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HDF5  1.14.4.3
API Reference
 
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References (H5R)

Detailed Description

Use the functions in this module to manage HDF5 references. Referents can be HDF5 objects, attributes, and selections on datasets a.k.a. dataset regions.

Macros

#define H5Rdereference   H5Rdereference2
 
#define H5Rget_obj_type   H5Rget_obj_type2
 

Functions

herr_t H5Rcreate_object (hid_t loc_id, const char *name, hid_t oapl_id, H5R_ref_t *ref_ptr)
 Creates an object reference.
 
herr_t H5Rcreate_region (hid_t loc_id, const char *name, hid_t space_id, hid_t oapl_id, H5R_ref_t *ref_ptr)
 Creates a region reference.
 
herr_t H5Rcreate_attr (hid_t loc_id, const char *name, const char *attr_name, hid_t oapl_id, H5R_ref_t *ref_ptr)
 Creates an attribute reference.
 
herr_t H5Rdestroy (H5R_ref_t *ref_ptr)
 Closes a reference.
 
H5R_type_t H5Rget_type (const H5R_ref_t *ref_ptr)
 Retrieves the type of a reference.
 
htri_t H5Requal (const H5R_ref_t *ref1_ptr, const H5R_ref_t *ref2_ptr)
 Determines whether two references are equal.
 
herr_t H5Rcopy (const H5R_ref_t *src_ref_ptr, H5R_ref_t *dst_ref_ptr)
 Copies an existing reference.
 
hid_t H5Ropen_object (H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t oapl_id)
 Opens the HDF5 object referenced.
 
hid_t H5Ropen_region (H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t oapl_id)
 Sets up a dataspace and selection as specified by a region reference.
 
hid_t H5Ropen_attr (H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t aapl_id)
 Opens the HDF5 attribute referenced.
 
herr_t H5Rget_obj_type3 (H5R_ref_t *ref_ptr, hid_t rapl_id, H5O_type_t *obj_type)
 Retrieves the type of object that an object reference points to.
 
ssize_t H5Rget_file_name (const H5R_ref_t *ref_ptr, char *name, size_t size)
 Retrieves the file name for a referenced object.
 
ssize_t H5Rget_obj_name (H5R_ref_t *ref_ptr, hid_t rapl_id, char *name, size_t size)
 Retrieves the object name for a referenced object.
 
ssize_t H5Rget_attr_name (const H5R_ref_t *ref_ptr, char *name, size_t size)
 Retrieves the attribute name for a referenced object.
 
H5G_obj_t H5Rget_obj_type1 (hid_t id, H5R_type_t ref_type, const void *ref)
 Retrieves the type of object that an object reference points to.
 
hid_t H5Rdereference1 (hid_t obj_id, H5R_type_t ref_type, const void *ref)
 Opens the HDF5 object referenced.
 
herr_t H5Rcreate (void *ref, hid_t loc_id, const char *name, H5R_type_t ref_type, hid_t space_id)
 Creates a reference.
 
herr_t H5Rget_obj_type2 (hid_t id, H5R_type_t ref_type, const void *ref, H5O_type_t *obj_type)
 Retrieves the type of object that an object reference points to.
 
hid_t H5Rdereference2 (hid_t obj_id, hid_t oapl_id, H5R_type_t ref_type, const void *ref)
 Opens the HDF5 object referenced.
 
hid_t H5Rget_region (hid_t dataset, H5R_type_t ref_type, const void *ref)
 Sets up a dataspace and selection as specified by a region reference.
 
ssize_t H5Rget_name (hid_t loc_id, H5R_type_t ref_type, const void *ref, char *name, size_t size)
 Retrieves a name for a referenced object.
 

Macro Definition Documentation

◆ H5Rdereference

#define H5Rdereference   H5Rdereference2

H5Rdereference() is a macro that is mapped to either H5Rdereference1() or H5Rdereference2().

