stdintegralconstant
std::integral_constant is a class template in the C++ standard library that represents a compile-time constant value as a type. It is defined as template<class T, T v> struct integral_constant { static constexpr T value = v; using value_type = T; using type = integral_constant; constexpr operator T() const noexcept { return value; } }; This construct makes a value available both as a type and as a value.
The primary purpose of std::integral_constant is to support type traits and template metaprogramming. It provides a
std::integral_constant is the base for a family of type wrappers such as std::true_type and std::false_type, which
In practice, std::integral_constant is used to convey constant information without runtime cost, to parameterize templates with