- fd
- the FileDescriptor for the file you want to extract from.
- offset
- the offset into the file where the data to be extracted starts, in bytes
- length
- the length in bytes of the data to be extracted
Type Reason Java.IO.IOException
Sets the data source (FileDescriptor) to use. The FileDescriptor must be seekable (N.B. a LocalSocket is not seekable). It is the caller's responsibility to close the file descriptor. It is safe to do so as soon as this call returns.