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From: jgk@panix.com (Joe keane)
Newsgroups: comp.std.c
Subject: Re: Description of "." operator
Date: Sun, 9 Dec 2012 23:34:06 +0000 (UTC)
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In article <lntxrxnufa.fsf@nuthaus.mib.org>,
Keith Thompson  <kst-u@mib.org> wrote:
>N1570 6.5.2.3p3 says:
>
>    A postfix expression followed by the . operator and an identifier
>    designates a member of a structure or union object. The value
>    is that of the named member, and is an lvalue if the first
>    expression is an lvalue.
>
>Consider the use of the word "object" in the first sentence.
>
>An expression of struct type doesn't necessarily refer to an *object* of
>that type.  

Look up 'temporary lifetime' (6.2.4).

>For example:
>
>    struct pair { int x; int y; };
>    struct pair func(void) {
>        struct pair result = { 10, 20 };
>        return result;
>    }
>    ...
>    int y = func().y;

Change your code to:

    struct pair { int x; int y; char thisisbs[1]; };
    struct pair func(void) {
        struct pair result = { 10, 20 };
        return result;
    }
    ...
    int y = func().y;

to make it work.