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JAVA

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C

 

Link

H5L_GET_INFO

Returns information about a link

Procedure:

H5L_GET_INFO(link_loc_id, link_name, link_buff, lapl_id)

Signature:

herr_t H5Lget_info( hid_t link_loc_id, const char *link_name, H5L_info_t *link_buff, hid_t lapl_id )

SUBROUTINE h5lget_info_f(link_loc_id, link_name, &
     cset, corder, f_corder_valid, link_type, address, val_size, &
     hdferr, lapl_id)
  IMPLICIT NONE
  INTEGER(HID_T), INTENT(IN) :: link_loc_id 
                        ! File or group identifier.
  CHARACTER(LEN=*), INTENT(IN) :: link_name 
                        ! Name of the link for which information is being sought.
  INTEGER, INTENT(OUT) :: cset 
                        ! Indicates the character set used for the link’s name. 
  INTEGER, INTENT(OUT) :: corder 
                        ! Specifies the link’s creation order position.
  LOGICAL, INTENT(OUT) :: f_corder_valid 
                        ! Indicates whether the value in corder is valid.
  INTEGER, INTENT(OUT) :: link_type 
                        ! Specifies the link class:
                        !  H5L_TYPE_HARD_F      - Hard link
                        !  H5L_TYPE_SOFT_F      - Soft link
                        !  H5L_TYPE_EXTERNAL_F  - External link
                        !  H5L_TYPE_ERROR_F     - Error
  INTEGER(HADDR_T), INTENT(OUT) :: address  
                        ! If the link is a hard link, address specifies the file
                        ! address that the link points to
  INTEGER(SIZE_T), INTENT(OUT) :: val_size 
                        ! If the link is a symbolic link, val_size will be the 
                        ! length of the link value, i.e. the length of the name 
                        ! of the pointed-to object with a null terminator. 

  INTEGER, INTENT(OUT) :: hdferr 
                        ! Error code:
                        ! 0 on success and -1 on failure
  INTEGER(HID_T), OPTIONAL, INTENT(IN) :: lapl_id  
                        ! Link access property list
END SUBROUTINE h5lget_info_f

Parameters:
hid_t link_loc_idIN: Location identifier; may be a file, group, dataset, named datatype or attribute identifier
const char *link_nameIN: Name of the link for which information is being sought
H5L_info_t *link_buff    OUT: Buffer in which link information is returned
hid_t lapl_idIN: Link access property list identifier

Description:

H5L_GET_INFO returns information about the specified link through the link_buff argument.

The location identifier, link_loc_id, specifies the location of the link. A link name, link_name, interpreted relative to link_loc_id, specifies the link being queried.

lapl_id is the link access property list associated with the link link_name. In the general case, when default link access properties are acceptable, this can be passed in as H5P_DEFAULT. An example of a situation that requires a non-default link access property list is when the link is an external link; an external link may require that a link prefix be set in a link access property list (see H5P_SET_ELINK_PREFIX).

H5L_GET_INFO returns information about link_name in the data structure H5L_info_t, which is described below and defined in H5Lpublic.h. This structure is returned in the buffer link_buff.

    typedef struct {
        H5L_type_t     type;
        hbool_t        corder_valid;
        int64_t        corder;
        H5T_cset_t     cset;
        union {
            haddr_t    address;
            size_t     val_size;
        } u;
    } H5L_info_t;
        

In the above struct, type specifies the link class. Valid values include the following:

H5L_TYPE_HARDHard link
H5L_TYPE_SOFTSoft link
H5L_TYPE_EXTERNAL    External link
H5L_TYPE_ERRORError

There will be additional valid values if user-defined links have been registered.

corder specifies the link’s creation order position while corder_valid indicates whether the value in corder is valid.

If corder_valid is TRUE, the value in corder is known to be valid; if corder_valid is FALSE, the value in corder is presumed to be invalid;

corder starts at zero (0) and is incremented by one (1) as new links are created. But higher-numbered entries are not adjusted when a lower-numbered link is deleted; the deleted link’s creation order position is simply left vacant. In such situations, the value of corder for the last link created will be larger than the number of links remaining in the group.

cset specifies the character set in which the link name is encoded. Valid values include the following:

H5T_CSET_ASCIIUS ASCII
H5T_CSET_UTF8    UTF-8 Unicode encoding

This value is set with H5P_SET_CHAR_ENCODING.

address and val_size are returned for hard and symbolic links, respectively. Symbolic links include soft and external links and some user-defined links.

If the link is a hard link, address specifies the file address that the link points to.

If the link is a symbolic link, val_size will be the length of the link value, e.g., the length of the name of the pointed-to object with a null terminator.

Returns:

Returns a non-negative value if successful, with the fields of link_buff (if non-null) initialized. Otherwise returns a negative value.

Example:

Coming Soon!

History:
Release    C
1.8.0Function introduced in this release.
1.8.2Fortran subroutine added in this release.
1.8.4Fortran subroutine syntax changed in this release.
 

may be a file, group, dataset, named datatype or attribute identifier

--- Last Modified: May 08, 2018 | 11:34 AM