func New(bf *fmap.BlockFile) (*List, error) {
ctrl_a, err := bf.Allocate()
if err != nil {
return nil, err
}
data := make([]byte, 8)
moff := slice.AsUint64(&data)
*moff = ctrl_a
err = bf.SetControlData(data)
if err != nil {
return nil, err
}
return NewAt(bf, ctrl_a)
}
