HDF_DFAN_GETFDS

The HDF_DFAN_GETFDS procedure reads the next available file description from an HDF file.

Syntax

HDF_DFAN_GETFDS, Filename, Description [, /FIRST] [, /STRING]

Arguments

Filename

A string containing the name of the file to be read.

Description

A named variable in which the description is returned. By default, the description is returned as a vector of bytes. Set the STRING keyword to return the description as a string.

If a description does not exist, the Description variable will contain either a 0L (long-integer zero) or a blank string, and a warning message will be printed. Warning messages can be suppressed by setting the !QUIET system variable to a non-zero value.

Keywords

FIRST

Set this keyword to read the first file description in the file. If FIRST is not set, the next available file description (which can be the first file description) will be read.

STRING

Set this keyword to return Description as a string instead of a vector of bytes.

Examples

filename = 'DEMOfds.hdf' 
fds1 = 'FILE DESCRIPTION NUMBER 1' 
fds2 = 'SHORT FDS 2' 
; Create an HDF file: 
fid = HDF_OPEN(filename, /CREATE) 
; Add first file description: 
HDF_DFAN_ADDFDS, filename, fds1 
; Add second file description: 
HDF_DFAN_ADDFDS, filename, fds2 
; Get the first file description: 
HDF_DFAN_GETFDS, filename, out_fds1, /FIRST 
HELP, out_fds1 
PRINT, STRING(out_fds1) 
; Get the second file description: 
HDF_DFAN_GETFDS, filename, out_fds2, /STRING 
HELP, out_fds2 
; Close the HDF file: 
HDF_CLOSE, fid

IDL Output

OUT_FDS1        BYTE      = Array(25) 
 
FILE DESCRIPTION NUMBER 1 
 
OUT_FDS2        STRING    = 'SHORT FDS 2'

Version History


4.0	Introduced