Synopsis

A literal pointer expression (like NULL) is dereferenced by a function call.

Enabled by default

No

Severity/Certainty

High/Medium

Full description

A literal pointer expression (for example NULL) is passed as argument to a function that might dereference it. Pointer values are generally only useful if acquired at runtime, and thus dereferencing a literal address is usually unintentional, resulting in corrupted memory or an application crash.

Coding standards

Code examples

The following code example fails the check and will give a warning:

#define NULL ((void *) 0)

extern int sometimes;

int bar(int *x){
  if (sometimes)
    *x = 3;
  return 0;
}

int foo(int *x) {
  bar(NULL);
}

The following code example passes the check and will not give a warning about this issue:

#define NULL ((void *) 0)

int bar(int *x){
  if (x != NULL)
    *x = 3;
  return 0;
}

int foo(int *x) {
  if (x != NULL) {
    *x = 4;
  }
  bar(x);
}