[ruby-cvs:68743] shyouhei:r61560 (trunk): offsetof(type, foo.bar) is (arguably) a GCCism

shyouhei at ruby-lang.org shyouhei at ruby-lang.org
Tue Jan 2 15:41:57 JST 2018

shyouhei	2018-01-02 15:41:56 +0900 (Tue, 02 Jan 2018)

  New Revision: 61560


    offsetof(type, foo.bar) is (arguably) a GCCism
    TL;DR see http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2031.htm
    Suppose we have:
    struct X {
      struct Y {
        z_t z;
      } y;
    } x;
    then, you _cant_ infer offsetof(struct X, y.z). The ISO C99 section
    7.17 says nothing about such situation. At least clang warns this
    being an extension to the language (-Wextended-offsetof).

  Modified files:

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