Previous Scientific Data Formats: Hierarchical Data Format Next

HDF_OPEN

Syntax | Return Value | Arguments | Keywords | Version History

The HDF_OPEN function opens or creates an HDF file for reading and/or writing.

Note that any combination of the READ, WRITE and CREATE keywords is valid.

Syntax

Result = HDF_OPEN( Filename [, /ALL] [, /CREATE] [, NUM_DD=value] [, /RDWR] [, /READ] [, /WRITE] )

Return Value

If successful, a non-zero file handle (a longword integer) is returned. Longword -1 is returned on failure.

Arguments

Filename

A scalar string containing the name of the file to be opened.

Keywords

ALL

Set this keyword to create a new HDF file with read and write access. Setting this keyword is equivalent to: 

HDF_OPEN(filename, /READ, /WRITE, /CREATE)

CREATE

Set this keyword to create a new HDF file.

NUM_DD

Use this keyword to override the machine default for the number of data descriptors to be allocated per DD block. For example: 

H = HDF_OPEN('foo.hdf',/CREATE,/WRITE, NUM_DD=100)

RDWR

Set this keyword to open file with both read and write access. Setting this keyword is equivalent to: 

HDF_OPEN(filename, /READ, /WRITE)

READ

Set this keyword to open the file with read access.

WRITE

Set this keyword to open the file with write access.

Version History

Pre 4.0
Introduced

  IDL Online Help (March 06, 2007)