See also
API Compatibility Macros

◆ H5Rget_obj_type

#define H5Rget_obj_type   H5Rget_obj_type2

H5Rget_obj_type() is a macro that is mapped to either H5Rget_obj_type1() or H5Rget_obj_type2() or H5R_get_obj_type3().

See also
API Compatibility Macros

Function Documentation

◆ H5Rcopy()

herr_t H5Rcopy ( const H5R_ref_t src_ref_ptr,
H5R_ref_t dst_ref_ptr 
)

Copies an existing reference.


Parameters
[in]src_ref_ptrPointer to reference to copy
[out]dst_ref_ptrPointer to output reference
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

H5Rcopy() creates a copy of an existing reference. src_ref_ptr points to the reference to copy, and dst_ref_ptr is the pointer to the destination reference.

Since
1.12.0

◆ H5Rcreate()

herr_t H5Rcreate ( void *  ref,
hid_t  loc_id,
const char *  name,
H5R_type_t  ref_type,
hid_t  space_id 
)

Creates a reference.


Parameters
[out]refReference created by the function call
[in]loc_idLocation identifier used to locate the object being pointed to
[in]nameName of object at location loc_id
[in]ref_typeType of reference
[in]space_idDataspace identifier with selection. Used only for dataset region references; pass as -1 if reference is an object reference, i.e., of type H5R_OBJECT
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

H5Rcreate() creates the reference, ref, of the type specified in ref_type, pointing to the object name located at loc_id.

The HDF5 library maps the void type specified above for ref to the type specified in ref_type, which will be one of the following:

typedef enum {
H5R_BADTYPE = (-1),
H5R_ATTR = 4,
H5R_type_t
Definition H5Rpublic.h:51
@ H5R_DATASET_REGION2
Definition H5Rpublic.h:56
@ H5R_BADTYPE
Definition H5Rpublic.h:52
@ H5R_OBJECT2
Definition H5Rpublic.h:55
@ H5R_MAXTYPE
Definition H5Rpublic.h:58
@ H5R_DATASET_REGION1
Definition H5Rpublic.h:54
@ H5R_OBJECT1
Definition H5Rpublic.h:53
@ H5R_ATTR
Definition H5Rpublic.h:57

The parameters loc_id and name are used to locate the object.

The parameter space_id identifies the dataset region that a dataset region reference points to. This parameter is used only with dataset region references and should be set to -1 if the reference is an object reference, H5R_OBJECT.

Since
1.0.0

◆ H5Rcreate_attr()

herr_t H5Rcreate_attr ( hid_t  loc_id,
const char *  name,
const char *  attr_name,
hid_t  oapl_id,
H5R_ref_t ref_ptr 
)

Creates an attribute reference.


Parameters
[in]loc_idLocation identifier. The identifier may be that of a file, group, dataset, named datatype, or attribute.
[in]nameName of object
[in]attr_nameName of attribute
[in]oapl_idObject access property list identifier
[out]ref_ptrPointer to reference
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

H5Rcreate_attr() creates the reference, ref_ptr, pointing to the attribute named attr_name and attached to the object named name located at loc_id.

The parameters loc_id and name locate the object. The parameter attr_name specifies the attribute within the object.

The parameter oapl_id is an object access property list identifier for the object that the referenced attribute is attached to. The access property list must be of the same type as that object, that is a group, dataset or committed datatype property list.

H5R_ref_t is defined in H5Rpublic.h as:

typedef struct {
union {
uint8_t __data[H5R_REF_BUF_SIZE];
int64_t align;
} u;
#define H5R_REF_BUF_SIZE
Definition H5Rpublic.h:38
Definition H5Rpublic.h:97

H5Rdestroy() should be used to release the resource from the reference.

Since
1.12.0

◆ H5Rcreate_object()

herr_t H5Rcreate_object ( hid_t  loc_id,
const char *  name,
hid_t  oapl_id,
H5R_ref_t ref_ptr 
)

Creates an object reference.


