template specialization compile error on MSVC.NET 2003

[Butterfly]

This code below can compile properly on MSVC 6.0 but cannot on MSVC .NET 2003. Does anyone know what's going on ??

template <class T, class U>
void ReadRNet(int& a, U** b, T* c = NULL)
{
	// DO something here.
	return;
}

template<>
void ReadRNet<int, char*>(int& a, char* b)
{
	// Do something here.
	return;
}

// error C2912: explicit specialization; 'void ReadRNet<int,char*>(int&,char**  )' is not a specialization of a function template

[Butterfly]

correct error message above.

template <class T, class U>
void ReadRNet(int& a, U** b, T* c = NULL)
{
	// DO something here.
	return;
}

template<>
void ReadRNet<int, char*>(int& a, char* b)
{
	// Do something here.
	return;
}

// error C2912: explicit specialization; 'void ReadRNet<int,char*>(int&,char*  )' is not a specialization of a function template

[jonnin]

6 is less than standard and forgives a lot of "not quite correct" code. When in doubt, .net is normally correct.

I think you need the template args in the <> on the bottom one?

[Danny]

You can't define a partial specialization of a function template in C++. This is possible only with class templates. You can however define an *overloaded* version of the said function, which means that you should get rid of the template <>
part, and that would turn the "specialization" into an ordinary overloaded functions. In general if Visual 7.0 rejects code that compiled fine under VC++ 6, it's right.

[Butterfly]

Danny, what's partial & fully specialization ?

[Danny]

a partial specialization selects a subset of the template instances from the primary template. So if you have a template X<T>, in which T can be any type, a partial specialization thereof can look like X<T*> which applies only to pointers, but this is still an infinitr set of template specializations (i.e., instances) because you can define an endless number of pointer types. A full specialization is simply a template instance: X<int>, X<char*> etc.

You can read more about this here:
http://www.informit.com/guides/conte...plus&seqNum=49
and
http://www.informit.com/guides/conte...plus&seqNum=50