On Mon, Apr 20, 2015 at 04:44:11PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Apr 20, 2015 at 10:00:46PM +0900, Namhyung Kim escreveu:
> > +++ b/tools/perf/ui/browsers/hists.c
> > @@ -61,7 +61,7 @@ static int hist_browser__get_folding(struct hist_browser 
> > *browser)
> >                     rb_entry(nd, struct hist_entry, rb_node);
>   
> >             if (he->ms.unfolded)
> > -                   unfolded_rows += he->nr_rows;
> > +                   unfolded_rows += he->tui.nr_rows;
> 
> To avoid all these changes, I wonder if we can't use unamed structs in
> addition to the unnamed union?

But diff code uses named struct.  Does it support a mixed union
including named and unnamed members?

Hmm.. looks like it is.

#include <stdbool.h>
#include <stdio.h>

struct hist_entry {
        union {
                struct /* tui */ {
                        int nr_rows;
                        int row_offset;
                        /* other fields */
                };
                struct /* diff */ {
                        bool computed;
                        /* other fields */
                } diff;
        };
};

int main(int argc, char *argv[])
{
        struct hist_entry he = { .nr_rows = 11, .row_offset = 19, };
        
        printf("he.nr_rows=%d, he.row_offset=%d, he.diff.computed=%d\n",
                he.nr_rows, he.row_offset, he.diff.computed);
}

namhyung@sejong:tmp$ make mixed
cc     mixed.c   -o mixed
namhyung@sejong:tmp$ ./mixed
he.nr_rows=11, he.row_offset=19, he.diff.computed=11


OK, I'll change it to unnamed struct.

Thanks,
Namhyung


> 
> Like this what is done in include/net/sock.h, struct sock_common, and
> here:
> 
> [root@zoo ~]# cat unnamed_struct_union.c 
> #include <stdbool.h>
> #include <stdio.h>
> 
> struct hist_entry {
>       union {
>               struct /* tui */ {
>                       int nr_rows;
>                       int row_offset;
>                       /* other fields */
>               };
>               struct /* diff */ {
>                       bool computed;
>                       /* other fields */
>               };
>       };
> };
> 
> int main(int argc, char *argv[])
> {
>       struct hist_entry he = { .nr_rows = 11, .row_offset = 19, };
>       
>       printf("he.nr_rows=%d, he.row_offset=%d\n", he.nr_rows,
> he.row_offset);
> }
> [root@zoo ~]# make unnamed_struct_union
> cc     unnamed_struct_union.c   -o unnamed_struct_union
> [root@zoo ~]# ./unnamed_struct_union 
> he.nr_rows=11, he.row_offset=19
> [root@zoo ~]#
> 
> - Arnaldo
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