Parameters
[in]loc_idLocation identifier. The identifier may be that of a file, group, dataset, named datatype, or attribute.
[in]nameName of object
[in]oapl_idObject access property list identifier
[out]ref_ptrPointer to reference
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

H5Rcreate_object() creates a reference pointing to the object named name located at loc_id. The parameters loc_id and name are used to locate the object.

The parameter oapl_id is an object access property list identifier for the referenced object. The access property list must be of the same type as the object being referenced, that is a group, dataset or committed datatype property list.

H5R_ref_t is defined in H5Rpublic.h as:

typedef struct {
union {
uint8_t __data[H5R_REF_BUF_SIZE];
int64_t align;
} u;

H5Rdestroy() should be used to release the resource from the reference.

Since
1.12.0

◆ H5Rcreate_region()

herr_t H5Rcreate_region ( hid_t  loc_id,
const char *  name,
hid_t  space_id,
hid_t  oapl_id,
H5R_ref_t ref_ptr 
)

Creates a region reference.


Parameters
[in]loc_idLocation identifier. The identifier may be that of a file, group, dataset, named datatype, or attribute.
[in]nameName of object
[in]space_idDataspace identifier
[in]oapl_idObject access property list identifier
[out]ref_ptrPointer to reference
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

H5Rcreate_region() creates the reference, ref_ptr, pointing to the region represented by space_id within the object named name located at loc_id.

The parameters loc_id and name are used to locate the object. The parameter space_id identifies the dataset region that a dataset region reference points to.

The parameter oapl_id is an object access property list identifier for the referenced object. The access property list must be of the same type as the object being referenced, that is a dataset property list in this case.

H5R_ref_t is defined in H5Rpublic.h as:

typedef struct {
union {
uint8_t __data[H5R_REF_BUF_SIZE];
int64_t align;
} u;

H5Rdestroy() should be used to release the resource from the reference.

Since
1.12.0

◆ H5Rdereference1()

hid_t H5Rdereference1 ( hid_t  obj_id,
H5R_type_t  ref_type,
const void *  ref 
)

Opens the HDF5 object referenced.


Parameters
[in]obj_idObject identifier
[in]ref_typeThe reference type of ref
[in]refReference to open
Returns
Returns identifier of referenced object if successful; otherwise returns a negative value.
Deprecated:
This function has been renamed from H5Rdereference() and is deprecated in favor of the macro H5Rdereference() or the function H5Rdereference2().

Given a reference, ref, to an object or a region in an object, H5Rdereference1() opens that object and returns an identifier.

The parameter obj_id must be a valid identifier for an object in the HDF5 file containing the referenced object, including the file identifier.

The parameter ref_type specifies the reference type of the reference ref. ref_type may contain either of the following values:

The object opened with this function should be closed when it is no longer needed so that resource leaks will not develop. Use the appropriate close function, such as H5Oclose() or H5Dclose() for datasets.

Version
1.10.0 Function H5Rdereference() renamed to H5Rdereference1() and deprecated in this release.
Since
1.0.0

◆ H5Rdereference2()

hid_t H5Rdereference2 ( hid_t  obj_id,
hid_t  oapl_id,
H5R_type_t  ref_type,
const void *  ref 
)

Opens the HDF5 object referenced.


Parameters
[in]obj_idObject identifier
[in]oapl_idObject access property list identifier
[in]ref_typeThe reference type of ref
[in]refReference to open
Returns
Returns identifier of referenced object if successful; otherwise returns a negative value.

Given a reference, ref, to an object or a region in an object, H5Rdereference2() opens that object and returns an identifier.

The parameter obj_id must be a valid identifier for the HDF5 file containing the referenced object or for any object in that HDF5 file.

The parameter oapl_id is an object access property list identifier for the referenced object. The access property list must be of the same type as the object being referenced, that is a group, dataset, or datatype property list.

The parameter ref_type specifies the reference type of the reference ref. ref_type may contain either of the following values:

The object opened with this function should be closed when it is no longer needed so that resource leaks will not develop. Use the appropriate close function, such as H5Oclose() or H5Dclose() for datasets.

