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SubjectRe: [PATCH 3/7] perf tools: Move TUI-specific fields to struct hist_entry_tui
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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