Lucas
Fri Nov 21 00:21:57 CST 2003
thx
"John Carson" <donaldquixote@datafast.net.au> wrote in message
news:O3VUFR$rDHA.536@tk2msftngp13.phx.gbl...
> "Lucas Galfaso" <lgalfaso@NO_CAPSfd.com.ar> wrote in message
> news:eyhpWy%23rDHA.3492@TK2MSFTNGP11.phx.gbl
> > If you want to define a member function from a partially specialized
> > class, you MUST predeclare the partial specialization, but if you
> > want to define a member function of a fully specialized class, you
> > MUST NOT predeclare the full specialization.
> >
> > example
> >
> >
> > // full specialization
> >
> > template <int a>
> > struct P {
> > void f();
> > };
> >
> > // uncomment this and get an error
> > /*
> > template <>
> > struct P<0>
> > {
> > void f();
> > };
> > */
> >
> > template <>
> > void P<0>::f() {}
> >
> >
> >
> >
> > // partial specialization
> >
> > template <int a, int b>
> > struct S {
> > void f();
> > };
> >
> > // comment this and get an error
> > template <int a>
> > struct S<a, 0> {
> > void f();
> > };
> >
> > template <int a>
> > void S<a, 0>::f () {}
> >
> >
> > Lucas/
>
>
> I believe the rules for full specialisation are as follows.
>
> You can fully specialise an entire class (or struct) or you can fully
> specialise one or more member functions without specialising the class as
a
> whole. The distinction between these two is somewhat obscured when your
> class has only a single member.
>
> If you fully specialise a class, then you predeclare the specialised class
> in its entirety (the specialised version may but need not have any members
> in common with the non-specialised version) and then you must define EVERY
> member function of the specialised class. In making these definitions, you
> OMIT the template<> keyword from function definitions. Thus you would
have:
>
> template <int a>
> struct P {
> void f();
> };
>
> template <>
> struct P<0>
> {
> void f();
> };
>
>
> // no template<> here
> void P<0>::f() {}
>
> If you only specialise one or more member functions, but leave the class
> itself unspecialised, then you obviously don't need to give a declaration
of
> the specialised class. Thus you would have:
>
> template <int a>
> struct P {
> void f();
> };
>
> template<>
> void P<0>::f() {}
>
>
> When it comes to partial specialisation, it is not possible to partially
> specialise just a member function; you have to partially specialise the
> class as a whole. Thus you must pre-declare the entire class and define
all
> of its members. Unlike in the case of full specialisation, you still need
> the template <??> keyword when defining member functions because, of
course,
> there is still a template parameter involved in the class.
>
>
>
> --
> John Carson
> 1. To reply to email address, remove donald
> 2. Don't reply to email address (post here instead)
>