Since
1.10.0

◆ H5Rdestroy()

herr_t H5Rdestroy ( H5R_ref_t ref_ptr)

Closes a reference.


Parameters
[in]ref_ptrPointer to reference
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

Given a reference, ref_ptr, to an object, region or attribute attached to an object, H5Rdestroy() releases allocated resources from a previous create call.

H5R_ref_t is defined in H5Rpublic.h as:

typedef struct {
union {
uint8_t __data[H5R_REF_BUF_SIZE];
int64_t align;
} u;
Since
1.12.0

◆ H5Requal()

htri_t H5Requal ( const H5R_ref_t ref1_ptr,
const H5R_ref_t ref2_ptr 
)

Determines whether two references are equal.


Parameters
[in]ref1_ptrPointer to reference to compare
[in]ref2_ptrPointer to reference to compare
Returns
Returns a positive value if the references are equal. Returns 0 if the references are not equal. Returns a negative value when the function fails.

H5Requal() determines whether two references point to the same object, region or attribute.

H5R_ref_t is defined in H5Rpublic.h as:

typedef struct {
union {
uint8_t __data[H5R_REF_BUF_SIZE];
int64_t align;
} u;
Since
1.12.0

◆ H5Rget_attr_name()

ssize_t H5Rget_attr_name ( const H5R_ref_t ref_ptr,
char *  name,
size_t  size 
)

Retrieves the attribute name for a referenced object.


Parameters
[in]ref_ptrPointer to reference to query
[in,out]nameBuffer to place the attribute name of the reference
[in]sizeSize of the name buffer
Returns
Returns the length of the name if successful, otherwise, a negative value.

H5Rget_attr_name() retrieves the attribute name for the attribute reference pointed to by ref_ptr.

Up to size characters of the name are returned in name; additional characters, if any, are not returned to the user application. If the length of the name, which determines the required value of size, is unknown, a preliminary H5Rget_attr_name() call can be made. The return value of this call will be the size of the attribute name. That value can then be passed in for size in the second call to H5Rget_attr_name(), which will retrieve the actual name.

Since
1.12.0

◆ H5Rget_file_name()

ssize_t H5Rget_file_name ( const H5R_ref_t ref_ptr,
char *  name,
size_t  size 
)

Retrieves the file name for a referenced object.


Parameters
[in]ref_ptrPointer to reference to query
[in,out]nameBuffer to place the file name of the reference
[in]sizeSize of the name buffer
Returns
Returns the length of the name if successful, otherwise, a negative value.

H5Rget_file_name() retrieves the file name for the object, region or attribute reference pointed to by ref_ptr.

Up to size characters of the name are returned in name; additional characters, if any, are not returned to the user application. If the length of the name, which determines the required value of size, is unknown, a preliminary H5Rget_file_name() call can be made. The return value of this call will be the size of the file name. That value can then be passed in for size in the second call to H5Rget_file_name(), which will retrieve the actual name.

Since
1.12.0

◆ H5Rget_name()

ssize_t H5Rget_name ( hid_t  loc_id,
H5R_type_t  ref_type,
const void *  ref,
char *  name,
size_t  size 
)

Retrieves a name for a referenced object.


Parameters
[in]loc_idIdentifier for the file containing the reference or for any object in that file
[in]ref_typeType of reference
[in]refAn object or dataset region reference
[out]nameA buffer to place the name of the referenced object or dataset region. If NULL, then this call will return the size in bytes of the name.
[in]sizeThe size of the name buffer. When the size is passed in, the NULL terminator needs to be included.
Returns
Returns the length of the name if successful, returning 0 (zero) if no name is associated with the identifier. Otherwise returns a negative value.

H5Rget_name() retrieves a name for the object identified by ref.
loc_id is used to identify the file containing the reference. It can be the file identifier for the file containing the reference or an identifier for any object in that file.

