[C++-sig] Re: member function template question.
dave at boost-consulting.com
Thu Feb 19 21:31:25 CET 2004
"Ralf W. Grosse-Kunstleve" <rwgk at yahoo.com> writes:
> Your example has several layers of complexity. I believe the main trick you
> need to know is how to use a cast to tell the compiler what you want. E.g.:
> template <typename FloatType>
> vec3<FloatType> const& eigenvalues,
> FloatType const& tolerance);
> (bool(*)(vec3<double> const&, double const&)) is_positive_definite);
> This is a bit cumbersome but somehow you have to define which FloatType you
> want to use since you are crossing the boundary between compile-time
> polymorphism and runtime polymorphism.
That won't work because is_positive_definite is a template, not a
function. You can't cast templates.
You can only wrap a particular *instantiation* of a function template.
I suggest picking a FloatType (probably double), and wrapping
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