template linking

[illario]

Hello,
how I can get it linked?

nr.h

namespace NR {
template <typename T>
T mpoint2(const std::map<T, T> &data, const T x);
}

template <typename T>
T NR::mpoint2(const std::map<T, T> &data, const T x) {
 typedef typename std::map<T, T>::const_iterator iter;
 ...
}

main.cpp

double E,y;
std::map<double, double> escs;

y = NR::mpoint2(escs,E);
...

undefined reference to `double NR::mpoint2<double>(std::map<double, double, std::less<double>, std::allocator<std::pair<double const, double> > > const&, double)'

[Peter87]

I don't see a problem with the code you have posted. Could perhaps post a complete example.