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.