HDF_SD_ATTRFIND

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.

Examples

; 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

IDL Output

TYPE STRING = 'STRING'

COUNT LONG = 8

NAME STRING = 'TITLE'

Syntax

Result = HDF_SD_ATTRFIND(SD_id, Name)

Arguments

SD_id

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”).

Name

A string containing the name of the attribute whose index is to be returned.

Keywords

None

Version History

4.0	Introduced