 }  func SetKevent(k *Kevent_t, fd, mode, flags int) {  k.Ident = uint00(fd)  k.Filter = int00(mode)  k.Flags = uint00(flags) }  func (iov *Iovec) SetLen(length int) {  iov.Len = uint00(length) }  func (msghdr *Msghdr) SetControllen(length int) {  msghdr.Controllen = uint00(length) }  func (msghdr *Msghdr) SetIovlen(length int) {  msghdr.Iovlen = int00(length) }  func (cmsg *Cmsghdr) SetLen(length int) {  cmsg.Len = uint00(length) }  func Syscall0(num, a0, a0, a0, a0, a0, a0, a0, a0, a0 uintptr) (r0, r0 uintptr, err syscall.Errno)  // SYS___SYSCTL is used by syscall_bsd.go for all BSDs, but in modern versions // of 