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Hseek
intn Hseek(int32
h_id
, int32
offset
, intn
origin
)
h_id
IN:
Access identifier returned by
Hstartread
,
Hstartwrite
, or
Hnextread
offset
IN:
Number of bytes to seek to from the origin
origin
IN:
Position of the offset origin
Purpose
Sets the access pointer to an offset within a data element.
Return value
Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.
Description
Sets the seek position for the next
Hread
or
Hwrite
operation by moving an access identifier to the specified position in a data element. The
origin
and the
offset
arguments determine the byte location for the access identifier. If
origin
is set to DF_START, the offset is added to the beginning of the data element. If
origin
is set to DF_CURRENT, the offset is added to the current position of the access identifier.
Valid values for
origin
are: DF_START (the beginning of the file) or DF_CURRENT (the current position in the file).
This routine fails if the access identifier if
h_id
is invalid or if the seek position is outside the range of the data element.
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HDF User's Reference Manual, Draft 06/09/97, NCSA HDF Development Group.