sfinae

I've found similar cases, but they usually ended up doing something along the lines of what I (think) I'm doing here. I want to be able to call a function with one or more parameters, obviously, if the function exists with overloads with multiple parameters, the correct version cannot be deduced without help. As I am specifying the number of arguments as well, I figured this would be enough information for the compiler to deduce the correct overload. This doesn't seem to be the case and I hope you may be able to show me why. the code: http://coliru.stacked-crooked.com/a/5e6fd8d5418eee3c

In the example below, I need to extract some values. I have an efficient extractor, which can work with builtin types, and an inefficient template that can work with everything. To choose between these, I want to use Function Overloading Based on Arbitrary Properties of Types . Here is my code: #include <string> #include <iostream> class extractor { public: static void extract(const bool& val) { std::cout << "Specialized extractor called" << std::endl; } static void extract(const double& val) { std::cout << "Specialized extractor called" << std::endl; } }; template <typename T> void extract

I want to write a trait that returns the integral type (float, int, char...) of a given type. Base is: template< class T, typename T_SFINAE = void > struct IntegralType; template< class T > struct IntegralType< T, std::enable_if< (std::is_integral<T>::value || std::is_floating_point<T>::value) > >{ using type = T; } template< class T > struct IntegralType<T>: IntegralType<T::type>{} And I want it to return double for: struct foo{ using type = double; } struct bar{ using type = foo; } IntegralType<double>::type == double IntegralType<foo>::type == double IntegralType<bar>::type == double This

My question is an extension of this question: How to use sfinae for selecting constructors? In the previous question, the asker just wanted to selectively enable a single constructor. I would like to change the behaviour of the constructor depending on whether the class template parameter type is default-constructible - the best way that I can come up with to do this is to have two constructors with the same usage such that exactly one is enabled for every instantiation. My case is also different because neither version of the constructor would be a template function if I weren't trying to

template<typename T, size_t M, size_t K, size_t N, typename std::enable_if_t<std::is_floating_point<T>::value, T> = 0> void fastor2d(){//...} I copied this line of code from cpp-reference(only the std::enable_if part, i do need T and all three of the size_t 's), because i would like to use this function only when floating_types are used on it ... it does not compile. Could somebody explain to me, why, and what it even does? While i am at it, how do you call this function afterwards? Every tutorial or question here on SO gets bombed with answers, and that is great, but to someone who does not