gcc/testsuite/gcc.dg/c99-const-expr-2.c

   1 /* Test for constant expressions: details of what is a null pointer
   2    constant.
   3 */
   4 /* Origin: Joseph Myers <jsm28@cam.ac.uk> */
   5 /* { dg-do compile } */
   6 /* { dg-options "-std=iso9899:1999" } */
   7 /* Note: not using -pedantic since the -std option alone should be enough
   8    to give the correct behavior to conforming programs.  If -pedantic is
   9    needed to make (say) (0, 0) not be a constant expression, this is a
  10    bug.
  11 */
  12
  13 int *a;
  14 int b;
  15 long *c;
  16
  17 /* Assertion that n is a null pointer constant: so the conditional expression
  18    has type 'int *' instead of 'void *'.
  19 */
  20 #define ASSERT_NPC(n)   (b = *(1 ? a : (n)))
  21 /* Assertion that n is not a null pointer constant: so the conditional
  22    expresions has type 'void *' instead of 'int *'.
  23 */
  24 #define ASSERT_NOT_NPC(n)       (c = (1 ? a : (n)))
  25
  26 void
  27 foo (void)
  28 {
  29   ASSERT_NPC (0);
  30   ASSERT_NPC ((void *)0);
  31   ASSERT_NOT_NPC ((void *)(void *)0); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */
  32   ASSERT_NOT_NPC ((void *)(char *)0); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */
  33   ASSERT_NOT_NPC ((void *)(0, 0)); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */
  34   /* This last one is a null pointer constant in C99 only.  */
  35   ASSERT_NPC ((void *)(1 ? 0 : (0, 0)));
  36 }