diff options
Diffstat (limited to 'include/acpi/actbl3.h')
| -rw-r--r-- | include/acpi/actbl3.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/include/acpi/actbl3.h b/include/acpi/actbl3.h index 37781ab806a5..8c61b5fe42a4 100644 --- a/include/acpi/actbl3.h +++ b/include/acpi/actbl3.h @@ -86,9 +86,15 @@ #pragma pack(1) /* - * Note about bitfields: The u8 type is used for bitfields in ACPI tables. - * This is the only type that is even remotely portable. Anything else is not - * portable, so do not use any other bitfield types. + * Note: C bitfields are not used for this reason: + * + * "Bitfields are great and easy to read, but unfortunately the C language + * does not specify the layout of bitfields in memory, which means they are + * essentially useless for dealing with packed data in on-disk formats or + * binary wire protocols." (Or ACPI tables and buffers.) "If you ask me, + * this decision was a design error in C. Ritchie could have picked an order + * and stuck with it." Norman Ramsey. + * See http://stackoverflow.com/a/1053662/41661 */ /******************************************************************************* |