* /*topContext*/) const
> > > around line 273 in the header and a specialization of this method in line
> > > 1021. As you can see the function in the header asserts in all cases, the
> > > specialization does something useful.
> > > 
> > > Unfortunately for me MSVC always resolves to the non-specialized version in
> > > the header. The template parameter matches as far as I can see during
> > > debugging (no backtrace at hand right now), but msvc still uses the wrong
> > > one. 
> > > 
> > > I could "fix" it by moving the specialization into the header file, but
> > > that breaks compilation on linux/gcc.
> > > 
> > > Anybody have a hint for me whats going wrong here and why MSVC doesn't see
> > > the specialization in the .cpp?
> > What looks not right is that the template class should get exported. 
> > Normally template classes do not get exported (compare Qt 
> > QVector/QList), so I wonder why this should be needed here.
> > I am not sure how this should change anything though as you say it 
> > compiles fine.
> 
> Hmm, but maybe thats the reason it doesn't build on linux anymore when the
> specialization is moved to the header... I'll try removing the export-macro
> and see wether that fixes compilation on linux...

Of course it was not :)

But hopefully the solution is as easy as: Forward declare the function
in the header, but keep the definition in the .cpp. I couldn't test on
msvc and as I still don't understand why it didn't see the
specialization in the .cpp file I can't be sure it works. But I think
chances are good it does :)

Andreas

-- 
Your aim is high and to the right.