boost/libs/math/config/has_float128.cpp

//  Copyright John Maddock 2013.
//  Use, modification and distribution are subject to the
//  Boost Software License, Version 1.0. (See accompanying file
//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

extern "C" {
#include <quadmath.h>
}

int main()
{
   __float128 f = -2.0Q;
   f = fabsq(f);

   return 0;
}