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.

/*
 * Copy s2 to s1, truncating or null-padding to always copy n bytes
 * return s1
 */

char *
strncpy(s1, s2, n)
	register char *s1, *s2;
{
	register i;
	register char *os1;

	os1 = s1;
	for (i = 0; i < n; i++)
		if ((*s1++ = *s2++) == '\0') {
			while (++i < n)
				*s1++ = '\0';
			return(os1);
		}
	return(os1);
}