H5O_GET_INFO

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Retrieves the metadata for an object specified by an identifier

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<pre><code class="language-c">herr_t H5Oget_info( hid_t object_id, H5O_info_t *object_info, unsigned int fields)</code></pre>

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<pre><code class="language-c">herr_t H5Oget_info( hid_t object_id, H5O_info_t *object_info )</code></pre>

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<pre><code class="language-fortran">SUBROUTINE h5oget_info_f(object_id, object_info, hdferr)

    USE, INTRINSIC :: ISO_C_BINDING
    IMPLICIT NONE
    INTEGER(HID_T)  , INTENT(IN)            :: object_id
    TYPE(h5o_info_t), INTENT(OUT), TARGET   :: object_info
    INTEGER         , INTENT(OUT)           :: hdferr</code></pre>

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Related Fortran2003 Derived Type: h5o_info_t

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<pre><code class="language-fortran">  TYPE, BIND(C) :: space_t
     INTEGER(hsize_t) :: total ! Total space for storing object header in file
     INTEGER(hsize_t) :: meta  ! Space within header for object header metadata 
                               ! information
     INTEGER(hsize_t) :: mesg  ! Space within header for actual message 
                               ! information
     INTEGER(hsize_t) :: free  ! Free space within object header
  END TYPE space_t

  TYPE, BIND(C) :: mesg_t
     INTEGER(c_int64_t) :: present ! Flags to indicate presence of message type 
                                   ! in header 
     INTEGER(c_int64_t) :: shared  ! Flags to indicate message type is shared 
                                   ! in header
  END TYPE mesg_t
  
  TYPE, BIND(C) :: hdr_t
     INTEGER :: version ! Version number of header format in file
     INTEGER :: nmesgs  ! Number of object header messages
     INTEGER :: nchunks ! Number of object header chunks
     INTEGER :: flags   ! Object header status flags
     TYPE(space_t)  :: space   
     TYPE(mesg_t)   :: mesg
  END TYPE hdr_t

  ! Extra metadata storage for obj & attributes
  TYPE, BIND(C) :: H5_ih_info_t
     INTEGER(hsize_t) :: index_size ! btree and/or list
     INTEGER(hsize_t) :: heap_size
  END TYPE H5_ih_info_t

  TYPE, BIND(C) :: meta_size_t
     TYPE(H5_ih_info_t) :: obj  ! v1/v2 B-tree & local/fractal heap for 
                                ! groups, B-tree for chunked datasets
     TYPE(H5_ih_info_t) :: attr ! v2 B-tree & heap for attributes
  ENDTYPE meta_size_t
  
  TYPE, BIND(C) :: h5o_info_t
     INTEGER(C_LONG)  :: fileno     ! File number that object is located in
     INTEGER(haddr_t) :: addr       ! Object address in file  
     INTEGER(C_INT)   :: type       ! Basic object type (group, dataset, etc.) 
     INTEGER          :: rc         ! Reference count of object

     INTEGER, DIMENSION(8) :: atime ! Access time        !    -- NOTE --
     INTEGER, DIMENSION(8) :: mtime ! Modification time  ! Returns an integer 
     INTEGER, DIMENSION(8) :: ctime ! Change time        ! array as specified 
     INTEGER, DIMENSION(8) :: btime ! Birth time         ! in Fortran intrinsic 
                                                         ! DATE_AND_TIME(VALUES)

     INTEGER(hsize_t) :: num_attrs  ! # of attributes attached to object

     TYPE(hdr_t) :: hdr

     TYPE(meta_size_t) :: meta_size
  END TYPE h5o_info_t</code></pre>

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H5O_GET_INFO is a macro that is mapped to:

Such macros are provided to facilitate application compatibility. Their use and mappings are fully described in API Compatibility Macros in HDF5; we urge you to read that document closely.

In HDF5 versions 1.12 and after, H5O_GET_INFO is mapped to H5O_GET_INFO3 and H5O_GET_INFO1 is deprecated. In version 1.10 H5O_GET_INFO is identical to H5O_GET_INFO1.

If using 1.10 (1.10.3+) and encountering performance issues, please use H5O_GET_INFO2 to limit the search to specified fields retrieved, which can help with performance.

Specific compile-time compatibility flags and the resulting mappings are as follows:

Compatibility setting H5Oget_info

No compatibility flag

H5O_GET_INFO3 (in release 1.12)

H5O_GET_INFO1 (in 1.8 or 1.10)

Emulate Release 1.12 H5O_GET_INFO3

Emulate Release 1.10/1.8 interface H5O_GET_INFO1

Note:

Note

If you are iterating through a lot of different objects to retrieve information via the H5O_GET_INFO family of routines, you may see memory building up. This can be due to memory allocation for metadata such as object headers and messages when the iterated objects are put into the metadata cache.

If the memory buildup is not desirable, you can configure a smaller cache via H5F_SET_MDC_CONFIG or set the file access property list via H5P_SET_MDC_CONFIG. A smaller sized cache will force metadata entries to be evicted from the cache, thus freeing the memory associated with the entries.

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branchId	refs/heads/1.10/master
projectKey	HDFFV
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Release	Change
1.12.0	The macro H5O_GET_INFO and the function H5O_GET_INFO3 were added, and H5O_GET_INFO1 was deprecated.
1.10.5	The macro H5O_GET_INFO was removed. The functions H5O_GET_INFO1 and H5O_GET_INFO`are identical in this release. This change was added to restore the broken API compatibility introduced in HDF5-1.10.3.`
1.10.3	The function H5O_GET_INFO was renamed H5O_GET_INFO1. The macro H5O_GET_INFO and the function H5O_GET_INFO2 were introduced in this release.
1.8.15	Added a note about the valid values for the `version` field in the H5O_hdr_info_t structure.
1.8.11	Fortran subroutine introduced in this release.
1.8.10	Added H5O_type_t structure to the Description section. Separated H5O_hdr_info_t structure from H5O_info_t in the Description section. Clarified the definition and implementation of the time fields.
1.8.0	Function introduced in this release.

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