H5R_type_t is the reference type of ref. Valid values include the following:

ref is the reference for which the target object's name is sought.

If ref is an object reference, name will be returned with a name for the referenced object. If ref is a dataset region reference, name will contain a name for the object containing the referenced region.

Up to size characters of the name are returned in name; additional characters, if any, are not returned to the user application.

If the length of the name, which determines the required value of size, is unknown, a preliminary H5Rget_name() call can be made. The return value of this call will be the size of the object name. That value can then be assigned to size for a second H5Rget_name() call, which will retrieve the actual name.

If there is no name associated with the object identifier or if the name is NULL, H5Rget_name() returns the size of the name buffer (the size does not include the NULL terminator).

Note that an object in an HDF5 file may have multiple paths if there are multiple links pointing to it. This function may return any one of these paths.

Since
1.8.0

◆ H5Rget_obj_name()

ssize_t H5Rget_obj_name ( H5R_ref_t ref_ptr,
hid_t  rapl_id,
char *  name,
size_t  size 
)

Retrieves the object name for a referenced object.


Parameters
[in]ref_ptrPointer to reference to query
[in]rapl_idReference access property list identifier
[in,out]nameBuffer to place the file name of the reference
[in]sizeSize of the name buffer
Returns
Returns the length of the name if successful, returning 0 (zero) if no name is associated with the identifier. Otherwise returns a negative value.

H5Rget_obj_name() retrieves the object name for the object, region or attribute reference pointed to by ref_ptr.

The parameter rapl_id is a reference access property list identifier for the reference. The access property list can be used to access external files that the reference points to (through a file access property list).

Up to size characters of the name are returned in name; additional characters, if any, are not returned to the user application. If the length of the name, which determines the required value of size, is unknown, a preliminary call to H5Rget_obj_name() call can be made. The return value of this call will be the size of the object name. That value can then be passed in for size in the second call to H5Rget_obj_name(), which will retrieve the actual name. If there is no name associated with the object identifier or if the name is NULL, H5Rget_obj_name() returns the size of the name buffer (the size does not include the \0 terminator).

If ref_ptr is an object reference, name will be returned with a name for the referenced object. If ref_ptr is a dataset region reference, name will contain a name for the object containing the referenced region. If ref_ptr is an attribute reference, name will contain a name for the object the attribute is attached to. Note that an object in an HDF5 file may have multiple paths if there are multiple links pointing to it. This function may return any one of these paths.

Since
1.12.0

◆ H5Rget_obj_type1()

H5G_obj_t H5Rget_obj_type1 ( hid_t  id,
H5R_type_t  ref_type,
const void *  ref 
)

Retrieves the type of object that an object reference points to.


Parameters
[in]idThe dataset containing the reference object or the group containing that dataset
[in]ref_typeType of reference to query
[in]refReference to query
Returns
Returns a valid object type if successful; otherwise returns a negative value (H5G_UNKNOWN).
Deprecated:
This function has been renamed from H5Rget_obj_type() and is deprecated in favor of the macro H5Rget_obj_type() or the function H5Rget_obj_type2().

Given an object reference, ref, H5Rget_obj_type1() returns the type of the referenced object.

A reference type is the type of reference, either an object reference or a dataset region reference. An object reference points to an HDF5 object, while a dataset region reference points to a defined region within a dataset.

The referenced object is the object the reference points to. The referenced object type, or the type of the referenced object, is the type of the object that the reference points to.

The location identifier, id, is the identifier for either the dataset containing the object reference or the group containing that dataset.

