On 25 February 2013 16:28, John Maddock wrote:
I haven't found one - gcc-4.7.2 has all sorts of __SIZEOF_XXX__ defines for every last type
*except*
__float128 and __float80 :-(
Sorry for a possibly stupid questio, but is it not possible to use any of the FLT128_XXX defines listed here:
http://gcc.gnu.org/onlinedocs/libquadmath/Typedef-and-constants.html#Typedef...
Including that header will only work (as in not generate a compiler error) if the compiler supports __float128 as a native type, which is what we want to work out... basically whether the GCC build was configured to support it or not.
The current libstdc++ headers define _GLIBCXX_USE_FLOAT128 if __float128 is supported, but that's an implementation detail and shouldn't be relied on (relying on _GLIBCXX_HAS_GTHREADS broke Boost.Threads recently when GCC 4.7 stopped defining it.)