#include <stdio.h>
void my_int_func(int x)
{
    printf( "%d\n", x );
}
 
int main()
{
    void (*foo)(int);
    enum( void (*)(int) ) { FF = &my_int_func }; 
    /* the ampersand is actually optional */
    foo = &my_int_func;
    foo(5);
    return 0;
}