Valid reference types, to pass in as ref_type, include the following:

If the application does not already know the object reference type, that can be determined with three preliminary calls:

When the function completes successfully, it returns one of the following valid object type values (defined in H5Gpublic.h):

typedef enum H5G_obj_t {
H5G_UNKNOWN = -1,
H5G_obj_t
Definition H5Gpublic.h:550
@ H5G_LINK
Definition H5Gpublic.h:555
@ H5G_TYPE
Definition H5Gpublic.h:554
@ H5G_UNKNOWN
Definition H5Gpublic.h:551
@ H5G_GROUP
Definition H5Gpublic.h:552
@ H5G_RESERVED_6
Definition H5Gpublic.h:558
@ H5G_DATASET
Definition H5Gpublic.h:553
@ H5G_RESERVED_5
Definition H5Gpublic.h:557
@ H5G_UDLINK
Definition H5Gpublic.h:556
@ H5G_RESERVED_7
Definition H5Gpublic.h:559
Version
1.8.0 Function H5Rget_obj_type() renamed to H5Rget_obj_type1() and deprecated in this release.
Since
1.2.0

◆ H5Rget_obj_type2()

herr_t H5Rget_obj_type2 ( hid_t  id,
H5R_type_t  ref_type,
const void *  ref,
H5O_type_t obj_type 
)

Retrieves the type of object that an object reference points to.


Parameters
[in]idThe dataset containing the reference object or the group containing that dataset
[in]ref_typeType of reference to query
[in]refReference to query
[out]obj_typeType of referenced object
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

Given an object reference, ref, H5Rget_obj_type2() returns the type of the referenced object in obj_type.

A reference type is the type of reference, either an object reference or a dataset region reference. An object reference points to an HDF5 object while a dataset region reference points to a defined region within a dataset.

The referenced object is the object the reference points to. The referenced object type, or the type of the referenced object, is the type of the object that the reference points to.

The location identifier, id, is the identifier for either the dataset containing the object reference or the group containing that dataset.

Valid reference types, to pass in as ref_type, include the following:

If the application does not already know the object reference type, that can be determined with three preliminary calls:

When the function completes successfully, it returns one of the following valid object type values (defined in H5Opublic.h):

typedef enum H5O_type_t {
H5O_type_t
Definition H5Opublic.h:107
@ H5O_TYPE_MAP
Definition H5Opublic.h:112
@ H5O_TYPE_DATASET
Definition H5Opublic.h:110
@ H5O_TYPE_UNKNOWN
Definition H5Opublic.h:108
@ H5O_TYPE_NAMED_DATATYPE
Definition H5Opublic.h:111
@ H5O_TYPE_GROUP
Definition H5Opublic.h:109
@ H5O_TYPE_NTYPES
Definition H5Opublic.h:113
Since
1.8.0

◆ H5Rget_obj_type3()

herr_t H5Rget_obj_type3 ( H5R_ref_t ref_ptr,
hid_t  rapl_id,
H5O_type_t obj_type 
)

Retrieves the type of object that an object reference points to.


Parameters
[in]ref_ptrPointer to reference to query
[in]rapl_idReference access property list identifier
[out]obj_typeType of referenced object
Returns
Returns a non-negative value if successful; otherwise, returns a negative value.

Given a reference, ref_ptr, H5Rget_obj_type3() retrieves the type of the referenced object in obj_type.

The parameter rapl id is a reference access property list identifier for the reference. The access property list can be used to access external files that the reference points to (through a file access property list).

Upon success, the function returns in obj_type the type of the object that the reference points to. Valid values for this referenced object type are as followed (defined in H5Opublic.h):

Since
1.12.0

◆ H5Rget_region()

hid_t H5Rget_region ( hid_t  dataset,
H5R_type_t  ref_type,
const void *  ref 
)

Sets up a dataspace and selection as specified by a region reference.


Parameters
[in]datasetFile identifier or identifier for any object in the file containing the referenced region
[in]ref_typeReference type of ref, which must be H5R_DATASET_REGION
[in]refRegion reference to open
Returns
Returns a valid dataspace identifier if successful; otherwise returns a negative value.

H5Rget_region() creates a copy of the dataspace of the dataset pointed to by a region reference, ref, and defines a selection matching the selection pointed to by ref within the dataspace copy.

dataset is used to identify the file containing the referenced region; it can be a file identifier or an identifier for any object in the file.

