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SDreadchunk

intn SDreadchunk(int32 sds_id, int32 *origin, VOIDP datap)
sds_id

IN:

SD interface identifier returned from SDstart

origin

IN:

Origin of the chunk to be read

datap

OUT:

Buffer for the returned chunk data

Purpose

Reads data from a chunked scientific dataset.

Return value

Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.

Description

SDreadchunk is used when an entire chunk of data is to be read. SDreaddata is used when the read operation is to be done regardless of the chunking scheme used in the SDS.

Also, SDreadchunk is written specifically for chunked SDSs and and doesn't have the overhead of the additional functionality supported by the SDreaddata routine - therefore, it is much faster than SDreaddata.

SDreadchunk will return FAIL when an attempt is made to use it to read from a non-chunked SDS.



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HDF User's Reference Manual, Draft 06/09/97, NCSA HDF Development Group.