diff --git a/lib/bitutil.c b/lib/bitutil.c
index 9f71b59..aa000ff 100644
--- a/lib/bitutil.c
+++ b/lib/bitutil.c
@@ -27,6 +27,9 @@
 #pragma warning( disable : 4068)
 
 #include <math.h> //nan
+#define __STDC_WANT_IEC_60559_TYPES_EXT__
+#include <float.h> //_Float16
+
 #include "include_/conf.h"
 #include "include_/bitutil.h"
 
@@ -875,8 +878,7 @@ void bitzdec(unsigned char *in, unsigned n, unsigned esize) {
 }
 
 //----------- Lossy floating point conversion: pad the trailing mantissa bits with zero bits according to the relative error e (ex. 0.00001)  ----------
-
-  #ifndef _NFLOAT16
+  #ifdef FLT16_MAX
 // https://clang.llvm.org/docs/LanguageExtensions.html#half-precision-floating-point
 _Float16 _fprazor16(_Float16 d, float e, int lg2e) {
   uint16_t du = ctou16(&d), sign, u;