Examples of Macros that Fall under PRE00-C-EX5 and not PRE00-C-EX4

example_1.c

// The macro ADDRESS_OF reads the L-value of its argument x.
// If ADDRESS_OF were turned into a function, the L-value of
// its argument would change.
// Since it is a macro, this does not happen.
// Therefore, call-by-name semantics are required for ADDRESS_OF
// to function properly.
// This means ADDRESS_OF falls under EX5.
#define ADDRESS_OF(x) (&(x))

void foo()
{
    // ADDRESS_OF is only ever invoked with an argument of type int.
    // Therefore, ADDRESS_OF is not used to implement a generic function.
    // This means ADDRESS_OF does not fall under EX4.
    int x = 0;
    int y = 0;
    int z = 0;
    int *a = ADDRESS_OF(x);
    int *b = ADDRESS_OF(y);
    int *c = ADDRESS_OF(z);
}

example_2.c

struct node_t
{
    struct node_t *next;
};

// In this example, the macro CONNECT assigns the next member of
// the argument u to the address of the argument v
// CONNECT is not used polymorphically, so it does not fall under EX4.
// CONNECT only works correctly under call-by-name semantics, so it falls under EX5.
#define CONNECT(u, v) (((u)->next) = (&(v)))

void bar()
{
    struct node_t x, y, z;
    CONNECT(&x, y);
    CONNECT(&y, z);
    z.next = NULL;
}

example_3.c

#include <string.h>

#define CAP 32

struct person_t
{
    char name[CAP];
};

// Assigns the name field of a person_t pointer to the given name
void person_t_set_name(struct person_t *p, char *name)
{
    strncpy(p->name, name, CAP);
}

// SET_NAME is defined as an alias for person_t_set_name
// It is only ever invoked with the same types, so it does not fall under EX4.
// It does not behave the same under call-by-value semantics, so it falls under
// EX5.
#define SET_NAME(p, name) (person_t_set_name((&(p)), name))

void baz()
{
    struct person_t p, q, r;
    char name[CAP];

    strncpy(name, "Alpha", CAP);
    SET_NAME(p, name);

    strncpy(name, "Beta", CAP);
    SET_NAME(q, name);

    strncpy(name, "Gamma", CAP);
    SET_NAME(r, name);
}

Formatting on example 1.
Add example 2.

Wrap definition of CONNECT in example 2 in parentheses

Add example 3