H5P: Property List Interface

Property List API Functions

The C Interfaces:

General Property List Operations H5Pcreate H5Pget_class H5Pcopy H5Pclose File Creation Properties H5Pget_version H5Pset_userblock H5Pget_userblock H5Pset_sizes H5Pget_sizes H5Pset_sym_k H5Pget_sym_k H5Pset_istore_k H5Pget_istore_k Variable-length Datatype Properties H5Pset_vlen_mem_manager H5Pget_vlen_mem_manager

File Access Properties xxx xxx xxx xxx xxx H5Pset_alignment H5Pget_alignment xxx xxx xxx   || xxx   || H5Pset_cache H5Pget_cache xxx xxx H5Pset_gc_references H5Pget_gc_references             ||  Available only in the parallel HDF5 library.

Dataset Creation Properties H5Pset_layout H5Pget_layout H5Pset_chunk H5Pget_chunk H5Pset_deflate H5Pset_fill_value H5Pget_fill_value H5Pset_filter H5Pget_nfilters H5Pget_filter H5Pset_external H5Pget_external_count H5Pget_external Dataset Memory and Transfer Properties H5Pset_buffer H5Pget_buffer H5Pset_preserve H5Pget_preserve H5Pset_hyper_cache H5Pget_hyper_cache H5Pset_btree_ratios H5Pget_btree_ratios xxx   || xxx   ||

The FORTRAN90 Interfaces:
In general, each FORTRAN90 subroutine performs exactly the same task as the corresponding C function. The links below go to the C function descriptions, which serve as general descriptions for both. A button, under Non-C API(s) at the end of the C function description, opens an external browser window displaying the FORTRAN90-specific information. You will probably want to adjust the size and location of this external window so that both browser windows are visible and to facilitate moving easily between them.

General Property List Operations h5pcreate_f h5pget_class_f h5pcopy_f h5pclose_f File Creation Properties h5pget_version_f h5pset_userblock_f h5pget_userblock_f h5pset_sizes_f h5pget_sizes_f h5pset_sym_k_f h5pget_sym_k_f h5pset_istore_k_f h5pget_istore_k_f

File Access Properties h5pget_driver_f h5pset_stdio_f h5pget_stdio_f h5pset_sec2_f h5pget_sec2_f h5pset_alignment_f h5pget_alignment_f h5pset_core_f h5pget_core_f h5pset_mpi_f   || h5pget_mpi_f   || h5pset_cache_f h5pget_cache_f h5pset_split_f h5pget_split_f h5pset_gc_references_f h5pget_gc_references_f   ||  Available only in the parallel HDF5 library.

Dataset Creation Properties h5pset_layout_f h5pget_layout_f h5pset_chunk_f h5pget_chunk_f h5pset_deflate_f h5pset_fill_value_f h5pget_fill_value_f h5pset_filter_f h5pget_filter_f h5pset_external_f h5pget_external_count_f h5pget_external_f Dataset Memory and Transfer Properties h5pset_hyper_cache_f h5pget_hyper_cache_f h5pset_btree_ratios_f h5pget_btree_ratios_f h5pset_xfer_f   || h5pget_xfer_f   ||

Name: H5Pcreate

Signature:

hid_t H5Pcreate(H5P_class_t type )

Purpose:

Creates a new property as an instance of a property list class.

Description:

H5Pcreate creates a new property as an instance of some property list class. The new property list is initialized with default values for the specified class. The classes are:

H5P_FILE_CREATE

Properties for file creation. See Files in the HDF User's Guide for details about the file creation properties.

H5P_FILE_ACCESS

Properties for file access. See Files in the HDF User's Guide for details about the file creation properties.

H5P_DATASET_CREATE

Properties for dataset creation. See Datasets in the HDF User's Guide for details about dataset creation properties.

H5P_DATASET_XFER

Properties for raw data transfer. See Datasets in the HDF User's Guide for details about raw data transfer properties.

H5P_MOUNT

Properties for file mounting. With this parameter, H5Pcreate creates and returns a new mount property list initialized with default values.

Parameters:

H5P_class_t type

IN: The type of property list to create.

Returns:

Returns a property list identifier (plist) if successful; otherwise Fail (-1).

Non-C API(s):

Name: H5Pclose

Signature:

herr_t H5Pclose(hid_t plist )

Purpose:

Terminates access to a property list.

Description:

H5Pclose terminates access to a property list. All property lists should be closed when the application is finished accessing them. This frees resources used by the property list.

Parameters:

hid_t plist

IN: Identifier of the property list to terminate access to.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_class

Signature:

H5P_class_t H5Pget_class(hid_t plist )

Purpose:

Returns the property list class for a property list.

