so_set_asyncsigs
return (so_set_asyncsigs(vp, so->so_pgrp, events, 0, cr));
error = so_set_asyncsigs(vp, so->so_pgrp, events, mode, cr);
error = so_set_asyncsigs(vp, pgrp, events, mode, cr);
error = so_set_asyncsigs(vp, so->so_pgrp, 0, mode, cr);
extern int so_set_asyncsigs(vnode_t *, pid_t, int, int, cred_t *);