Last modified: 11 March 2013
Name: H5Pget_shared_mesg_phase_change
Signature:
herr_t H5Pget_shared_mesg_phase_change( hid_t fcpl_id, unsigned *max_list, unsigned *min_btree )

Purpose:
Retrieves shared object header message phase change information.

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.

Parameters:
hid_t fcpl_id IN: 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

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

Fortran90 Interface:
None.

History:
Release     C
1.8.0 Function introduced in this release.