The parameter ref_type specifies the reference type of ref and must contain the value H5R_DATASET_REGION.

Use H5Sclose() to release the dataspace identifier returned by this function when the identifier is no longer needed.

Since
1.0.0

◆ H5Rget_type()

H5R_type_t H5Rget_type ( const H5R_ref_t ref_ptr)

Retrieves the type of a reference.


Parameters
[in]ref_ptrPointer to reference
Returns
Returns a valid reference type if successful; otherwise returns H5R_BADTYPE .

Given a reference, ref_ptr, H5Rget_type() returns the type of the reference.

Valid returned reference types are:

Note that H5R_OBJECT1 and H5R_DATASET_REGION1 can never be associated with an H5R_ref_t reference and can, therefore, never be returned through that function.

H5R_ref_t is defined in H5Rpublic.h as:

typedef struct {
union {
uint8_t __data[H5R_REF_BUF_SIZE];
int64_t align;
} u;
Since
1.12.0

◆ H5Ropen_attr()

hid_t H5Ropen_attr ( H5R_ref_t ref_ptr,
hid_t  rapl_id,
hid_t  aapl_id 
)

Opens the HDF5 attribute referenced.


Parameters
[in]ref_ptrPointer to reference to open
[in]rapl_idReference access property list identifier
[in]aapl_idAttribute access property list identifier
Returns
Returns a attribute identifier if successful; otherwise returns H5I_INVALID_HID.

Given a reference, ref_ptr, to an attribute attached to an object, H5Ropen_attr() opens the attribute attached to that object and returns an identifier.

The parameter rapl id is a reference access property list identifier for the reference. The access property list can be used to access external files that the reference points to (through a file access property list).

The parameter aapl_id is an attribute access property list identifier for the referenced attribute.

The attribute opened with this function should be closed with H5Aclose() when it is no longer needed.

Since
1.12.0

◆ H5Ropen_object()

hid_t H5Ropen_object ( H5R_ref_t ref_ptr,
hid_t  rapl_id,
hid_t  oapl_id 
)

Opens the HDF5 object referenced.


Parameters
[in]ref_ptrPointer to reference to open
[in]rapl_idReference access property list identifier
[in]oapl_idObject access property list identifier
Returns
Returns a object identifier if successful; otherwise returns H5I_INVALID_HID.

Given a reference, ref_ptr, to an object, a region in an object, or an attribute attached to an object, H5Ropen_object() opens that object and returns an identifier.

The parameter oapl_id is an object access property list identifier for the referenced object. The access property list must be of the same type as the object being referenced, that is a group or dataset property list.

H5R_ref_t is defined in H5Rpublic.h as:

typedef struct {
union {
uint8_t __data[H5R_REF_BUF_SIZE];
int64_t align;
} u;

The object opened with this function should be closed when it is no longer needed so that resource leaks will not develop. Use the appropriate close function, such as H5Oclose() or H5Dclose() for datasets.

Since
1.12.0

◆ H5Ropen_region()

hid_t H5Ropen_region ( H5R_ref_t ref_ptr,
hid_t  rapl_id,
hid_t  oapl_id 
)

Sets up a dataspace and selection as specified by a region reference.


Parameters
[in]ref_ptrPointer to reference to open
[in]rapl_idReference access property list identifier
[in]oapl_idObject access property list identifier
Returns
Returns a dataspace identifier if successful; otherwise returns H5I_INVALID_HID.

H5Ropen_region() creates a copy of the dataspace of the dataset pointed to by a region reference, ref_ptr, and defines a selection matching the selection pointed to by ref_ptr within the dataspace copy.

The parameter rapl id is a reference access property list identifier for the reference. The access property list can be used to access external files that the reference points to (through a file access property list).

The parameter oapl id is an object access property list identifier for the referenced object. The access property list must be of the same type as the object being referenced, that is a dataset property list in that case.

Use H5Sclose() to release the dataspace identifier returned by this function when the identifier is no longer needed.

Since
1.12.0