gcc/testsuite/gcc.dg/c99-const-expr-9.c

   1 /* Test for constant expressions: __builtin_offsetof allowed in
   2    integer constant expressions but not traditional offsetof
   3    expansion.  */
   4 /* Origin: Joseph Myers <joseph@codesourcery.com> */
   5 /* { dg-do compile } */
   6 /* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
   7
   8 struct s {
   9   int a;
  10 };
  11
  12 struct t {
  13   struct s a;
  14   int b[2];
  15 };
  16
  17 #define old_offsetof(TYPE, MEMBER) ((__SIZE_TYPE__) &((TYPE *)0)->MEMBER)
  18
  19 enum e {
  20   E1 = old_offsetof (struct s, a), /* { dg-error "constant" } */
  21   E2 = old_offsetof (struct t, a.a), /* { dg-error "constant" } */
  22   E3 = old_offsetof (struct t, b[1]), /* { dg-error "constant" } */
  23   E4 = __builtin_offsetof (struct s, a),
  24   E5 = __builtin_offsetof (struct t, a.a),
  25   E6 = __builtin_offsetof (struct t, b[1])
  26 };