prev_message
struct message *prev_message(struct message *);
for (mp = prev_message(dot); mp; mp = prev_message(mp)) {
for (mp = prev_message(dot); mp; mp = prev_message(mp))
for (mp = get_message(get_msgCount()); mp; mp = prev_message(mp))
mp = prev_message(mp);
struct message *prev_message(struct message *);