On 8/10/09, Glenn Fowler <[email protected]> wrote:
>
>  here's a description of SEEK_HOLE and its companion SEEK_DATA
>
>        o  If whence is SEEK_HOLE, the offset of the start of  the
>           next  hole greater than or equal to the supplied offset
>           is returned. The definition of a hole is provided  near
>           the end of the DESCRIPTION.
>
>        o  If whence is SEEK_DATA, the file pointer is set to  the
>           start  of the next non-hole file region greater than or
>           equal to the supplied offset.
>
>  they are optimzations to aid in the discovery of holes on the read side
>  I believe the issue is not whether the ast code faithfully reproduces holes
>  when copying files (although the ast code may convert runs of 0's in real 
> data
>  to holes),

This conversion of 0's to holes is an actual problem for databases. A
hole in a file may reflect 'no records here' for a database while 0's
reflect that the record is valid and contains 0's as data.

Irek
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