Re: [PATCH v2 5/7] qapi: Introduce QAPI_LIST_APPEND

[Eric Blake]

On 11/17/20 6:51 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>

>> +#define QAPI_LIST_APPEND(tail, element) do { \
>> +    *(tail) = g_malloc0(sizeof(**(tail))); \
>> +    (*(tail))->value = (element); \
>> +    (tail) = &(*tail)->next; \

Hmm; I'm inconsistent on whether to spell things '*tail' or '*(tail)'.
I don't think any of the callers converted in patches 6 or 7 care about
the difference, but for maximal copy-paste portability, the use of the
macro parameter should be surrounded by () anywhere that could otherwise
cause a mis-parse on some arbitrary expression with an operator at
higher precedence than unary * (hmm, the only such operators are all
suffix operators; so maybe the *(tail) is overkill...)

> 
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org