Code snippets:runonce func

From C

 #include <stdio.h>
 
 typedef int f_foo(int);
 
 f_foo foo_runonce;
 f_foo foo_runonce_done;
 f_foo * foo = foo_runonce;
 
 int main(void) {
     int i;
 
     i = 0;
     i += foo(42);
     i += foo(13);
     i += foo(4);
     printf("Total: %d\n", i);
     return 0;
   }
 
 int foo_runonce(int x) {
     printf("Run-once done!\n");
     foo = foo_runonce_done;
     return foo(x);
   }

 int foo_runonce_done(int x) {
     printf("%d\n", x);
     return x;
   }