Description:

H5Pget_class returns the property list class for the property list identified by the plist parameter. Valid property list classes are defined in the description of H5Pcreate().

Parameters:

hid_t plist

IN: Identifier of property list to query.

Returns:

Returns a property list class if successful. Otherwise returns H5P_NO_CLASS (-1).

Non-C API(s):

Name: H5Pcopy

Signature:

hid_t H5Pcopy(hid_t plist )

Purpose:

Copies an existing property list to create a new property list.

Description:

H5Pcopy copies an existing property list to create a new property list. The new property list has the same properties and values as the original property list.

Parameters:

hid_t plist

IN: Identifier of property list to duplicate.

Returns:

Returns a property list identifier if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_version

Signature:

herr_t H5Pget_version(hid_t plist, int * super, int * freelist, int * stab, int * shhdr )

Purpose:

Retrieves the version information of various objects for a file creation property list.

Description:

H5Pget_version retrieves the version information of various objects for a file creation property list. Any pointer parameters which are passed as NULL are not queried.

Parameters:

hid_t plist

IN: Identifier of the file creation property list.

int * super

OUT: Pointer to location to return super block version number.

int * freelist

OUT: Pointer to location to return global freelist version number.

int * stab

OUT: Pointer to location to return symbol table version number.

int * shhdr

OUT: Pointer to location to return shared object header version number.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_userblock

Signature:

herr_t H5Pset_userblock(hid_t plist, hsize_t size )

Purpose:

Sets user block size.

Description:

H5Pset_userblock sets the user block size of a file creation property list. The default user block size is 0; it may be set to any power of 2 equal to 512 or greater (512, 1024, 2048, etc.).

Parameters:

hid_t plist

IN: Identifier of property list to modify.

hsize_t size

IN: Size of the user-block in bytes.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_userblock

Signature:

herr_t H5Pget_userblock(hid_t plist, hsize_t * size )

Purpose:

Retrieves the size of a user block.

Description:

H5Pget_userblock retrieves the size of a user block in a file creation property list.

Parameters:

hid_t plist

IN: Identifier for property list to query.

hsize_t * size

OUT: Pointer to location to return user-block size.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_sizes

Signature:

herr_t H5Pset_sizes(hid_t plist, size_t sizeof_addr, size_t sizeof_size )

Purpose:

Sets the byte size of the offsets and lengths used to address objects in an HDF5 file.

Description:

H5Pset_sizes sets the byte size of the offsets and lengths used to address objects in an HDF5 file. This function is only valid for file creation property lists. Passing in a value of 0 for one of the sizeof parameters retains the current value. The default value for both values is 4 bytes. Valid values currently are 2, 4, 8 and 16.

Parameters:

hid_t plist

IN: Identifier of property list to modify.

size_t sizeof_addr

IN: Size of an object offset in bytes.

size_t sizeof_size

IN: Size of an object length in bytes.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_sizes

Signature:

herr_t H5Pget_sizes(hid_t plist, size_t * sizeof_addr, size_t * sizeof_size )

Purpose:

Retrieves the size of the offsets and lengths used in an HDF5 file.

Description:

H5Pget_sizes retrieves the size of the offsets and lengths used in an HDF5 file. This function is only valid for file creation property lists.

Parameters:

hid_t plist

IN: Identifier of property list to query.

size_t * size

OUT: Pointer to location to return offset size in bytes.

size_t * size

OUT: Pointer to location to return length size in bytes.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_sym_k

Signature:

herr_t H5Pset_sym_k(hid_t plist, int ik, int lk )

Purpose:

Sets the size of parameters used to control the symbol table nodes.

Description:

H5Pset_sym_k sets the size of parameters used to control the symbol table nodes. This function is only valid for file creation property lists. Passing in a value of 0 for one of the parameters retains the current value.

ik is one half the rank of a tree that stores a symbol table for a group. Internal nodes of the symbol table are on average 75% full. That is, the average rank of the tree is 1.5 times the value of ik.

lk is one half of the number of symbols that can be stored in a symbol table node. A symbol table node is the leaf of a symbol table tree which is used to store a group. When symbols are inserted randomly into a group, the group's symbol table nodes are 75% full on average. That is, they contain 1.5 times the number of symbols specified by lk.

Parameters:

hid_t plist

IN: Identifier for property list to query.

int ik

IN: Symbol table tree rank.

int lk

IN: Symbol table node size.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_sym_k

Signature:

herr_t H5Pget_sym_k(hid_t plist, int * ik, int * lk )

Purpose:

Retrieves the size of the symbol table B-tree 1/2 rank and the symbol table leaf node 1/2 size.

