Movatterモバイル変換

[Moved to DR at the November, 2014 meeting.]

Proposed resolution (February, 2014):

Change 9.13.2 [dcl.align] paragraph 5 as follows:

...if allalignment-specifiersappertaining to thatentity were omitted(including those in otherdeclarations).[Example:

  struct alignas(8) S {};  struct alignas(1) U {    S s;  };   // Error:U specifies an alignment that is less strict than       // if thealignas(1) were omitted.

—end example]

According to 9.13.2 [dcl.align] paragraph 5,

The combined effect of allalignment-specifiers in a declarationshall not specify an alignment that is less strict than the alignment thatwould be required for the entity being declared ifallalignment-specifiers were omitted (including those in otherdeclarations).

Presumably the intent was “other declarations of the sameentity,” but the wording as written could be read to make thefollowing example well-formed (assumingalignof(int) is 4):

  struct alignas(4) A {    alignas(8) int n;  };  struct alignas(8) B {    char c;  };  alignas(1) B b;  struct alignas(1) C : B {};  enum alignas(8) E : int { k };  alignas(4) E e = k;