HDF5 Attribute Interface

Description

These functions create and manipulate attributes and information about attributes.

Usage

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H5Acreate       (h5obj, name, dtype_id, h5space)
H5Aclose        (h5attribute)
H5Adelete       (h5obj, name)
H5Aexists       (h5obj, name)
H5Aget_name     (h5attribute)
H5Aget_space    (h5attribute)
H5Aget_type     (h5attribute)
H5Aopen         (h5obj, name)
H5Aopen_by_idx  (h5obj, n, objname = ".", index_type = h5default("H5_INDEX"), order = h5default("H5_ITER"))
H5Aopen_by_name (h5obj, objname = ".", name)
H5Aread         (h5attribute, buf = NULL)
H5Awrite        (h5attribute, buf)

Arguments

h5obj

An object of class H5IdComponent representing a H5 object identifier (file, group, or dataset). See H5Fcreate, H5Fopen, H5Gcreate, H5Gopen, H5Dcreate, or H5Dopen to create an object of this kind.

name

The name of the attribute (character).

dtype_id

A character name of a datatype. See h5const("H5T") for possible datatypes. Can also be an integer representing an HDF5 datatype. Only simple datatypes are allowed for atttributes.

h5space

An object of class H5IdComponent representing a H5 dataspace. See H5Dget_space, H5Screate_simple, H5Screate to create an object of this kind.

h5attribute

An object of class H5IdComponent represnting a H5 attribute as created by H5Acreate or H5Aopen

n

Opens attribute number n in the given order and index. The first attribute is opened with n=0.

objname

The name of the object the attribute belongs to.

index_type

See h5const("H5_INDEX") for possible arguments.

order

See h5const("H5_ITER") for possible arguments.

buf

Reading and writing buffer containing the data to written/read. When using the buffer for reading, the buffer size has to fit the size of the memory space h5spaceMem. No extra memory will be allocated for the data. A pointer to the same data is returned.

Details

Interface to the HDF5 C-library libhdf5. See http://www.hdfgroup.org/HDF5/doc/RM/RM_H5A.html for further details.

Value

H5Acreate, H5Aopen, H5Aopen_by_name, H5Aopen_by_idx return an object of class H5IdComponent representing a H5 attribute identifier.

H5Aget_space returns an object of class H5IdComponent representing a H5 dataspace identifier.

H5Aread returns an array with the read data.

The other functions return the standard return value from their respective C-functions.

Author(s)

Bernd Fischer

References

http://www.hdfgroup.org/HDF5

See Also

rhdf5

Examples

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# create a file and write something
h5createFile("ex_H5A.h5")
h5write(1:15, "ex_H5A.h5","A")

# write an attribute 'unit' to 'A'
fid <- H5Fopen("ex_H5A.h5")
did <- H5Dopen(fid, "A")
sid <- H5Screate_simple(c(1,1))
tid <- H5Tcopy("H5T_C_S1")

H5Tset_size(tid, 10L)
aid <- H5Acreate(did, "unit", tid, sid)
aid
H5Awrite(aid, "liter")
H5Aclose(aid)
H5Sclose(sid)
H5Aexists(did, "unit")
H5Dclose(did)
H5Fclose(fid)
h5dump("ex_H5A.h5")

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