• Obin@feddit.org
    20·
    2 days ago

    You mean ‘unnamed’ is what’s confusing you?

    Normally you can do anonymous struct/union members or struct struct/union members that are tagged structs but not anonymous.

    I.e. in standard C you’d have to do either:

    struct foo { int baz; };
struct bar { struct foo foo; };
...
struct bar data;
data.foo.baz = 0;

    or:

    struct bar { struct {  int baz; } foo; };
...
struct bar data;
data.baz = 0;

    but to do the following, you’d need the extension:

    struct foo { int baz; };
struct bar { struct foo; };
...
struct bar data;
data.baz = 0;
    • mina86@lemmy.wtfEnglish
      8·
      1 day ago

      Minor correction: Unnamed structs and unions (so your second example) are not part of C. They are GNU extensions.

      • MinekPo1 [it/she]@lemmygrad.ml
        3·
        2 days ago

        “ANSI C” by Kernighan and Ritchie disagrees , including that syntax (note : retranslation from Polish as that’s the language my copy is in) :

        A8.3

        […]

        struct-union-specifier:
        , union-struct identifier ₒₚₜ { compound-declaration-list }
        , union-struct identifier

        […]

        Specifiers of structures or unions with [a compound declaration] list, but with no label [identifier], creates a unique type; it may only be referred to in the declaration in which it is part.

        • mina86@lemmy.wtfEnglish
          1·
          1 day ago

          Yes, but I was talking about field name, not struct tag. And up to C99 my comment was correct.