free and const

Question

C++ / C#

Faced with the following situation. There is a pointer (void *) which is subsequently freed via free()

struct {
  void *value;
  ....
};
...
// Присваивается указатель на какое-нибудь значение
node->value = value;
...
free(node->value);

The problem arises if node->value is assigned a pointer to a const variable (or string constant) that free() cannot clear.

Is it possible to check that a valid pointer is being passed to free() and prevent the problem? Or does it remain on the conscience of the pogromist?

Answer 1

void free(void * ptr);

but not

void free(const void * ptr);

Static typing checked for you.
It is not possible to disable the possibility of manual casting.

Answer 2

if node->value assign pointer to const variable

A normal compiler should swear at such an assignment.

Answer 3

No.

Answer 4

Clear. Thanks everyone for the replies.