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Re: [PATCH 1/2] Add constructor and destructor to thread_info
Pedro Alves <palves@redhat.com> writes:
>>> - struct target_waitstatus pending_follow;
>>> + struct target_waitstatus pending_follow {TARGET_WAITKIND_SPURIOUS};
>>>
>>
>> This will only initialize the first member of union
>> target_waitstatus.value to zero, so some bits of
>> target_waitstatus.value.related_pid is not initialized.
>
> Ah, blah, unions. Well, the result is that the remaining fields of
> the struct end up list->value->zero-initialized. Zero-initialization
> for unions means the first member is zero-initialized, and padding
> is initialized to zero. So I think the end result is the
> same anyway.
It is different from
"memset (&this->pending_follow, 0, sizeof (this->pending_follow))". The
first member "integer" is zero-initialized, but it is not the largest
member, so part of "related_pid" is not zero-initialized.
|<------------------ union----------------->|
|<------- related_pid ------->|<- padding ->|
|<- integer ->|
| 0 |<uninitialized>| 0 |
--
Yao (齐尧)