Function sbspace

freebsd/sys/sockbuf.h:227–243

* How much space is there in a socket buffer (so->so_snd or so->so_rcv)? * This is problematical if the fields are unsigned, as the space might * still be negative (ccc > hiwat or mbcnt > mbmax). */

 * still be negative (ccc > hiwat or mbcnt > mbmax).
 */
static inline long
sbspace(struct sockbuf *sb)
{
	int bleft, mleft;		/* size should match sockbuf fields */

#if 0
	SOCKBUF_LOCK_ASSERT(sb);
#endif

	if (sb->sb_flags & SB_STOP)
		return(0);

	bleft = sb->sb_hiwat - sb->sb_ccc;
	mleft = sb->sb_mbmax - sb->sb_mbcnt;

	return ((bleft < mleft) ? bleft : mleft);
}

#define SB_EMPTY_FIXUP(sb) do {						\
	if ((sb)->sb_mb == NULL) {					\