Re: Don't Plan 9 C compiler initialize the rest of member of a struct?
Kyohei Kadota <[email protected]>
| Newsgroups | gmane.os.plan9.general |
|---|---|
| Message-ID | <CAFMepckUx1aMg48iw=eBXiVkxg_BvnbjqQqT9OVLTdhd=eSxaQ@mail.gmail.com> |
I see, I understand. thank you, Skip, Charles. 2019年4月3日(水) 0:06 Charles Forsyth <[email protected]>: > > >> What is "be initialized implicitly the same as objects that have >> static storage duration" mean? > > > It refers back to the second part of case 10 of that section. > > On Tue, 2 Apr 2019 at 15:53, Kyohei Kadota <[email protected]> wrote: >> >> 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 <[email protected]>: >> > >> > 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. >> > >>