Re: [PATCH v3 5/7] qapi: Introduce QAPI_LIST_APPEND

[Eric Blake]

On 1/13/21 7:04 AM, Markus Armbruster wrote:
> Eric Blake <eblake@redhat.com> writes:
> 
>> Similar to the existing QAPI_LIST_PREPEND, but designed for use where
>> we want to preserve insertion order.  Callers will be added in
>> upcoming patches.  Note the difference in signature: PREPEND takes
>> List*, APPEND takes List**.
>>
>> Signed-off-by: Eric Blake <eblake@redhat.com>
>> ---
>>  include/qapi/util.h | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>
>> diff --git a/include/qapi/util.h b/include/qapi/util.h
>> index 6178e98e97a5..8b4967990c0d 100644
>> --- a/include/qapi/util.h
>> +++ b/include/qapi/util.h
>> @@ -37,4 +37,17 @@ int parse_qapi_name(const char *name, bool complete);
>>      (list) = _tmp; \
>>  } while (0)
>>
>> +/*
>> + * For any pointer to a GenericList @tail, insert @element at the back and
>> + * update the tail.
>> + *
>> + * Note that this macro evaluates @element exactly once, so it is safe
>> + * to have side-effects with that argument.
>> + */
>> +#define QAPI_LIST_APPEND(tail, element) do { \
>> +    *(tail) = g_malloc0(sizeof(**(tail))); \
>> +    (*(tail))->value = (element); \
>> +    (tail) = &(*tail)->next; \
>> +} while (0)
>> +
>>  #endif
> 
> You mentioned parenthesizing the lone unparenthesized occurence of
> @tail, like
> 
>   +    (tail) = &(*(tail))->next; \
> 
> Did you decide not to?

Hmm; not sure what happened. I still want the () added.  I'll respin
anyways, since my v3 crossed paths with what you already checked in.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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