HDF_VG_ATTRGET

The HDF_VG_ATTRGET function retrieves the data within a VGroup's attribute.

Example

file = FILEPATH('vattr_example.hdf', SUBDIR=['examples', 'data'])

FileHandle = HDF_OPEN(file, /READ)

vgID = HDF_VG_GETID(FileHandle, -1)

VGroup = HDF_VG_ATTACH(FileHandle, vgID, /READ)

HDF_VG_GETINFO, VGroup, NAME=name, NATTRIBUTES=nattr

PRINT, name + '  number of attributes = ', nattr

; Find the attribute with the given name.

index = HDF_VG_ATTRFIND(VGroup, "MyAttributeSTRING")

; Determine the attribute info and value

HDF_VG_ATTRINFO, VGroup, index, COUNT=c, HDF_TYPE=hdfType, $

  NAME=attrname, SIZE=siz, TYPE=idlType

value = HDF_VG_ATTRGET(VGroup, index)

PRINT, attrname, ':  COUNT=', c.ToString(), $

  ' SIZE=', siz.ToString(), '  HDFtype=', hdfType, $

  '  IDLtype=', idlType, '  Value=', value

HDF_CLOSE,FileHandle

IDL prints:

RIG0.0  number of attributes =            8

MyAttributeSTRING:  COUNT=3 SIZE=3  HDFtype=DFNT_CHAR8  IDLtype=STRING  Value=ABC

Syntax

Result = HDF_VG_ATTRGET(VGroup, Index)

Return Value

Returns the specified attribute’s value.

Arguments

VGroup

The VGroup handle returned by a previous call to HDF_VG_ATTACH.

Index

The index of the attribute to retrieve. Index should be an integer in the range 0 to the number of attibutes minus 1. You can use HDF_VG_GETINFO to retrieve the number of attributes in the VGroup.

Keywords

None

Version History

8.5.1

Introduced