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

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Mon, 27 Sep 2021 13:00:01 +0200

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 <[email-masked]>
>> ---
>>   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.

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.