Re: [PATCH 5/5] cbtree.h: define cb_init() in terms of CBTREE_INIT

[Phillip Wood <phillip.wood123@gmail.com>]

On 27/09/2021 12:00, Ævar Arnfjörð Bjarmason wrote:
> 
> On Mon, Sep 27 2021, Phillip Wood wrote:
> 
>> Hi Ævar
>>
>> On 27/09/2021 01:39, Ævar Arnfjörð Bjarmason wrote:
>>> Use the same pattern for cb_init() as the one established in the
>>> recent refactoring of other such patterns in
>>> 5726a6b4012 (*.c *_init(): define in terms of corresponding *_INIT
>>> macro, 2021-07-01).
>>> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
>>> ---
>>>    cbtree.h | 5 +++--
>>>    1 file changed, 3 insertions(+), 2 deletions(-)
>>> diff --git a/cbtree.h b/cbtree.h
>>> index a04a312c3f5..dedbb8e2a45 100644
>>> --- a/cbtree.h
>>> +++ b/cbtree.h
>>> @@ -37,11 +37,12 @@ enum cb_next {
>>>    	CB_BREAK = 1
>>>    };
>>>    -#define CBTREE_INIT { .root = NULL }
>>> +#define CBTREE_INIT { 0 }
>>>      static inline void cb_init(struct cb_tree *t)
>>>    {
>>> -	t->root = NULL;
>>> +	struct cb_tree blank = CBTREE_INIT;
>>> +	memcpy(t, &blank, sizeof(*t));
>>>    }
>>
>> Slightly off topic but would this be a good site for a compound
>> literal test balloon?
>>
>> 	*t = (struct cb_tree){ 0 };
>>
>> Compound literals are in C99 and seem to have been supported by MSVC
>> since 2013 [1].
> 
> I think that's a good thing to test out, FWIW I've also tested it on the
> IBM xlc, Oracle SunCC and HP/UX's aCC, they all seem to accept it.

Thanks for taking the time to test those other systems, it's good to 
know they support compound literals

> But I'd prefer just doing that in some general follow-up to bd4232fac33
> (Merge branch 'ab/struct-init', 2021-07-16), i.e. let's just use the
> init pattern it established here.

I agree it makes sense to introduce it as a separate series. I'm not 
sure if there is a pressing need for them but it is the sort of thing 
that is occasionally useful.

Best Wishes

Phillip