Question

I am wondering why the following contrived example code works perfectly fine in Visual Studio 2005, but generates an error in GCC (‘no matching function to call’ when calling Interpolate() as shown below).

Also, how do I work around this? It seems that the error message is just a generic message because GCC did not have a more specific message for the actual reason of the problem and it had to output something. I’m a bit at a loss on how to proceed porting this class without some really ugly workarounds.

namespace Geo {     template <class T>     class TMyPointTemplate     {         T X,Y;     public:         inline TMyPointTemplate(): X(0), Y(0) {}         inline TMyPointTemplate(T _X,T _Y): X(_X), Y(_Y) {}         inline T GetX ()const { return X; }         inline T GetY ()const { return Y; }         //...         template<T> TMyPointTemplate<T> Interpolate(const TMyPointTemplate<T> &OtherPoint)const         {             return TMyPointTemplate((X+OtherPoint.GetX())/2,(Y+OtherPoint.GetY())/2);         }                };     typedef TMyPointTemplate<int> IntegerPoint; }  Geo::IntegerPoint Point1(0,0); Geo::IntegerPoint Point2(10,10); Geo::IntegerPoint Point3=Point1.Interpolate(Point2); //GCC PRODUCES ERROR: no matching function for call to 'Geo::TMyPointTemplate<int>::Interpolate(Geo::IntegerPoint&)' 

Thanks for your help,

Adrian

Answer 1

I don’t think you need the template there at all in the function definition, since it is defined inline with the class

TMyPointTemplate Interpolate(const TMyPointTemplate &OtherPoint)const { 

should do.

And when you do use the template for defining the function not inline, I think you need the class keyword in there like this.

template<class T> // <- here TMyPointTemplate<T> TMyPointTemplate<T>::Interpolate(const TMyPointTemplate<T> &OtherPoint)const {