3004			This integral constant expression is being interpreted as a NULL pointer constant.
	Pointers				REFERENCE - ISO:C90-6.2.2.3 Pointers, ISO:C99-6.3.2.3 Pointers

• an integral constant expression with the value 0
• an integral constant expression with the value 0 cast to void *

/* PRQA S 1-9999 ++ */
/* PRQA S 3004 -- */

#define NULL (void *)0

void foo (void *);

void f3004 (void)
{
  char *p = NULL;          /* OK */
  p = 0;                   /* Message 3004 */

  if (p == 0) { }          /* Message 3004 */

  if (0 != p) { }          /* Message 3004 */

  foo (0);                 /* Message 3004 */
}