Description:

H5Pget_sym_k retrieves the size of the symbol table B-tree 1/2 rank and the symbol table leaf node 1/2 size. This function is only valid for file creation property lists. If a parameter valued is set to NULL, that parameter is not retrieved. See the description for H5Pset_sym_k for more information.

Parameters:

hid_t plist

IN: Property list to query.

int * ik

OUT: Pointer to location to return the symbol table's B-tree 1/2 rank.

int * size

OUT: Pointer to location to return the symbol table's leaf node 1/2 size.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_istore_k

Signature:

herr_t H5Pset_istore_k(hid_t plist, int ik )

Purpose:

Sets the size of the parameter used to control the B-trees for indexing chunked datasets.

Description:

H5Pset_istore_k sets the size of the parameter used to control the B-trees for indexing chunked datasets. This function is only valid for file creation property lists. Passing in a value of 0 for one of the parameters retains the current value.

ik is one half the rank of a tree that stores chunked raw data. On average, such a tree will be 75% full, or have an average rank of 1.5 times the value of ik.

Parameters:

hid_t plist

IN: Identifier of property list to query.

int ik

IN: 1/2 rank of chunked storage B-tree.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_istore_k

Signature:

herr_t H5Pget_istore_k(hid_t plist, int * ik )

Purpose:

Queries the 1/2 rank of an indexed storage B-tree.

Description:

H5Pget_istore_k queries the 1/2 rank of an indexed storage B-tree. The argument ik may be the null pointer (NULL). This function is only valid for file creation property lists.

See H5Pset_istore_k for details.

Parameters:

hid_t plist

IN: Identifier of property list to query.

int * ik

OUT: Pointer to location to return the chunked storage B-tree 1/2 rank.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_layout

Signature:

herr_t H5Pset_layout(hid_t plist, H5D_layout_t layout )

Purpose:

Sets the type of storage used store the raw data for a dataset.

Description:

H5Pset_layout sets the type of storage used store the raw data for a dataset. This function is only valid for dataset creation property lists. Valid parameters for layout are:

H5D_COMPACT    (Not yet implemented.)

Store raw data and object header contiguously in file. This should only be used for very small amounts of raw data (suggested less than 1KB).

H5D_CONTIGUOUS

Store raw data separately from object header in one large chunk in the file.

H5D_CHUNKED

Store raw data separately from object header in one large chunk in the file and store chunks of the raw data in separate locations in the file.

Parameters:

hid_t plist

IN: Identifier of property list to query.

H5D_layout_t layout

IN: Type of storage layout for raw data.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_layout

Signature:

H5D_layout_t H5Pget_layout(hid_t plist)

Purpose:

Returns the layout of the raw data for a dataset.

Description:

H5Pget_layout returns the layout of the raw data for a dataset. This function is only valid for dataset creation property lists. Valid types for layout are:

H5D_COMPACT    (Not yet implemented.)

Raw data and object header stored contiguously in file.

H5D_CONTIGUOUS

Raw data stored separately from object header in one large chunk in the file.

H5D_CHUNKED

Raw data stored separately from object header in chunks in separate locations in the file.

Parameters:

hid_t plist

IN: Identifier for property list to query.

Returns:

Returns the layout type of a a dataset creation property list if successful. Otherwise returns H5D_LAYOUT_ERROR (-1).

Non-C API(s):

Name: H5Pset_chunk

Signature:

herr_t H5Pset_chunk(hid_t plist, int ndims, const hsize_t * dim )

Purpose:

Sets the size of the chunks used to store a chunked layout dataset.

Description:

H5Pset_chunk sets the size of the chunks used to store a chunked layout dataset. This function is only valid for dataset creation property lists. The ndims parameter currently must be the same size as the rank of the dataset. The values of the dim array define the size of the chunks to store the dataset's raw data. As a side-effect, the layout of the dataset is changed to H5D_CHUNKED, if it is not already.

Parameters:

hid_t plist

IN: Identifier for property list to query.

int ndims

IN: The number of dimensions of each chunk.

const hsize_t * dim

IN: An array containing the size of each chunk.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_chunk

Signature:

int H5Pget_chunk(hid_t plist, int max_ndims, hsize_t * dims )

Purpose:

Retrieves the size of chunks for the raw data of a chunked layout dataset.

Description:

H5Pget_chunk retrieves the size of chunks for the raw data of a chunked layout dataset. This function is only valid for dataset creation property lists. At most, max_ndims elements of dims will be initialized.

Parameters:

hid_t plist

IN: Identifier of property list to query.

int max_ndims

IN: Size of the dims array.

hsize_t * dims

OUT: Array to store the chunk dimensions.

