ECC-1467: typename check in templates

src/grib_accessor_class_data_ccsds_packing.h

@@ -1,5 +1,7 @@
 #pragma once
+
 #include "grib_api_internal_cpp.h"
+#include <type_traits>
 
 #if defined(HAVE_LIBAEC) || defined(HAVE_AEC)
 #include <libaec.h>
@@ -42,6 +44,7 @@ public:
 template <typename T>
 int GribAccessorDataCcsdsPacking<T>::unpack(grib_accessor* a, T* val, size_t* len)
 {
+    static_assert(std::is_floating_point<T>::value, "Requires floating point numbers");
     grib_accessor_data_ccsds_packing* self = (grib_accessor_data_ccsds_packing*)a;
     grib_handle* hand = grib_handle_of_accessor(a);
 

src/grib_accessor_class_data_complex_packing.h

@@ -51,6 +51,7 @@ public:
 template <typename T>
 int GribAccessorClassDataComplexPacking<T>::unpack(grib_accessor* a, T* val, size_t* len)
 {
+    static_assert(std::is_floating_point<T>::value, "Requires floating point numbers");
     grib_accessor_data_complex_packing* self = (grib_accessor_data_complex_packing*)a;
     grib_handle* gh                          = grib_handle_of_accessor(a);
 

src/grib_accessor_class_data_g22order_packing.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "grib_api_internal.h"
+#include <type_traits>
 
 typedef struct grib_accessor_data_g22order_packing
 {
@@ -45,6 +46,7 @@ public:
 template <typename T>
 int GribAccessorDataG22orderPacking<T>::unpack(grib_accessor* a, T* val, size_t* len)
 {
+    static_assert(std::is_floating_point<T>::value, "Requires floating points numbers");
     grib_accessor_data_g22order_packing* self = (grib_accessor_data_g22order_packing*)a;
 
     size_t i    = 0;