kern_sendmsg
error = kern_sendmsg(uap->s, NULL, &auio, NULL, 0, &tbytes);
error = kern_sendmsg(uap->s, sa, &auio, NULL, uap->flags,
error = kern_sendmsg(uap->s, sa, &auio, control, uap->flags,
int kern_sendmsg(int s, struct sockaddr *sa, struct uio *auio,