Returns:

Returns chunk dimensionality successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_alignment

Signature:

herr_t H5Pset_alignment(hid_t plist, hsize_t threshold, hsize_t alignment )

Purpose:

Sets alignment properties of a file access property list.

Description:

H5Pset_alignment sets the alignment properties of a file access property list so that any file object greater than or equal in size to threshold bytes will be aligned on an address which is a multiple of alignment. The addresses are relative to the end of the user block; the alignment is calculated by subtracting the user block size from the absolute file address and then adjusting the address to be a multiple of alignment.

Default values for threshold and alignment are one, implying no alignment. Generally the default values will result in the best performance for single-process access to the file. For MPI-IO and other parallel systems, choose an alignment which is a multiple of the disk block size.

Parameters:

hid_t plist

IN: Identifier for a file access property list.

hsize_t threshold

IN: Threshold value. Must be non-negative. Note that setting the threshold value to 0 (zero) has the effect of a special case, forcing everything to be aligned.

hsize_t alignment

IN: Alignment value. Must be a positive value.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_alignment

Signature:

herr_t H5Pget_alignment(hid_t plist, hsize_t *threshold, hsize_t *alignment )

Purpose:

Retrieves the current settings for alignment properties from a file access property list.

Description:

H5Pget_alignment retrieves the current settings for alignment properties from a file access property list. The threshold and/or alignment pointers may be null pointers (NULL).

Parameters:

hid_t plist

IN: Identifier of a file access property list.

hsize_t *threshold

OUT: Pointer to location of return threshold value.

hsize_t *alignment

OUT: Pointer to location of return alignment value.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_external

Signature:

herr_t H5Pset_external(hid_t plist, const char *name, off_t offset, hsize_t size )

Purpose:

Adds an external file to the list of external files.

Description:

H5Pset_external adds an external file to the list of external files.

If a dataset is split across multiple files then the files should be defined in order. The total size of the dataset is the sum of the size arguments for all the external files. If the total size is larger than the size of a dataset then the dataset can be extended (provided the data space also allows the extending).

The size argument specifies number of bytes reserved for data in the external file. If size is set to H5F_UNLIMITED, the external file can be of unlimited size and no more files can be added to the external files list.

Parameters:

hid_t plist

IN: Identifier of a dataset creation property list.

const char *name

IN: Name of an external file.

off_t offset

IN: Offset, in bytes, from the beginning of the file to the location in the file where the data starts.

hsize_t size

IN: Number of bytes reserved in the file for the data.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_external_count

Signature:

int H5Pget_external_count(hid_t plist )

Purpose:

Returns the number of external files for a dataset.

Description:

H5Pget_external_count returns the number of external files for the specified dataset.

Parameters:

hid_t plist

IN: Identifier of a dataset creation property list.

Returns:

Returns the number of external files if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_external

Signature:

herr_t H5Pget_external(hid_t plist, int idx, size_t name_size, char *name, off_t *offset, hsize_t *size )

Purpose:

Returns information about an external file.

Description:

H5Pget_external returns information about an external file. The external file is specified by its index, idx, which is a number from zero to N-1, where N is the value returned by H5Pget_external_count(). At most name_size characters are copied into the name array. If the external file name is longer than name_size with the null terminator, the return value is not null terminated (similar to strncpy()).

If name_size is zero or name is the null pointer, the external file name is not returned. If offset or size are null pointers then the corresponding information is not returned.

Parameters:

hid_t plist

IN: Identifier of a dataset creation property list.

int idx

IN: External file index.

size_t name_size

IN: Maximum length of name array.

char *name

OUT: Name of the external file.

off_t *offset

OUT: Pointer to a location to return an offset value.

hsize_t *size

OUT: Pointer to a location to return the size of the external file data.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_fill_value

Signature:

herr_t H5Pset_fill_value(hid_t plist_id, hid_t type_id, const void *value )

Purpose:

Sets a dataset fill value.

Description:

H5Pset_fill_value sets the fill value for a dataset creation property list.

The value is interpreted as being of type type_id. This need not be the same type as the dataset, but the library must be able to convert value to the dataset type when the dataset is created.

Notes:

If a fill value is set for a dataset (even if the fill value is all zeros), the fill value will be written to the file. If no fill value is set, then HDF5 relies on the underlying file driver (usually a Unix file system) to initialize unwritten parts of the file to zeros.

Creating a contiguous dataset with a fill value can be a very expensive operation since the optimization has not yet been implemented that would delay the writing of the fill values until after some data has been written.

Parameters:

hid_t plist_id

IN: Property list identifier.

hid_t type_id,

IN: The datatype identifier of value.

const void *value

IN: The fill value.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_fill_value

Signature:

herr_t H5Pget_fill_value(hid_t plist_id, hid_t type_id, void *value )

Purpose:

Retrieves a dataset fill value.

