#include  <stdio.h>

#ifdef DEBUG
#define CHECK(expr) foo(expr)
#else
#define CHECK(expr)
#endif /* DEBUG */

int bar (int x, int y, int z)
{
    //do nothing
    return 0;
}

int main(void)
{
    int a= 0, b = 0, c = 0;
    int x = bar(a, b, c); /* bar has to be called for both DEBUG begin defined and undefined */ 
    CHECK(x);
    printf("Hello, world!\n");
    return 0;
}