static const

static_const.c

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
  const int baz = rand();       // ok!
  baz = 99;                     // compile-time error.

  static int goo = rand();      // compile-time error.
  goo = 99;                     // ok.

  // So if we want a local variable to be "really constant," we really
  // do want to use "static const":

  static const int foo = 22;    // ok.
  static const int bar = rand();  // compile-time error.
}