Description:

H5Pget_fill_value queries the fill value property of a dataset creation property list.

The fill value is returned through the value pointer.

Memory is allocated by the caller.

The fill value will be converted from its current data type to the type specified by type_id.

Parameters:

hid_t plist_id

IN: Property list identifier.

hid_t type_id,

IN: The datatype identifier of value.

const void *value

IN: The fill value.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_filter

Signature:

herr_t H5Pset_filter(hid_t plist, H5Z_filter_t filter, unsigned int flags, size_t cd_nelmts, const unsigned int cd_values[] )

Purpose:

Adds a filter to the filter pipeline.

Description:

H5Pset_filter adds the specified filter and corresponding properties to the end of an output filter pipeline. If plist is a dataset creation property list, the filter is added to the permanent filter pipeline; if plist is a dataset transfer property list, the filter is added to the transient filter pipeline.

The array cd_values contains cd_nelmts integers which are auxiliary data for the filter. The integer values will be stored in the dataset object header as part of the filter information.

The flags argument is a bit vector with the following fields specifying certain general properties of the filter:

H5Z_FLAG_OPTIONAL

If this bit is set then the filter is optional. If the filter fails (see below) during an H5Dwrite() operation then the filter is just excluded from the pipeline for the chunk for which it failed; the filter will not participate in the pipeline during an H5Dread() of the chunk. This is commonly used for compression filters: if the compression result would be larger than the input then the compression filter returns failure and the uncompressed data is stored in the file. If this bit is clear and a filter fails then H5Dwrite() or H5Dread() also fails.

Note:

This function currently supports only the permanent filter pipeline; plist_id must be a dataset creation property list.

Parameters:

hid_t plist

IN: Property list identifier.

H5Z_filter_t filter

IN: Filter to be added to the pipeline.

unsigned int flags

IN: Bit vector specifying certain general properties of the filter.

size_t cd_nelmts

IN: Number of elements in cd_values.

const unsigned int cd_values[]

IN: Auxiliary data for the filter.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_nfilters

Signature:

int H5Pget_nfilters(hid_t plist)

Purpose:

Returns the number of filters in the pipeline.

Description:

H5Pget_nfilters returns the number of filters defined in the filter pipeline associated with the property list plist.

In each pipeline, the filters are numbered from 0 through N-1, where N is the value returned by this function. During output to the file, the filters are applied in increasing order; during input from the file, they are applied in decreasing order.

H5Pget_nfilters returns the number of filters in the pipeline, including zero (0) if there are none.

Note:

This function currently supports only the permanent filter pipeline; plist_id must be a dataset creation property list.

Parameters:

hid_t plist

IN: Property list identifier.

Returns:

Returns the number of filters in the pipeline if successful; otherwise returns a negative value.

Name: H5Pget_filter

Signature:

H5Z_filter_t H5Pget_filter(hid_t plist, int filter_number, unsigned int *flags, size_t *cd_nelmts, unsigned int *cd_values, size_t namelen, char name[] )

Purpose:

Returns information about a filter in a pipeline.

Description:

H5Pget_filter returns information about a filter, specified by its filter number, in a filter pipeline, specified by the property list with which it is associated.

If plist is a dataset creation property list, the pipeline is a permanent filter pipeline; if plist is a dataset transfer property list, the pipeline is a transient filter pipeline.

On input, cd_nelmts indicates the number of entries in the cd_values array, as allocated by the caller; on return,cd_nelmts contains the number of values defined by the filter.

filter_number is a value between zero and N-1, as described in H5Pget_nfilters(). The function will return a negative value if the filter number is out of range.

If name is a pointer to an array of at least namelen bytes, the filter name will be copied into that array. The name will be null terminated if namelen is large enough. The filter name returned will be the name appearing in the file, the name registered for the filter, or an empty string.

The structure of the flags argument is discussed in H5Pset_filter().

Note:

This function currently supports only the permanent filter pipeline; plist must be a dataset creation property list.

Parameters:

hid_t plist

IN: Property list identifier.

int filter_number

IN: Sequence number within the filter pipeline of the filter for which information is sought.

unsigned int *flags

OUT: Bit vector specifying certain general properties of the filter.

size_t *cd_nelmts

IN/OUT: Number of elements in cd_values.

unsigned int *cd_values

OUT: Auxiliary data for the filter.

size_t namelen

IN: Anticipated number of characters in name.

char name[]

OUT: Name of the filter.

Returns:

Returns the filter identification number if successful. Otherwise returns H5Z_FILTER_ERROR (-1).

