Re: [Qemu-devel] [PATCH v2 04/14] qlit: remove compound literals

[Marc-André Lureau]

Hi

----- Original Message -----
> Marc-André Lureau <address@hidden> writes:
> 
> > They are not considered constant expressions in C, producing an error
> > when compiling a const QLit.
> 
> A const QLit?  Do you mean a non-const one?

Really a const QLitObject:


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[]) {
                                                                ^
Removing the "compound literals" fixes this error.

We may want to include it in the commit message, but I think it lacks a bit of 
"C standard" explanation. I think it is something like "compound literals" are 
not const. But then why does it work with (QLitObject[]) ? :)


> 
> > Signed-off-by: Marc-André Lureau <address@hidden>
> > ---
> >  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 a4ad91321b..f1d6eed317 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);
>