diff options
Diffstat (limited to 'libsyscalls.h')
| -rw-r--r-- | libsyscalls.h | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/libsyscalls.h b/libsyscalls.h index 4c904b7..066de20 100644 --- a/libsyscalls.h +++ b/libsyscalls.h @@ -1129,8 +1129,9 @@ struct libsyscalls_datatype_description { enum libsyscalls_datatype_section section; /** - * This is a ~0 terminated array describing the order - * of the bytes the the data type + * This is a ~0 terminated array — but, it can also + * be terminated by the end of the array — describing + * the order of the bytes the the data type * * The lowest non-zero values contains the width of * a byte (in bytes), however no such value exists @@ -1146,8 +1147,17 @@ struct libsyscalls_datatype_description { * there is always a value in .byteorder that is 0, * unless .byteorder[0] is ~0 * - * To avoid problems checking for ~0, use - * the LIBSYSCALLS_IS_BYTEORDER_END macro + * To avoid problems checking for ~0, use the + * LIBSYSCALLS_IS_BYTEORDER_END macro; please also be + * aware that both the type and length can change in + * the future: do not assume it's `unsigned char`, + * and do not assume it has 32 elements, do not only + * `LIBSYSCALLS_IS_BYTEORDER_END` to detect ~0, but + * also check that no more than + * `sizeof(x.byteorder) / sizeof(*x.byteorder)` + * elements are read (where x is the instance of the + * structure) (you should definitely have your own + * macro for that one) */ unsigned char byteorder[32]; @@ -1160,8 +1170,13 @@ struct libsyscalls_datatype_description { * @param SHIFT The value to test `struct libsyscalls_datatype_description.byteorder` * @return :int Whether the value is ~0 */ -#define LIBSYSCALLS_IS_BYTEORDER_END(SHIFT)\ +#ifdef UINTMAX_C +# define LIBSYSCALLS_IS_BYTEORDER_END(SHIFT)\ + (!~((SHIFT) | ~LIBSYSCALLS_FIELD_MASK_(UINTMAX_C(1), struct libsyscalls_datatype_description, byteorder[0]))) +#else +# define LIBSYSCALLS_IS_BYTEORDER_END(SHIFT)\ (!~((SHIFT) | ~LIBSYSCALLS_FIELD_MASK_(1ULL, struct libsyscalls_datatype_description, byteorder[0]))) +#endif }; |