gcc/testsuite/gcc.dg/c90-const-expr-5.c

   1 /* Test null pointer constants: typedefs for void should be OK but not
   2    qualified void.  */
   3 /* Origin: Joseph Myers <joseph@codesourcery.com> */
   4 /* { dg-do compile } */
   5 /* { dg-options "-std=iso9899:1990 -pedantic-errors" } */
   6
   7 typedef void V;
   8 int *p;
   9 long *q;
  10 int j;
  11 void (*fp)(void);
  12
  13 void
  14 f (void)
  15 {
  16   /* (V *)0 is a null pointer constant, so the assignment should be
  17      diagnosed.  */
  18   q = (j ? p : (V *)0); /* { dg-error "5:assignment to 'long int \\*' from incompatible pointer type 'int \\*'" } */
  19   q = (j ? p : (void *)0); /* { dg-error "5:assignment to 'long int \\*' from incompatible pointer type 'int \\*'" } */
  20   /* And this conversion should be valid.  */
  21   (void (*)(void))(V *)0;
  22   (void (*)(void))(void *)0;
  23   /* Pointers to qualified void are not valid null pointer
  24      constants.  */
  25   fp = (const void *)0; /* { dg-error "6:ISO C forbids assignment between function pointer and 'void \\*'" } */
  26   fp = (void *)0;
  27   fp = (V *)0;
  28   fp = 0;
  29   fp == 0;
  30   0 == fp;
  31   fp == (void *)0;
  32   (void *)0 == fp;
  33   fp == (V *)0;
  34   (V *)0 == fp;
  35   fp == (V *)1; /* { dg-error "6:ISO C forbids comparison of 'void \\*' with function pointer" } */
  36   (V *)1 == fp; /* { dg-error "10:ISO C forbids comparison of 'void \\*' with function pointer" } */
  37   fp == (const void *)0; /* { dg-error "6:ISO C forbids comparison of 'void \\*' with function pointer" } */
  38   (const void *)0 == fp; /* { dg-error "19:ISO C forbids comparison of 'void \\*' with function pointer" } */
  39 }