Last modified: 2 May 2014
Name: H5Pget_core_write_tracking
Signature:
  `herr_t H5Pget_core_write_tracking(hid_t fapl_id, hbool_t *is_enabled, size_t *page_size)`
Purpose:
  Gets information about the write tracking feature used by the core VFD.
Description:
  When a file is created or opened for writing using the core virtual file driver (VFD) with the backing store option turned on, the VFD can be configured to track changes to the file and only write out the modified bytes. To avoid a large number of small writes, the changes can be aggregated into pages of a user-specified size. The core VFD is also known as the memory VFD. The driver identifier is `H5FD_CORE`.
Notes:
  This function is only for use with the core VFD and must be used after the call to `H5Pset_fapl_core`. It is an error to use this function with any other VFD.

  This function only applies to the backing store write operation which typically occurs when the file is flushed or closed. This function has no relationship to the increment parameter passed to `H5Pset_fapl_core`.

  For optimum performance, the `page_size` parameter should be a power of two.

Parameters:

  `hid_t fapl_id` | IN: File access property list identifier.
  `hbool_t *is_enabled` | OUT: Whether the feature is enabled.
  `size_t *page_size` | OUT: Size, in bytes, of write aggregation pages.

Returns:
  Returns a non-negative value if successful. Otherwise returns a negative value.
Fortran Interface:
  None
See Also:
  `H5Pset_core_write_tracking`
History:

  Release | Change
  1.8.13 | C function introduced with this release.