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H5P_GET_CORE_WRITE_TRACKING

Gets information about the write tracking feature used by the core VFD

Procedure:

H5P_GET_CORE_WRITE_TRACKING ( fapl_id, is_enabled, page_size )

Signature:

herr_t H5Pget_core_write_tracking(hid_t 
    fapl_id, hbool_t *is_enabled, size_t 
    *page_size)

Parameters:
hid_t fapl_idIN: File access property list identifier
hbool_t *is_enabledOUT: Whether the feature is enabled
size_t *page_sizeOUT: Size, in bytes, of write aggregation pages

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.

This function is only for use with the core VFD and must be used after the call to H5P_SET_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 H5P_SET_FAPL_CORE.

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

 

Returns:

Returns a non-negative value if successful. Otherwise returns a negative value.

Example:

Coming Soon!

History:
ReleaseChange
1.8.13C function introduced with this release.

--- Last Modified: December 04, 2017 | 08:16 AM