#define hexdigit(x) (((x) <= '9') ? (x) - '0' : ((x) & 7) + 9)
#define error_ptr(error) ((void*)error)
-#define is_error(ptr) ((unsigned long)ptr > (unsigned long)-4000L)
+#define error_description(error) (json_tokener_errors[error])
+#define is_error(ptr) (ptr == NULL)
#endif