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.
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