std::SignedIntegral (3) - Linux Man Pages
Defined in header <concepts>
template < class T > (since C++20)
concept SignedIntegral = std::Integral<T> && std::is_signed_v<T>;
The concept SignedIntegral<T> is satisfied if and only if T is an integral type and std::is_signed_v<T> is true.
SignedIntegral<T> may be satisfied by a type that is not a signed_integer_type, for example, char (on a system where char is signed).
is_integral checks if a type is an integral type
is_signed checks if a type is a signed arithmetic type