H5Iinc_ref increments the reference count of the object identified by
The reference count for an object ID is attached to the information about an object in memory and has no relation to the number of links to an object on disk.
The reference count for a newly created object will be 1. Reference counts for objects may be explicitly modified with this function or with
H5Idec_ref. When an object ID's reference count reaches zero, the object will be closed. Calling an object ID's 'close' function decrements the reference count for the ID which normally closes the object, but if the reference count for the ID has been incremented with this function, the object will only be closed when the reference count reaches zero with further calls to
H5Idec_ref or the object ID's 'close' function.
If the object ID was created by a collective parallel call (such as
H5Gopen, etc.), the reference count should be modified by all the processes which have copies of the ID. Generally this means that group, dataset, attribute, file and named datatype IDs should be modified by all the processes and that all other types of IDs are safe to modify by individual processes.
This function is of particular value when an application is maintaining multiple copies of an object ID. The object ID can be incremented when a copy is made. Each copy of the ID can then be safely closed or decremented and the HDF5 object will be closed when the reference count for that that object drops to zero.