How to make sure a function is only called once

Question

Suppose I have a function named caller, which will call a function named callee:

void caller()
{
    callee();
}  

Now caller might be called m

Answer 1

You could hide the function through a function pointer.

static void real_function()
{
  //do stuff

  function = noop_function;
}


static void noop_function()
{

}

int (*function)(void) = real_function;

Callers just call the function which will do the work the first time, and do nothing on any subsequent calls.