gcc/testsuite/gcc.dg/c90-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=iso9899:1990 -pedantic-errors -ftrack-macro-expansion=0" } */
   7
   8 struct s {
   9   int a;
  10 };
  11
  12 struct t {
  13   struct s a;
  14   int b[2];
  15 };
  16
  17 __extension__ typedef __SIZE_TYPE__ size_t;
  18 __extension__ typedef __UINTPTR_TYPE__ uintptr_t;
  19
  20 #define old_offsetof(TYPE, MEMBER) ((size_t) (uintptr_t) &((TYPE *)0)->MEMBER)
  21
  22 enum e {
  23   E1 = old_offsetof (struct s, a), /* { dg-error "constant" } */
  24   E2 = old_offsetof (struct t, a.a), /* { dg-error "constant" } */
  25   E3 = old_offsetof (struct t, b[1]), /* { dg-error "constant" } */
  26   E4 = __builtin_offsetof (struct s, a),
  27   E5 = __builtin_offsetof (struct t, a.a),
  28   E6 = __builtin_offsetof (struct t, b[1])
  29 };