Re: "default template arguments may not be used in function templates"

[Vincent Torri <Vincent dot Torri at iecn dot u-nancy dot fr>]

Hello,

It does help !

Thank you very much

Vincent

On Mon, 4 Jul 2005, Travis Spencer wrote:

> On 7/4/05, Vincent Torri <Vincent.Torri@iecn.u-nancy.fr> wrote:
> >
> > Hello,
>
> Hey, Vincent.
>
> > I have the following class:
> >
> > template <typename T, typename Synchronizer = synchronizer::None, typename
> > Creator = T * (*)()>
> > class value_cache
> > {
> >   ***
> >
> > public:  //interface
> >
> >   boost::shared_ptr<T> Get() const
> >   {
> >     Synchronizer synchronizer();
> >
> >     ***
> >     ***
> >   }
> > };
> >
> > But gcc reports this error message at compile time:
> >
> > "default template arguments may not be used in function templates"
> >
> > for the declaration of synchronizer().
> >
> > I use gcc 3.3.4
>
> You can't use the default arguments in the function declaration (see
> http://tinyurl.com/bvnbx).  To get around this, declare the class
> methods in the header file like normal, but define them after the
> class declaration (in the same header file) kinda like this:
>
> // -*- mode: c++ -*-
> // value_cache.h
> #include <boost/shared_ptr.hpp>
>
> class synchronizer {
>     class None { };
> };
>
> template <typename T, typename Synchronizer = synchronizer::None,
>           typename Creator = T * (*)() >
> class value_cache
> {
> public:
>     typedef boost::shared_ptr<T> SharedPtr;
>
>     SharedPtr Get() const;
> };
>
> #define ValueCache value_cache<class T, class Synchronizer, class Creator>
>
> inline ValueCache::SharedPtr ValueCache::Get() const
> {
>     Synchronizer synchronizer();
> }
>
> HTH.
>
> --
>
> Regards,
>
> Travis Spencer
> Portland, OR USA
>