Non-C API(s):

Name: xxx

Signature:

xxx xxx(xxx xxx )

Purpose:

Description:

xxx

Parameters:

xxx xxx

IN:

OUT:

Returns:

Returns xxx if successful. Otherwise returns xxx.

Name: H5Pset_gc_references

Signature:

herr_t H5Pset_gc_reference(hid_t plist, unsigned gc_ref )

Purpose:

Sets garbage collecting references flag.

Description:

H5Pset_gc_references sets the flag for garbage collecting references for the file.

Dataset region references and other reference types use space in an HDF5 file's global heap. If garbage collection is on and the user passes in an uninitialized value in a reference structure, the heap might get corrupted. When garbage collection is off, however, and the user re-uses a reference, the previous heap block will be orphaned and not returned to the free heap space.

When garbage collection is on, the user must initialize the reference structures to 0 or risk heap corruption.

The default value for garbage collecting references is off.

Parameters:

hid_t plist

IN: File access property list identifier.

unsigned gc_ref

IN: Flag setting reference garbage collection to on (1) or off (0).

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_gc_references

Signature:

herr_t H5Pget_gc_references(hid_t plist, unsigned *gc_ref )

Purpose:

Returns garbage collecting references setting.

Description:

H5Pget_gc_references returns the current setting for the garbage collection references property from the specified file access property list. The garbage collection references property is set by H5Pset_gc_references.

Parameters:

hid_t plist

IN: File access property list identifier.

unsigned gc_ref

OUT: Flag returning the state of reference garbage collection. A returned value of 1 indicates that garbage collection is on while 0 indicates that garbage collection is off.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_cache

Signature:

herr_t H5Pset_cache(hid_t plist_id, int mdc_nelmts, int rdcc_nelmts, size_t rdcc_nbytes, double rdcc_w0 )

Purpose:

Sets the meta data cache and raw data chunk cache parameters.

Description:

H5Pset_cache sets the number of elements (objects) in the meta data cache and the number of elements, the total number of bytes, and the preemption policy value in the raw data chunk cache.

The plist_id is a file access property list. The number of elements (objects) in the meta data cache and the raw data chunk cache are mdc_nelmts and rdcc_nelmts, respectively. The total size of the raw data chunk cache and the preemption policy are rdcc_nbytes and rdcc_w0.

Any (or all) of the H5Pget_cache() pointer arguments may be null pointers.

The rdcc_w0 value should be between 0 and 1 inclusive and indicates how much chunks that have been fully read are favored for preemption. A value of zero means fully read chunks are treated no differently than other chunks (the preemption is strictly LRU) while a value of one means fully read chunks are always preempted before other chunks.

Parameters:

hid_t plist_id

IN: Identifier of the file access property list.

int mdc_nelmts

IN: Number of elements (objects) in the meta data cache.

int rdcc_nelmts

IN: Number of elements (objects) in the raw data chunk cache.

size_t rdcc_nbytes

IN: Total size of the raw data chunk cache, in bytes.

double rdcc_w0

IN: Preemption policy.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_cache

Signature:

herr_t H5Pget_cache(hid_t plist_id, int *mdc_nelmts, int *rdcc_nelmts, size_t *rdcc_nbytes, double *rdcc_w0 )

Purpose:

Queries the meta data cache and raw data chunk cache parameters.

Description:

H5Pget_cache retrieves the maximum possible number of elements in the meta data cache and raw data chunk cache, the maximum possible number of bytes in the raw data chunk cache, and the preemption policy value.

Any (or all) arguments may be null pointers, in which case the corresponding datum is not returned.

Parameters:

hid_t plist_id

IN: Identifier of the file access property list.

int *mdc_nelmts

IN/OUT: Number of elements (objects) in the meta data cache.

int *rdcc_nelmts

IN/OUT: Number of elements (objects) in the raw data chunk cache.

size_t *rdcc_nbytes

IN/OUT: Total size of the raw data chunk cache, in bytes.

double *rdcc_w0

IN/OUT: Preemption policy.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_hyper_cache

Signature:

herr_t H5Pset_hyper_cache(hid_t plist, unsigned cache, unsigned limit )

Purpose:

Indicates whether to cache hyperslab blocks during I/O.

Description:

Given a dataset transfer property list, H5Pset_hyper_cache indicates whether to cache hyperslab blocks during I/O, a process which can significantly increase I/O speeds.

When working with hyperslab selections, it is possible to significantly speed up I/O operations by retrieving an entire hyperslab from the file in one operation and caching it in memory. The cache parameter specifies whether to turn caching on for hyperslab I/O operations. If cache is set to 1, caching is turned on; if set to 0, caching is turned off.

