Switch-case with pointers [duplicate]

Question

Possible Duplicate:
Why no switch on pointers?

int main(int argc, char** argv)
{
  void* not_a_pointer = 42;
  switch(not_a_pointer)
  {
    case 42:
      break;
  }

  return 0;
}

.

error: switch quantity not an integer

How can I portably use a switch-case for the value of a variable with a pointer type? The reason for this is that one of the callback functions in an API I'm using has a void* argument.

Answer 1

try casting to intptr_t, which is an integer type:

switch((intptr_t)not_a_pointer)

etc...