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std::is_unsigned(3)	      C++ Standard Libary	   std::is_unsigned(3)

NAME
       std::is_unsigned	- std::is_unsigned

Synopsis
	  Defined in header <type_traits>
	  template< class T >		   (since C++11)
	  struct is_unsigned;

	  std::is_unsigned is a	UnaryTypeTrait.

	  If T is an arithmetic	type, provides the member constant value equal
       to true if T(0)
	  < T(-1): this	results	in true	for the	unsigned integer types and the
       type bool and
	  in false for the signed integer types	and the	floating-point types.

	  For any other	type, value is false.

	  If   the   program  adds  specializations  for  std::is_unsigned  or
       std::is_unsigned_v, the
	  behavior is undefined.

Template parameters
	  T - a	type to	check

	  Helper variable template

	  template< class T >						(since
       C++17)
	  inline constexpr bool	is_unsigned_v =	is_unsigned<T>::value;

       Inherited from std::integral_constant

Member constants
	  value	   true	if T is	an unsigned integral type, false otherwise
	  [static] (public static member constant)

Member functions
	  operator bool	converts the object to bool, returns value
			(public	member function)
	  operator()	returns	value
	  (C++14)	(public	member function)

Member types
	  Type	     Definition
	  value_type bool
	  type	     std::integral_constant<bool, value>

Possible implementation
	  namespace detail
	  {
	      template<typename	T,bool = std::is_arithmetic<T>::value>
	      struct is_unsigned : std::integral_constant<bool,	T(0) <	T(-1)>
       {};

	      template<typename	T>
	      struct is_unsigned<T,false> : std::false_type {};
	  } // namespace detail

	  template<typename T>
	  struct is_unsigned : detail::is_unsigned<T>::type {};

Example
       // Run this code

	#include <iostream>
	#include <type_traits>

	class A	{};
	static_assert(std::is_unsigned_v<A> == false);

	enum B : unsigned {};
	static_assert(std::is_unsigned_v<B> == false);

	enum class C : unsigned	{};
	static_assert(std::is_unsigned_v<C> == false);

	struct S { unsigned p :	1; int q : 1; };
	static_assert(
	    std::is_unsigned_v<decltype(S::p)> not_eq
	    std::is_unsigned_v<decltype(S::q)>
	);

	static_assert(
	    std::is_unsigned_v<float> == false &&
	    std::is_unsigned_v<signed int> == false &&
	    std::is_unsigned_v<unsigned	int> ==	true &&
	    std::is_unsigned_v<bool> ==	true
	);

	int main()
	{
	    std::cout  <<  std::boolalpha  << std::is_unsigned<char>::value <<
       '\n';
	}

Possible output:
	false

See also
	  is_signed	checks if a type is a signed arithmetic	type
	  (C++11)	(class template)
	  is_signed	identifies signed types
	  [static]	(public	static member  constant	 of  std::numeric_lim-
       its<T>)
	  is_arithmetic	checks if a type is an arithmetic type
	  (C++11)	(class template)
	  make_signed	makes the given	integral type signed
	  (C++11)	(class template)
	  make_unsigned	makes the given	integral type unsigned
	  (C++11)	(class template)

http://cppreference.com		  2024.06.10		   std::is_unsigned(3)

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