In C++ Weekly - Ep 313 - The constexpr Problem That Took Me 5 Years To Fix!, Jason Turner demonstrates several compile-time techniques in order to construct a std::string at compile-time and then p...

Consider this code: #include <type_traits> template <typename T> struct wrapper { T& ref; constexpr wrapper(T& ref) : ref(ref) {} }; // Trait that checks whether a type is o...

Somehow I still think of lambdas as "syntactic sugar" for regular function objects, so it surprises me that under C++-20 a stateful but otherwise constexpr lambda instance cannot be...

I am working with a library which exposes an interface to work with. One of the functions of this library is like this : template <int a> void modify(){} I have to modify parameters from 1 t...

When declaring a template, I am used to having this kind of code: template <class T> But in this question, they used: template <unsigned int N> I checked that it compiles. But wha...

I have this class template <typename ValueType, std::size_t Size> struct ArrayPrimitive { constexpr ArrayPrimitive(const ValueType (&array)[Size]) { std::copy(array, array + Size, data_...

Why this application doesn't compile? #include <iostream> #include <array> template<int N> std::ostream& operator << (std::ostream& out, std::array<int, N&...

template<template<auto> class> struct A {}; template<int&> struct B {}; A<B> a; int main() {} All three compilers MSVC, GCC and Clang in their latest versions accept ...

#include<type_traits> template <typename T, T> struct A { }; template <typename T, T t> void f(A<T, t>) { } int main() { f(A<const int, 0>{}); } https://godbolt.o...

In my previous question (Is it legal to use an unexpanded parameter pack as the type of a template template parameter's non-type template parameter?), it was pointed out that it is not legal to...

Suppose we have the following program: template <class T, T n1, T n2> struct Probe { static const int which = 1; }; template <class T, T n> struct Probe<T, n, n> { static con...

msvc compiles the following code(with /permissive- compiler switch), clang and gcc do not: template<auto val> struct S{ static constexpr auto val = val; }; int main() { return S<4>::v...

Assume I want to define types that are similar in structure, but differ in a parameter that could be an integer or could be something else. Is it possible in Java to define a family of classes para...

In C++20, I defined a concept AllIntegral with a non-type template parameter pack auto... T_values. Whilst, GCC 10.1.0 accepts its usage in some contexts, it refuses to compile its usage in others,...

I am learning concepts, and I can not figure out a way to restrain the value (not type) of non-type template parameter. Example of code that compiles, although I wish it did not(due to failed requi...

Concepts can be used to put a constraint on types as template parameters like the example below: template<typename t, int v> concept the_concept1 = sizeof(t) > v; template<int v, the_c...

I would like to use a template class to provide some common functionality to some child classes that are very similar. The only variation is the enumeration that each uses. This is the parent cla...

how would you go about using non-type template parameter comparison in a std::enable_if? I can not figure out how to do this again. (I once had this working, but I lost the code so I can't lo...

I understand that non-type template parameters should be a constant integral expression. Can someone shed light why this is so? template <std::string temp> void foo() { // ... } error C299...