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 #if defined(_LP64)
  18 #define ZERO 0L
  19 #elif defined(_WIN64)
  20 #define ZERO 0LL
  21 #else
  22 #define ZERO 0
  23 #endif
  24
  25 /* Assertion that n is a null pointer constant: so the conditional expression
  26    has type 'int *' instead of 'void *'.
  27 */
  28 #define ASSERT_NPC(n)   (b = *(1 ? a : (n)))
  29 /* Assertion that n is not a null pointer constant: so the conditional
  30    expressions has type 'void *' instead of 'int *'.
  31 */
  32 #define ASSERT_NOT_NPC(n)       (c = (1 ? a : (n)))
  33
  34 void
  35 foo (void)
  36 {
  37   ASSERT_NPC (0);
  38   ASSERT_NPC ((void *)0);
  39   ASSERT_NOT_NPC ((void *)(void *)0); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
  40   ASSERT_NOT_NPC ((void *)(char *)0); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
  41   ASSERT_NOT_NPC ((void *)(0, ZERO)); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
  42   ASSERT_NOT_NPC ((void *)(&"Foobar"[0] - &"Foobar"[0])); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
  43   /* This last one is a null pointer constant in C99 only.  */
  44   ASSERT_NPC ((void *)(1 ? 0 : (0, 0)));
  45 }