std::make_unsigned(3)

NAME
std::make_unsigned - std::make_unsigned

Synopsis
   Defined in header <type_traits>
   template< class T > (since C++11)
   struct make_unsigned;
   If T is an integral (except bool) or enumeration type, provides the member typedef
   type which is the unsigned integer type corresponding to T, with the same
   cv-qualifiers.
   If T is signed or unsigned char, short, int, long, long long; the unsigned type from
   this list corresponding to T is provided.
   If T is an enumeration type or char, wchar_t
   , char8_t
   (since C++20), char16_t, char32_t; the unsigned integer type with the smallest rank
   having the same sizeof as T is provided.
   Otherwise, the behavior is undefined. (until C++20)
   Otherwise, the program is ill-formed. (since C++20)
   If the program adds specializations for std::make_unsigned, the behavior is
   undefined.

Member types
   Name Definition
   type the unsigned integer type corresponding to T

Helper types
   template< class T > (since C++14)
   using make_unsigned_t = typename make_unsigned<T>::type;

Example
// Run this code
 #include <type_traits>
 int main()
 {
     using uchar_type = std::make_unsigned_t<char>;
     using uint_type = std::make_unsigned_t<int>;
     using ulong_type = std::make_unsigned_t<volatile long>;
     static_assert(
         std::is_same_v<uchar_type, unsigned char> and
         std::is_same_v<uint_type, unsigned int> and
         std::is_same_v<ulong_type, volatile unsigned long>
     );
 }

See also
   is_signed checks if a type is a signed arithmetic type
   (C++11) (class template)
   is_unsigned checks if a type is an unsigned arithmetic type
   (C++11) (class template)
   make_signed makes the given integral type signed
   (C++11) (class template)