A quick test of a NoOverflow library

NoOverflow.cpp

#include <iostream>
#include <vector>
#include <limits>
#include <stdint.h>
#include <type_traits>

namespace NoOverflow{
    template <class T>
    using enable_if_unsigned_t = typename ::std::enable_if<std::is_unsigned<T>::value, T>::type;

    template <class T>
    using enable_if_signed_t = typename ::std::enable_if<std::is_signed<T>::value, T>::type;

    template<typename T> enable_if_unsigned_t<T> add(T a, T b){
        T res;
        if(__builtin_add_overflow(a, b, &res)){
            return std::numeric_limits<T>::max();
        }
        return res;
    }

    template<typename T> enable_if_signed_t<T> add(T a, T b){
        T res;
        if(__builtin_add_overflow(a, b, &res)){
            if(res<0)return std::numeric_limits<T>::max();
            else return std::numeric_limits<T>::min();
        }
        return res;
    }
};

int main()
{
    {
        uint16_t a = 1;
        uint16_t b = -1;
        a = 33000;
        b = 34000;
        std::cout << "16 bit overflow" << NoOverflow::add(a, b) << std::endl;
    }
    {
        int8_t a = 1;
        int8_t b = -1;
        a = -120;
        b = -120;
        std::cout << "8 bit overflow" << (int)NoOverflow::add(a, b) << std::endl;
    }
    {
        int8_t a = 1;
        int8_t b = -1;
        a = 120;
        b = 9;
        std::cout << "8 bit overflow" << (int)NoOverflow::add(a, b) << std::endl;
    }

    
    return 0;
}