socket_chgpgrp
extern int socket_chgpgrp(struct sonode *, pid_t);
error = (pid != so->so_pgrp) ? socket_chgpgrp(so, pid) : 0;
error = (pid != so->so_pgrp) ? socket_chgpgrp(so, pid) : 0;
error = (pid != so->so_pgrp) ? socket_chgpgrp(so, pid) : 0;