Re: declaring a friend template function whose arguments are of type = private member type

Basically, in your case EntryType type is always a specialization of
std::pair<> template. That template defines =93less than=94 comparator by
default, it looks like this (defined trough including 'utility' header
from STL):

  template<class _T1, class _T2>
    inline bool
    operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    { return __x.first < __y.first
         || (!(__y.first < __x.first) && __x.second < __y.second); }

So you are good as long as both types =93CurveTraits::tType=94 and
=93CurveTraits::fType=94 has =93less than=94 operators defined. Note that y=
ou
don't have to define =93bool operator < (const EntryType & lhs, const
EntryType & rhs)=94 yourself.

For example, let's assume you have the following code that uses your
=93TimeCurve1D=94 template:

struct A { int v; };
struct B { double v; };

struct my_curve_traits {
    typedef A tType;
    typedef B fType;
};

In order to get it working you have to write the following operators:

bool operator < (const A & lhs, const A & rhs) { return lhs.v <
rhs.v; }
bool operator < (const B & lhs, const B & rhs) { return lhs.v <
rhs.v; }

Note that you don't have to define those operators for POD types (line
int, double etc.). This is an example:

#include <utility>
#include <stdexcept>
#include <iostream>

#include <boost/array.hpp>

template<typename CurveTraits>
class TimeCurve1D
{
public:
  typedef typename CurveTraits::tType tType;
  typedef typename CurveTraits::fType fType;

  fType GetSomething() const { throw std::runtime_error("Not
implemented"); }

private:
  enum { mContainerMaxSize = 128 }; // You probably forgot to define
mContainerMaxSize...

  typedef std::pair<tType,fType> EntryType;
  typedef boost::array< EntryType, mContainerMaxSize > ContainerType;

  ContainerType m;
  size_t mContainerSize;
};

struct A { int v; };
struct B { double v; };

struct my_curve_traits {
    typedef A tType;
    typedef B fType;
};

typedef TimeCurve1D<my_curve_traits> my_curve_1d;

int main(int , char *[]) {
    try {
        my_curve_1d curve;
        curve.GetSomething();
    } catch(const std::exception & e) {
        std::cout << "Here you go: " << e.what() << std::endl;
    }
    return 0;
}

Hope it helps!

---
Vladyslav Lazarenko