--- eccodes-2.14.1-Source.unchanged/src/grib_api_prototypes.h	2019-10-10 13:33:52.000000000 +0200
+++ eccodes-2.14.1-Source/src/grib_api_prototypes.h	2019-10-27 11:20:05.496702520 +0100
@@ -872,8 +872,8 @@ double grib_ieeefloat_error(double x);
 double grib_long_to_ieee(unsigned long x);
 int grib_nearest_smaller_ieee_float(double a, double *x);
 unsigned long grib_ieee_to_long(double x);
-unsigned long grib_ieee64_to_long(double x);
-double grib_long_to_ieee64(unsigned long x);
+uint64_t grib_ieee64_to_long(double x);
+double grib_long_to_ieee64(uint64_t x);
 int grib_ieee_decode_array(grib_context *c, unsigned char *buf, size_t nvals, int bytes, double *val);
 int grib_ieee_decode_array(grib_context *c, unsigned char *buf, size_t nvals, int bytes, double *val);
 int grib_ieee_encode_array(grib_context *c, double *val, size_t nvals, int bytes, unsigned char *buf);
--- eccodes-2.14.1-Source.unchanged/src/grib_ieeefloat.c	2019-10-10 13:33:52.000000000 +0200
+++ eccodes-2.14.1-Source/src/grib_ieeefloat.c	2019-10-27 11:20:05.497702497 +0100
@@ -392,14 +392,14 @@ unsigned long grib_ieee_to_long(double x
  * grib_encode_unsigned_long.
  */
 
-unsigned long grib_ieee64_to_long(double x)
+uint64_t grib_ieee64_to_long(double x)
 {
     unsigned long lval;
     memcpy(&lval,&x,8);
     return lval;
 }
 
-double grib_long_to_ieee64 (unsigned long x)
+double grib_long_to_ieee64(uint64_t x)
 {
     double dval;
     memcpy(&dval,&x,8);