Marc-André Lureau <marcandre.lur...@gmail.com> writes:
> Hi
>
> On Fri, Aug 25, 2017 at 8:20 AM Markus Armbruster <arm...@redhat.com> wrote:
>
>> Marc-André Lureau <marcandre.lur...@redhat.com> writes:
>>
>> > And misc code style fix.
>> >
>> > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
>> > ---
>> > include/qapi/qmp/qlit.h | 8 ++++----
>> > 1 file changed, 4 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/include/qapi/qmp/qlit.h b/include/qapi/qmp/qlit.h
>> > index f36bca4554..1e9696988a 100644
>> > --- a/include/qapi/qmp/qlit.h
>> > +++ b/include/qapi/qmp/qlit.h
>> > @@ -36,13 +36,13 @@ struct QLitDictEntry {
>> > };
>> >
>> > #define QLIT_QNUM(val) \
>> > - (QLitObject){.type = QTYPE_QNUM, .value.qnum = (val)}
>> > + { .type = QTYPE_QNUM, .value.qnum = (val) }
>> > #define QLIT_QSTR(val) \
>> > - (QLitObject){.type = QTYPE_QSTRING, .value.qstr = (val)}
>> > + { .type = QTYPE_QSTRING, .value.qstr = (val) }
>> > #define QLIT_QDICT(val) \
>> > - (QLitObject){.type = QTYPE_QDICT, .value.qdict = (val)}
>> > + { .type = QTYPE_QDICT, .value.qdict = (val) }
>> > #define QLIT_QLIST(val) \
>> > - (QLitObject){.type = QTYPE_QLIST, .value.qlist = (val)}
>> > + { .type = QTYPE_QLIST, .value.qlist = (val) }
>> >
>> > int compare_litqobj_to_qobj(QLitObject *lhs, QObject *rhs);
>>
>> Technically, this isn't a type cast, it's a compound literal. A
>> compound literal is "an unnamed object whose value is given by the
>> initializer list" (C99 §6.5.2.5). The standard then cautions "that this
>> differs from a cast expression" (ibid).
>
> You are right, but actually the patch helps with another issue if we keep
> the compound type:
>
> const QLitObject qmp_schema_qlit = QLIT_QLIST(((QLitObject[]) {
> QLIT_QNULL,
> {}
> }));
>
> qmp-introspect.c:17:63: error: initializer element is not constant
> const QLitObject qmp_schema_qlit = QLIT_QLIST(((QLitObject[]) {
> ^
> /home/elmarco/src/qemu/include/qapi/qmp/qlit.h:50:57: note: in definition
> of macro ‘QLIT_QLIST’
> (QLitObject) { .type = QTYPE_QLIST, .value.qlist = (val) }
> ^~~
> qmp-introspect.c:17:63: note: (near initialization for ‘(anonymous).value’)
> const QLitObject qmp_schema_qlit = QLIT_QLIST(((QLitObject[]) {
> ^
> /home/elmarco/src/qemu/include/qapi/qmp/qlit.h:50:57: note: in definition
> of macro ‘QLIT_QLIST’
> (QLitObject) { .type = QTYPE_QLIST, .value.qlist = (val) }
> ^~~
> Any idea how to fix that?
This one:
[...]
>> The original author's choice of compound literals is clearly
>> intentional. I'd prefer to respect it unless there's a compelling
>> reason not to.
Rewrite your commit message so it explains your *actual* reason for
converting the macro from compound literal to initializer.
