The HDF_SD_ATTRFIND function locates the index of an HDF attribute given its name. The attribute can be global or from a specific dataset. If an attribute is located, its index is returned. Otherwise, -1 is returned. Once an attribute’s index is known, the HDF_SD_ATTRINFO function can be used to read that attribute.
Result = HDF_SD_ATTRFIND(SD_id, Name)
An SD interface ID as returned by HDF_SD_START (i.e., a global attribute’s “SDinterface_id”), or HDF_SD_SELECT/HDF_SD_CREATE (i.e., a dataset’s “SDdataset_id”).
A string containing the name of the attribute whose index is to be returned.
None
; Open an HDF file and start the SD interface:
SDinterface_id = HDF_SD_START('demo.hdf')
; Find "TITLE", a global attribute:
gindex = HDF_SD_ATTRFIND(SDinterface_id, 'TITLE')
; Get the ID for the first dataset:
SDdataset_id = HDF_SD_SELECT(SDinterface_id, 1)
; Read attribute info:
HDF_SD_ATTRINFO,SDinterface_id,gindex, NAME=name, TYPE=type, COUNT=count
; Print info about the returned variables:
HELP, type, count, name
; Find the "LOCATION" dataset attribute:
dindex = HDF_SD_ATTRFIND(SDdataset_id, 'LOCATION')
; Read attribute info:
HDF_SD_ATTRINFO,SDdataset_id,dindex,NAME=name,TYPE=type,COUNT=count
TYPE STRING = 'STRING'
COUNT LONG = 8
NAME STRING = 'TITLE'
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4.0 |
Introduced |