Programming

Using the MATLAB HDF Utility API

In addition to the standard HDF APIs, listed in Using HDF5 Data Type Objects, MATLAB supports utility functions that are designed to make using HDF in the MATLAB environment easier.

For example, the MATLAB HDF utility API includes a function, MLlistinfo, that you can use to view all types of open HDF identifiers, such as HDF SD file identifiers. MATLAB updates these lists whenever HDF identifiers are created or closed.

This code obtains a list of all open HDF file and data set identifiers, using the MLlistinfo function. In this example, only two identifiers are open:

• hdfml('listinfo')
  No open RI identifiers
  No open GR identifiers
  No open grid identifiers
  No open grid file identifiers
  No open annotation identifiers
  No open AN identifiers
  Open scientific dataset identifiers:
      262144
  Open scientific data file identifiers:
      393216
  No open Vdata identifiers
  No open Vgroup identifiers
  No open Vfile identifiers
  No open point identifiers
  No open point file identifiers
  No open swath identifiers
  No open swath file identifiers
  No open access identifiers
  No open file identifiers
  

Closing All Open HDF Identifiers

To close all open HDF identifiers in a single call, use the MLcloseall function. This call closes all open HDF identifiers:

• hdfml('closeall')
  

Example: Exporting Data to an HDF4 File

Using Low-Level File I/O Functions

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