From mboxrd@z Thu Jan  1 00:00:00 1970
User-Agent: Cyrus-JMAP/3.1.6-329-gf4aae99-fmstable-20190329v1
Mime-Version: 1.0
Message-Id: <43a5572d-ea50-41a8-9897-9900f13c5a00@www.fastmail.com>
In-Reply-To: <CAFMepcn3NR=phN=yp3Y0qeQ12jf40_Q_1krVZUm=2-bUCcMYOw@mail.gmail.com>
References: <CAFMepcn3NR=phN=yp3Y0qeQ12jf40_Q_1krVZUm=2-bUCcMYOw@mail.gmail.com>
Date: Mon,  1 Apr 2019 20:26:30 -0400
From: "Jeremy O'Brien" <neutral@fastmail.com>
To: 9fans@9fans.net
Content-Type: text/plain
Subject: Re: [9fans]
 =?utf-8?q?Don=27t_Plan_9_C_compiler_initialize_the_rest_o?=
 =?utf-8?q?f_member_of_a=09struct=3F?=
Topicbox-Message-UUID: f7ab570a-ead9-11e9-9d60-3106f5b1d025

On Mon, Apr 1, 2019, at 11:33, Kyohei Kadota wrote:
> Hi, 9fans. I use 9legacy.
>
> About below program, I expected that flags field will initialize to
> zero but the value of flags was a garbage, ex, "f8f7".
> Is this expected?
>
> ```
> #include <stdio.h>
>
> struct option {
>     int n;
>     char *s;
>     int flags;
> };
>
> int
> main(void)
> {
>     struct option opt = {1, "test"};
>     printf("%d %s %x\n", opt.n, opt.s, opt.flags);
>     return 0;
> }
> ```
>
>

According to C99: "If an object that has automatic storage duration is not initialized explicitly, its value is indeterminate."

Stack variable == automatic storage duration. This appears to be correct behavior to me.