Standard for union initialization?

[Kevin Martin]

In article <4930 at utzoo.UUCP> henry at utzoo.UUCP (Henry Spencer) asks:
>> Either way, this is less clear than an initializer of the form
>> 	element = value
>> e.g.
>> union {
>> 	<type1> foo;
>> 	<type2> bar;
>> 	<type3> mumble;
>> }baz = mumble = <initializer>;
>
>How do you use this to initialize a union inside a structure?


    struct foo {
        int bar;
        char *blech;
        union {
            float float_val;
            char char_val;
            long long_val;
        } onion;
    };

    struct foo x = {
        42,                     /* value for x.bar */
        "value for x.blech",
        char_val = 'x'          /* value for x.onion.char_val */
    };                          /* value for x */

-or- (adding full {}'s)
    struct foo x = {
        42,                     /* value for x.bar */
        "value for x.blech",
        {
            char_val = 'x'      /* value for x.onion.char_val */
        }                       /* value for x.onion */
    };                          /* value for x */


And, seeing as I see the next question coming...
>How do yo initialize a structure inside a union?
Well, this is where your YACC grammer may actually need changes (but this
applies to the name-the-type suggestion too...)

    union foo {
        int bar;
        char *blech;
        struct {
            float fred;
            char herbie;
            long harry;
        } stroct;
    };

    union foo x = {
        stroct = {
            4.2,                /* value for x.stroct.fred */
            'x',                /* value for x.stroct.herbie */
            0x12345678          /* value for x.stroct.harry */
        }                       /* value for x.stroct */
    };                          /* value for x */

-or- (removing extra {} )
    union foo x =
        stroct =
            4.2,                /* value for x.stroct.fred */
            'x',                /* value for x.stroct.herbie */
            0x12345678          /* value for x.stroct.harry */
    ;                           /* value for x */
(You would need the inner {} in this example, say, if you wanted
x.stroct.harry to be *implicitly* initialized to zero)

                        Kevin Martin, UofW Software Development Group