Specialization on signed types, C++ (clang)

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//Title of this code

#include <iostream>
#include <typeinfo>

template <typename T>
using EnableSigned = typename std::enable_if< std::is_signed<T>::value >::type* ;
template <typename T>
using EnableUnSigned = typename std::enable_if< std::is_unsigned<T>::value >::type* ;
template<class T , EnableSigned<T> = nullptr >
T myabs(T num) 
{
    return (num > 0) ? num : num*-1;
}
template<class T , EnableUnSigned<T> = nullptr >
T myabs(T num) 
{
    return num;
}

// the partial specialization of A is enabled via a template parameter
template<class T, class Enable = void>
class A {}; // primary template
 
template<class T>
class A<T, typename std::enable_if<std::is_signed<T>::value>::type> {
    public:
    A() {printf("Signed Value\n");}
    
}; // specialization for signed types

template<class T>
class A<T, typename std::enable_if<std::is_unsigned<T>::value>::type> {
    public:
    A() {printf("Unsigned Value\n");}
    
}; // specialization for unsigned types

int main()
{
    unsigned int  x = 90;
    int y = 100;
    A<int> myA;
    A<unsigned int> myB;
    
    printf("myabs = %d\n", myabs(x));
    printf("myabs = %d\n", myabs(y));
}

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Compilation time: 0.52 sec, absolute running time: 0.14 sec, cpu time: 0 sec, memory peak: 3 Mb, absolute service time: 0,66 sec