Unlimited Dimension

Contents:

How to Make an Array Appendable

To make an SDS array appendable, one dimension must be specified as unlimited when the array is created.

Following is how you would do this:

For example, if you took an example similar to the create example in the last section, and made it appendable, it might look as follows (this example also shows how to append data to the appendable array). You can either download the C or FORTRAN program at the end, or just take a look at the HTML version, with the HDF calls highlighted:

If you have downloaded this program, then you can compile and run it. It creates an HDF file called sdunl.hdf.

Contents of HDF Created

You can view the contents of the HDF file created, using the hdp command,
hdp dumpsds sdunl.hdf 
File name: sdunl.hdf 

Variable Name = data1
	 Index = 0
	 Type= 16-bit signed integer
	 Ref. = 2
	 Rank = 2
	 Number of attributes = 0
	 Dim0: Name=fakeDim0
		 Size = UNLIMITED (currently 11)
		 Type = number-type not set
		 Number of attributes = 0
	 Dim1: Name=fakeDim1
		 Size = 5
		 Type = number-type not set
		 Number of attributes = 0
	 Data : 
                1 2 3 4 5 
                2 3 4 5 6 
                3 4 5 6 7 
                4 5 6 7 8 
                5 6 7 8 9 
                6 7 8 9 10 
                7 8 9 10 11 
                8 9 10 11 12 
                9 10 11 12 13 
                10 11 12 13 14 
                1 2 3 4 5
If we had not appended data to this file, the Unlimited Dimension size would be 10, rather than 11, and the last line ("1 2 3 4 5") would not be there.

Download Sample Program (optional)

Programs used in this tutorial: [Compiling a program]