Re: [9fans] Don't Plan 9 C compiler initialize the rest of member of a struct?

[Kyohei Kadota <lufia@lufia.org>]

Thank you for a reply.

I read spec on http://www.open-std.org/jtc1/sc22/WG14/www/docs/n1256.pdf
then I'm confusing.
This spec describes Initialization:

> 6.7.8 Initialization, p127
>
> 19 The initialization shall occur in initializer list order, each initializer provided for a
> particular subobject overriding any previously listed initializer for the same subobject;132)
> all subobjects that are not initialized explicitly shall be initialized implicitly the same as
> objects that have static storage duration.

What is "be initialized implicitly the same as objects that have
static storage duration" mean?

2019年4月2日(火) 9:27 Jeremy O'Brien <neutral@fastmail.com>:
>
> 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.
>