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H5P_GET_SHARED_MESG_PHASE_CHANGE

Retrieves shared object header message phase change information

Procedure:

H5P_GET_SHARED_MESG_PHASE_CHANGE ( fcpl_id, max_list, min_btree )

Signature:

herr_t H5Pget_shared_mesg_phase_change(
            hid_t fcpl_id,
            unsigned *max_list,
            unsigned *min_btree
    )

  

Parameters:
hid_t fcpl_idIN: File creation property list identifier
unsigned *max_list   OUT: Threshold above which storage of a shared object header message index shifts from list to B-tree
unsigned *min_btree    OUT: Threshold below which storage of a shared object header message index reverts to list format

Description:

H5Pget_shared_mesg_phase_change retrieves the threshold values for storage of shared object header message indexes in a file. These phase change thresholds determine the point at which the index storage mechanism changes from a more compact list format to a more performance-oriented B-tree format, and vice-versa.

By default, a shared object header message index is initially stored as a compact list. When the number of messages in an index exceeds the specified max_list threshold, storage switches to a B-tree format for improved performance. If the number of messages subsequently falls below the min_btree threshold, the index will revert to the list format.

If max_list is set to 0 (zero), shared object header message indexes in the file will always be stored as B-trees.

fcpl_id specifies the file creation property list.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Example:

Coming Soon!

History:
Release    C
1.8.0Function introduced in this release.

--- Last Modified: January 03, 2018 | 02:24 PM