On Jan 5 2017 15:34, Takashi Iwai wrote:
On Thu, 05 Jan 2017 01:41:31 +0100, Takashi Sakamoto wrote:
This reverts commit 6b7e95d1336b9eb0d4c6db190ce756480496bd13. This commit is based on a concern about value of the given parameter. It's expected to be ORed value with some enumeration-constants, thus often it can not be one of the enumeration-constants. I understood that this is out of specification and causes implementation-dependent issues.
In C language specification, enumerated type can be interpreted as an integer type, in which all of enumeration-constants in corresponding enumerator-list can be stored. Implementations can select one of char, signed int and unsigned int as its type, and this selection is implementation-dependent.
In GCC, a signed integer is selected when at least one of enumeration-constants has negative value, else an unsigned integer is selected. This behaviour can be switched by -fshort-enums to short type. Anyway, the type can be decided after scanning all of enumeration-constants.
Totally, there's no rules to constrain the value of enumerated type to be one of enumeration-constants. In short, in enumerated type, decision of actual type for the type is the most important and enumeration-constants are just used for the decision, thus it's permitted to have an integer value in a range of enumeration-constants. In our case, actual type for the type is currently deterministic to be either char or unsigned int. Under GCC, it's unsigned int.
You sign-off is missing.
Oops...
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp
Should I re-post this with the sign-off?
Thanks
Takashi Sakamoto