noncopyable static const member class in template class
- by Dukales
I have a non-copyable (inherited from boost::noncopyable) class that I use as a custom namespace. Also, I have another class, that uses previous one, as shown here:
#include <boost/utility.hpp>
#include <cmath>
template< typename F >
struct custom_namespace
: boost::noncopyable
{
F sqrt_of_half(F const & x) const
{
using std::sqrt;
return sqrt(x / F(2.0L));
}
// ... maybe others are not so dummy const/constexpr methods
};
template< typename F >
class custom_namespace_user
{
static
::custom_namespace< F > const custom_namespace_;
public :
F poisson() const
{
return custom_namespace_.sqrt_of_half(M_PI);
}
static
F square_diagonal(F const & a)
{
return a * custom_namespace_.sqrt_of_half(1.0L);
}
};
template< typename F >
::custom_namespace< F > const custom_namespace_user< F >::custom_namespace_();
this code leads to the next error (even without instantiation):
error: no 'const custom_namespace custom_namespace_user::custom_namespace_()' member function declared in class 'custom_namespace_user'
The next way is not legitimate:
template< typename F
::custom_namespace< F const custom_namespace_user< F ::custom_namespace_ = ::custom_namespace< F ();
What should I do to declare this two classes (first as noncopyable static const member class of second)? Is this feaseble?
