std::signed_integral(3)

NAME
std::signed_integral - std::signed_integral

Synopsis
   Defined in header <concepts>
   template< class T > (since C++20)
   concept signed_integral = std::integral<T> && std::is_signed_v<T>;
   The concept signed_integral<T> is satisfied if and only if T is an integral type and
   std::is_signed_v<T> is true.

Notes
   signed_integral<T> may be satisfied by a type that is not a signed integer type, for
   example, char (on a system where char is signed).

Example
// Run this code
 #include <concepts>
 #include <iostream>
 #include <string_view>
 void test(std::signed_integral auto x, std::string_view text = "")
 {
     std::cout << text << " (" + (text == "") << x << ") is a signed integral\n";
 }
 void test(std::unsigned_integral auto x, std::string_view text = "")
 {
     std::cout << text << " (" + (text == "") << x << ") is an unsigned integral\n";
 }
 void test(auto x, std::string_view text = "")
 {
     std::cout << text << " (" + (text == "") << x << ") is non-integral\n";
 }
 int main()
 {
     test(42); // signed
     test(0xFULL, "0xFULL"); // unsigned
     test('A'); // platform-dependent
     test(true, "true"); // unsigned
     test(4e-2, "4e-2"); // non-integral (hex-float)
     test("∫∫"); // non-integral
 }

Possible output:
 (42) is a signed integral
 0xFULL (15) is an unsigned integral
 (A) is a signed integral
 true (1) is an unsigned integral
 4e-2 (0.04) is non-integral
 (∫∫) is non-integral

See also
   is_integral checks if a type is an integral type
   (C++11) (class template)
   is_signed checks if a type is a signed arithmetic type
   (C++11) (class template)