fcup-smsend[mult]: fix buglet in K&R C NULL pointer passing The only 100% safe way to pass a NULL pointer as a function argument in K&R C is to cast 0 to a pointer type; failing to do so may cause mysterious bugs (invalid stack frames or garbage in argument registers) on 64-bit machines. This issue has already been fixed in most of FC host tools, but I just found some missed spots: passing of NULL UDH to PDU encoding functions in fcup-smsend[mult] in the case of single (not concatenated) SMS.

/*
 * The structure defined in this header file is malloced in rvinterf
 * for every client program connection.
 */

#define	MAX_RVT_INTEREST	4

typedef	unsigned u32;

struct client {
	struct	client *next;
	int	fd;
	int	rx_state;
	u_char	rx_buf[LOCALSOCK_MAX_MSG];
	int	rx_msglen;
	u_char	*rx_ptr;
	int	rx_left;
	int	int_rvt_count;
	u32	int_rvt_mask[MAX_RVT_INTEREST];
	u32	int_rvt_match[MAX_RVT_INTEREST];
	char	int_proto[12];
};