Ambiguous call to abs

Question

I have a custom data type that in practice can be either float or double. On every OS except OSX, I am able to successfully build this C++11 templa

Answer 1

If you have many template functions causing this problem, you can use the following drop-in replacement:

#include 
#include 
#include 

namespace util {


template 
auto abs(T value) -> std::enable_if_t::value,
                                      T> { return value; }
template 
auto abs(T value) -> std::enable_if_t::value,
                                      T> { return std::fabs(value); }
template 
auto abs(T value) -> std::enable_if_t::value,
                                      T> { return std::abs(value); }
template 
auto abs(T value) -> std::enable_if_t::value,
                                      T> { return std::labs(value); }
template 
auto abs(T value) -> std::enable_if_t::value,
                                      T> { return std::llabs(value); }
template 
auto abs(T value) -> std::enable_if_t::value &&
                                          !std::is_floating_point::value &&
                                          !std::is_same::value &&
                                          !std::is_same::value &&
                                          !std::is_same::value,
                                      T> { return std::abs(value); }


} // namespace util

Just replace the std::abs calls with util::abs. (Needs c++11.)