Last modified: 11 March 2013
Name: H5Pset_shared_mesg_phase_change
Signature:
  herr_t `H5Pset_shared_mesg_phase_change`( hid_t `fcpl_id`, unsigned `max_list`, unsigned `min_btree` )

Purpose:
  Sets shared object header message storage phase change thresholds.

Description:
  `H5Pset_shared_mesg_phase_change` sets 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 threshold value of `max_list`, storage switches to a B-tree 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 be created as B-trees and will never revert to lists.

  `fcpl_id` specifies the file creation property list.

Parameters:

  hid_t `fcpl_id` | IN: File creation property list identifier
  unsigned `max_list` | IN: Threshold above which storage of a shared object header message index shifts from list to B-tree
  unsigned `min_btree` | IN: 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.