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What is a Property and Property List?
In HDF5, a property is a characteristic or feature associated with an HDF5 object. There are default properties which handle the most common needs. These default properties can be modified by use of the Property List interface and function parameters. You may recall that earlier it was mentioned that the default property was specified by passing in H5P_DEFAULT for the Property List parameter of the HDF5 calls.
The Property List API allows a user to take advantage of the more powerful features in HDF5. It typically supports unusual cases when creating or accessing HDF5 objects. There is a programming model for working with Property Lists in HDF5.
For an example of modifying a property list, see the tutorial topic Creating an Extendible Dataset. This example modifies the Dataset Creation Property List to use chunking for the dataset layout. (A contiguous dataset is created if the default layout is used when creating the dataset.)
There are many Property Lists associated with creating and accessing objects in HDF5. See the Property List Interface documentation in the HDF5 Reference Manual for a list of the different properties associated with HDF5 interfaces.
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In Summary:
Properties are features of HDF5 objects, that can be changed by use of the Property List API and function parameters. Property lists provide a mechanism for adding functionality to HDF5 calls without increasing the number of arguments used for a given call. The Property List API supports unusual cases when creating and accessing HDF5 objects. |
Programming Model
Default properties are specified by simply passing inH5P_DEFAULT (C) / H5P_DEFAULT_F (F90) for
the property list parameter in those functions for which
properties can be changed.
The programming model for changing a property list is as follows:
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Create a copy or "instance" of the desired pre-defined property type, using the H5Pcreate (C) / h5pcreate_f (F90) call. This will return a property list identifier. Please see the Reference Manual entry for H5Pcreate (C) / h5pcreate_f (F90), for a comprehensive list of the property types.
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With the property list identifier, modify the property, using the H5P APIs.
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Modify the object feature, by passing the property list identifier into the corresponding HDF5 object function.
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Close the property list when done, using H5Pclose (C) / h5pclose_f (F90).
- - Last modified:December 14th 2011