How to know underlying type of class enum?

by

Since C++ 11 you can use this:

The doc says,

Defines a member typedef type of type that is the underlying type for the enumeration T.

So you should be able to do this:

#include <type_traits> //include this

FooEnum myEnum;
auto pointer = static_cast<std::underlying_type<FooEnum>::type*>(&myEnum);

In C++ 14 it has been a bit simplified (note there is no ::type):

auto pointer = static_cast<std::underlying_type_t<FooEnum>*>(&myEnum);

And finally since C++ 23 one can get value without explicit cast (docs):

auto value = std::to_underlying<FooEnum>(myEnum);

More Related Contents:

  1. C++ Need help for a homework program that reads in a list of doubles from a file and add a string to each double
  2. How to enforce move semantics when a vector grows?
  3. Is signed integer overflow still undefined behavior in C++?
  4. C++ lambda with captures as a function pointer
  5. using extern template (C++11)
  6. Move capture in lambda
  7. Will std::string always be null-terminated in C++11?
  8. SFINAE working in return type but not as template parameter
  9. Error “undefined reference to ‘std::cout'”
  10. When to use the brace-enclosed initializer?
  11. Constexpr Math Functions
  12. Is it possible to “store” a template parameter pack without expanding it?
  13. Allow for Range-Based For with enum classes?
  14. How to reverse the order of arguments of a variadic template function?
  15. Template specialization and enable_if problems [duplicate]
  16. Initializer-list-constructing a vector of noncopyable (but movable) objects
  17. A class name introduced inside a class is not treated as a nested class name
  18. What is the meaning of auto when using C++ trailing return type?
  19. Why is locking a std::mutex twice ‘Undefined Behaviour’?
  20. Why would I ever use push_back instead of emplace_back?
  21. How to compile C++ with C++11 support in Mac Terminal
  22. lvalue to rvalue implicit conversion
  23. constexpr not compiling in VC2013
  24. std::function and std::bind: what are they, and when should they be used?
  25. constexpr vs. static const: Which one to prefer?
  26. Understanding std::atomic::compare_exchange_weak() in C++11
  27. C++ Linker Error With Class static constexpr
  28. Does C++11 change the behavior of explicitly calling std::swap to ensure ADL-located swap’s are found, like boost::swap?
  29. How does “using std::swap” enable ADL?
  30. Is it safe to reinterpret_cast an enum class variable to a reference of the underlying type?

Leave a Comment