- Created by Mike McGreevy, last modified by Barbara Jones on May 28, 2019
H5Z_GET_FILTER_INFO
Retrieves information about a filter
Procedure:
H5Z_GET_FILTER_INFO (filter, filter_config)
Signature:
herr_t H5Zget_filter_info( H5Z_filter_t filter, unsigned int *filter_config )
SUBROUTINE h5zget_filter_info_f(filter, config_flags, hdferr)
IMPLICIT NONE
INTEGER, INTENT(IN) :: filter ! Filter, may be one of the
! following:
! H5Z_FILTER_DEFLATE_F
! H5Z_FILTER_SHUFFLE_F
! H5Z_FILTER_FLETCHER32_F
! H5Z_FILTER_SZIP_F
INTEGER, INTENT(OUT) :: config_flags ! Bit field indicating whether
! a filter's encoder and/or
! decoder are available
INTEGER, INTENT(OUT) :: hdferr ! Error code
END SUBROUTINE h5zfilter_avail_f
Parameters:
H5Z_filter_t filter | IN: Identifier of the filter to query. See the introduction to this section of the reference manual for a list of valid filter identifiers |
unsigned int *filter_config | OUT: A bit field encoding the returned filter information |
Description:
H5Z_GET_FILTER_INFO retrieves information about a filter. At present, this means that the function retrieves a filter's configuration flags, indicating whether the filter is configured to decode data, to encode data, neither, or both.
If filter_config is not set to NULL prior to the function call, the returned parameter contains a bit field specifying the available filter configuration. The configuration flag values can then be determined through a series of bitwise AND operations, as described below.
Valid filter configuration flags include the following:
H5Z_FILTER_CONFIG_ENCODE_ENABLED | Encoding is enabled for this filter In Fortran, H5Z_FILTER_ENCODE_ENABLED_F |
H5Z_FILTER_CONFIG_DECODE_ENABLED | Decoding is enabled for this filter In Fortran, H5Z_FILTER_DECODE_ENABLED_F |
(These flags are defined for C in the HDF5 library source code file H5Zpublic.h.) | |
A bitwise AND of the returned filter_config and a valid filter configuration flag will reveal whether the related configuration option is available. For example, if the value of H5Z_FILTER_CONFIG_ENCODE_ENABLED & filter_config
is true, i.e., greater than 0 (zero), the queried filter is configured to encode data; if the value is FALSE, i.e., equal to 0 (zero), the filter is not so configured.
If a filter is not encode-enabled, the corresponding H5Pset_* function will return an error if the filter is added to a dataset creation property list (which is required if the filter is to be used to encode that dataset). For example, if the H5Z_FILTER_CONFIG_ENCODE_ENABLED flag is not returned for the SZIP filter, H5Z_FILTER_SZIP, a call to H5P_SET_SZIP will fail.
If a filter is not decode-enabled, the application will not be able to read an existing file encoded with that filter.
This function should be called, and the returned filter_config analyzed, before calling any other function, such as H5P_SET_SZIP , that might require a particular filter configuration.
Returns:
Returns a non-negative value on success, a negative value on failure.
Example:
Coming Soon!
History:
| Release | Change |
|---|---|
| 1.6.3 | Function introduced in this release. Fortran subroutine introduced in this release. |
--- Last Modified: May 28, 2019 | 11:48 AM