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Date: Mon, 20 Apr 2015 16:44:11 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Jiri Olsa <jolsa@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
        David Ahern <dsahern@gmail.com>
Subject: Re: [PATCH 3/7] perf tools: Move TUI-specific fields to struct
 hist_entry_tui
Message-ID: <20150420194411.GI11111@kernel.org>
References: <1429534850-13526-1-git-send-email-namhyung@kernel.org>
 <1429534850-13526-4-git-send-email-namhyung@kernel.org>
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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?

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