The parameter limit sets the maximum size of the hyperslab block to cache. If a block is smaller than that limit, it may still not be cached if no memory is available. Setting limit to 0 (zero) indicates no limitation on the size of block to attempt to cache.

The default is to cache blocks with no limit on block size for serial I/O and to not cache blocks for parallel I/O.

Parameters:

hid_t plist

IN: Dataset transfer property list identifier.

unsigned cache

IN: A flag indicating whether caching is to be set to on (1) or off (0).

unsigned limit

IN: Maximum size of the hyperslab block to cache. 0 (zero) indicates no limit.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_hyper_cache

Signature:

herr_t H5Pget_hyper_cache(hid_t plist, unsigned *cache, unsigned *limit )

Purpose:

Returns information regarding the caching of hyperslab blocks during I/O.

Description:

Given a dataset transfer property list, H5Pget_hyper_cache returns instructions regarding the caching of hyperslab blocks during I/O. These parameters are set with the H5Pset_hyper_cache function.

Parameters:

hid_t plist

IN: Dataset transfer property list identifier.

unsigned *cache

OUT: A flag indicating whether caching is set to on (1) or off (0).

unsigned *limit

OUT: Maximum size of the hyperslab block to cache. 0 (zero) indicates no limit.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_btree_ratios

Signature:

herr_t H5Pset_btree_ratios(hid_t plist, double left, double middle, double right )

Purpose:

Sets B-tree split ratios for a dataset transfer property list.

Description:

H5Pset_btree_ratios sets the B-tree split ratios for a dataset transfer property list. The split ratios determine what percent of children go in the first node when a node splits.

The ratio left is used when the splitting node is the left-most node at its level in the tree; the ratio right is used when the splitting node is the right-most node at its level; and the ratio middle is used for all other cases.

A node which is the only node at its level in the tree uses the ratio right when it splits.

All ratios are real numbers between 0 and 1, inclusive.

Parameters:

hid_t plist

IN: The dataset transfer property list identifier.

double left

IN: The B-tree split ratio for left-most nodes.

double right

IN: The B-tree split ratio for right-most nodes and lone nodes.

double middle

IN: The B-tree split ratio for all other nodes.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pget_btree_ratios

Signature:

herr_t H5Pget_btree_ratios(hid_t plist, double *left, double *middle, double *right )

Purpose:

Gets B-tree split ratios for a dataset transfer property list.

Description:

H5Pget_btree_ratios returns the B-tree split ratios for a dataset transfer property list.

The B-tree split ratios are returned through the non-NULL arguments left, middle, and right, as set by the H5Pset_btree_ratios function.

Parameters:

hid_t plist

IN: The dataset transfer property list identifier.

double left

OUT: The B-tree split ratio for left-most nodes.

double right

OUT: The B-tree split ratio for right-most nodes and lone nodes.

double middle

OUT: The B-tree split ratio for all other nodes.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_buffer

Signature:

herr_t H5Pset_buffer(hid_t plist, size_t size, void *tconv, void *bkg )

Purpose:

Sets type conversion and background buffers.

Description:

Given a dataset transfer property list, H5Pset_buffer sets the maximum size for the type conversion buffer and background buffer and optionally supplies pointers to application-allocated buffers. If the buffer size is smaller than the entire amount of data being transferred between the application and the file, and a type conversion buffer or background buffer is required, then strip mining will be used.

Note that there are minimum size requirements for the buffer. Strip mining can only break the data up along the first dimension, so the buffer must be large enough to accommodate a complete slice that encompasses all of the remaining dimensions. For example, when strip mining a 100x200x300 hyperslab of a simple data space, the buffer must be large enough to hold 1x200x300 data elements. When strip mining a 100x200x300x150 hyperslab of a simple data space, the buffer must be large enough to hold 1x200x300x150 data elements.

If tconv and/or bkg are null pointers, then buffers will be allocated and freed during the data transfer.

The default value for the maximum buffer is 1 Mb.

Parameters:

hid_t plist

IN: Identifier for the dataset transfer property list.

size_t size

IN: Size, in bytes, of the type conversion and background buffers.

void tconv

IN: Pointer to application-allocated type conversion buffer.

void bkg

IN: Pointer to application-allocated background buffer.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Name: H5Pget_buffer

Signature:

size_t H5Pget_buffer(hid_t plist, void **tconv, void **bkg )

Purpose:

Reads buffer settings.

Description:

H5Pget_buffer reads values previously set with H5Pset_buffer().

Parameters:

hid_t plist

IN: Identifier for the dataset transfer property list.

void **tconv

OUT: Address of the pointer to application-allocated type conversion buffer.

void **bkg

OUT: Address of the pointer to application-allocated background buffer.

