Page History

...

HdfWriterNew also takes an optional fifth argument that users can use to clean up resources.  Since MyData is so simple, their there is no need to use this part of the API.  We will create the hdf5 type once, and not worry about closing it.  More complex types may make numerous subtypes along the way, that depend on the object.  If the hdf5 resources created are extensive, the user module will want to close hdf5 resources when they are no longer needed. The create function and optional fifth argument for closing would have to share a persistent structure that indexes these resources and closes them when they are no longer needed.

...