int puts(const char *);

​

// Users would expect sayHello() to work no matter where it is used...

#define sayHello() puts("Hello World!")

​

int main(void) {

    int puts = 0;

​

    // However, this will FAIL TO COMPILE.

    // This is because puts() has been shadowed by a local variable.

    sayHello();

​

    return 0;

}

​