__fpclassify
extern int __fpclassify(double value);
: sizeof(value) == sizeof(double) ? __fpclassify(value) \
extern int __fpclassify(double x);
return __fpclassify(value) > FP_INFINITE;
return __fpclassify(value) == FP_NAN;
return __fpclassify(value) == FP_INFINITE;
return __fpclassify(x);