> On Apr 30, 2024, at 15:52, Jason Merrill <ja...@redhat.com> wrote:
>
> On 4/30/24 14:49, Qing Zhao wrote:
>>> On Apr 30, 2024, at 15:45, Qing Zhao <qing.z...@oracle.com> wrote:
>>>
>>>
>>>
>>>>> gcc/doc/extend.texi | 34 ++++++++++++++++++++++++++++++++++
>>>>> 1 file changed, 34 insertions(+)
>>>>> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
>>>>> index 7b54a241a7bf..cba98c8aadd7 100644
>>>>> --- a/gcc/doc/extend.texi
>>>>> +++ b/gcc/doc/extend.texi
>>>>> @@ -42,6 +42,8 @@ extensions, accepted by GCC in C90 mode and in C++.
>>>>> * Named Address Spaces::Named address spaces.
>>>>> * Zero Length:: Zero-length arrays.
>>>>> * Empty Structures:: Structures with no members.
>>>>> +* Flexible Array Members in Unions:: Unions with Flexible Array Members.
>>>>> +* Flexible Array Members alone in Structures:: Structures with only
>>>>> Flexible Array Members.
>>>>> * Variable Length:: Arrays whose length is computed at run time.
>>>>> * Variadic Macros:: Macros with a variable number of arguments.
>>>>> * Escaped Newlines:: Slightly looser rules for escaped newlines.
>>>>> @@ -1873,6 +1875,38 @@ The structure has size zero. In C++, empty
>>>>> structures are part
>>>>> of the language. G++ treats empty structures as if they had a single
>>>>> member of type @code{char}.
>>>>> +@node Flexible Array Members in Unions
>>>>> +@section Unions with Flexible Array Members
>>>>> +@cindex unions with flexible array members
>>>>> +@cindex unions with FAMs
>>>>> +
>>>>> +GCC permits a C99 flexible array member (FAM) to be in a union:
>>>>> +
>>>>> +@smallexample
>>>>> +union with_fam @{
>>>>> + int a;
>>>>> + int b[];
>>>>> +@};
>>>>> +@end smallexample
>>>>> +
>>>>> +If all the members of a union are flexible array member, the size of
>>>
>>> It’s for the following case:
>>>
>>> union with_fam_3 {
>>> char a[];
>>> int b[];
>>> }
>>>
>>> And also include: (the only member of a union is a flexible array member
>>> as you mentioned below)
>>>
>>> union with_fam_1 {
>>> char a[];
>>> }
>>>
>>> So, I think the original sentence:
>>>
>>> “If all the members of a union are flexible array member, the size of”
>>>
>>> Should be better than the below:
>>>>
>>>> "If the only member of a union is a flexible array member”
>> How about the following wording?
>> "If every member of a union is flexible array member, the size of”
>
> "is a flexible array member", sure.
Okay, will update the doc.
Thanks a lot.
Qing
>
> Jason
>
