#ifdef foo
 #include <foo1.h>
#else
 #include <foo2.h>
#endif

#ifdef foo
/* Commentary for func1() */
void func1();

/* Commentary for func2() */
void func2();
#endif

int
show_interrupts(struct seq_file *p, void *v)
{
    #ifndef CONFIG_SMP
    a++;
    #else
    for (b = 0; b < 9; b++)
	if (b & 1)
	    k++;
    #endif

    if (v)
    {
	bar(v);
	#if DEBUG == 1
	printf("yup\n");
	#endif
    }
}

void foo()
{
    int i=0;
    #if DEBUG == 1
    i--;
    #endif
    i++;
}