-
-/* After you have called device_seek_file and/or device_seek_block,
- * you can start calling this function. It always reads exactly one whole
- * block at a time, however big that might be. You must pass in a buffer and
- * specify its size. If the buffer is big enough, the read is
- * performed, and both *size and the return value are equal to the
- * number of bytes actually read. If the buffer is not big enough, then
- * no read is performed, the function returns 0, and *size is set
- * to the minimum buffer size required to read the next block. If an
- * error occurs, the function returns -1 and *size is left unchanged.
- *
- * Note that this function may request a block size bigger than
- * dev->block_size, if it discovers an oversized block. This allows Amanda to
- * read from volumes regardless of the block size used to write them. It is not
- * an error if buffer == NULL and *size == 0. This should be treated as a query
- * as to the possible size of the next block, although it is not an error for
- * the next read to request an even larger block size. */