Returns:

Returns buffer size, in bytes, if successful; otherwise 0 on failure.

Name: H5Pset_preserve

Signature:

herr_t H5Pset_preserve(hid_t plist, hbool_t status )

Purpose:

Sets the dataset transfer property list status to TRUE or FALSE.

Description:

H5Pset_preserve sets the dataset transfer property list status to TRUE or FALSE.

When reading or writing compound data types and the destination is partially initialized and the read/write is intended to initialize the other members, one must set this property to TRUE. Otherwise the I/O pipeline treats the destination datapoints as completely uninitialized.

Parameters:

hid_t plist

IN: Identifier for the dataset transfer property list.

hbool_t status

IN: Status of for the dataset transfer property list (TRUE/FALSE).

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Name: H5Pget_preserve

Signature:

int H5Pget_preserve(hid_t plist)

Purpose:

Checks status of the dataset transfer property list.

Description:

H5Pget_preserve checks the status of the dataset transfer property list.

Parameters:

hid_t plist

IN: Identifier for the dataset transfer property list.

Returns:

Returns TRUE or FALSE if successful; otherwise returns a negative value.

Name: H5Pset_deflate

Signature:

herr_t H5Pset_deflate(hid_t plist, int level )

Purpose:

Sets compression method and compression level.

Description:

H5Pset_deflate sets the compression method for a dataset creation property list to H5D_COMPRESS_DEFLATE and the compression level to level, which should be a value from zero to nine, inclusive. Lower compression levels are faster but result in less compression. This is the same algorithm as used by the GNU gzip program.

Parameters:

hid_t plist

IN: Identifier for the dataset creation property list.

int level

IN: Compression level.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Non-C API(s):

Name: H5Pset_vlen_mem_manager

Signature:

herr_t H5Pset_vlen_mem_manager(hid_t plist, H5MM_allocate_t alloc, void *alloc_info, H5MM_free_t free, void *free_info )

Purpose:

Sets the memory manager for variable-length datatype allocation in H5Dread and H5Dvlen_reclaim.

Description:

H5Pset_vlen_mem_manager sets the memory manager for variable-length datatype allocation in H5Dread and free in H5Dvlen_reclaim.

The alloc and free parameters identify the memory management routines to be used. If the user has defined custom memory management routines, alloc and/or free should be set to make those routine calls (i.e., the name of the routine is used as the value of the parameter); if the user prefers to use the system's malloc and/or free, the alloc and free parameters, respectively, should be set to NULL

The prototypes for these user-defined functions would appear as follows:
     typedef void *(*H5MM_allocate_t)(size_t size, void *alloc_info) ;
     typedef void (*H5MM_free_t)(void *mem, void *free_info) ;
The alloc_info and free_info parameters can be used to pass along any required information to the user's memory management routines.

In summary, if the user has defined custom memory management routines, the name(s) of the routines are passed in the alloc and free parameters and the custom routines' parameters are passed in the alloc_info and free_info parameters. If the user wishes to use the system malloc and free functions, the alloc and/or free parameters are set to NULL and the alloc_info and free_info parameters are ignored.

Parameters:

hid_t plist

IN: Identifier for the dataset transfer property list.

H5MM_allocate_t alloc

IN: User's allocate routine, or   NULL for system   malloc.

void *alloc_info

IN: Extra parameter for user's allocation routine.
Contents are ignored if preceding parameter is   NULL.

H5MM_free_t free

IN: User's free routine, or   NULL for system free.

void *free_info

IN: Extra parameter for user's free routine.
Contents are ignored if preceding parameter is   NULL.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.

Name: H5Pget_vlen_mem_manager

Signature:

herr_t H5Pget_vlen_mem_manager(hid_t plist, H5MM_allocate_t *alloc, void **alloc_info, H5MM_free_t *free, void **free_info )

Purpose:

Gets the memory manager for variable-length datatype allocation in H5Dread and H5Dvlen_reclaim.

Description:

H5Pget_vlen_mem_manager is the companion function to H5Pset_vlen_mem_manager, returning the parameters set by that function.

Parameters:

hid_t plist

IN: Identifier for the dataset transfer property list.

H5MM_allocate_t alloc

OUT: User's allocate routine, or   NULL for system   malloc.

void *alloc_info

OUT: Extra parameter for user's allocation routine.
Contents are ignored if preceding parameter is   NULL.

H5MM_free_t free

OUT: User's free routine, or   NULL for system free.

void *free_info

OUT: Extra parameter for user's free routine.
Contents are ignored if preceding parameter is   NULL.

Returns:

Returns a non-negative value if successful; otherwise returns a negative value.