Creating an Group

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Creating an group

An HDF5 group is a structure containing zero or more HDF5 objects. The two primary HDF5 objects are groups and datasets. To create a group, the calling program must:

1. Obtain the location identifier where the group is to be created.
2. Create the group.
3. Close the group.

To create a group, the calling program must call H5Gcreate. To close the group, H5Gclose must be called. The close call is mandatory.

For example:

C

group_id = H5Gcreate(file_id, "/MyGroup", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
status = H5Gclose (group_id);

Fortran

CALL h5gcreate_f (loc_id, name, group_id, error)
CALL h5gclose_f (group_id, error)

Programming Example

Description

See Examples from Learning the Basics for the examples used in the Learning the Basics tutorial.

The example shows how to create and close a group. It creates a file called group.h5 in C (groupf.h5 for FORTRAN), creates a group called MyGroup in the root group, and then closes the group and file.

For details on compiling an HDF5 application: [ Compiling HDF5 Applications ]

File Contents

Shown below is the contents and the definition of the group of group.h5 (created by the C program). (The FORTRAN program creates the HDF5 file groupf.h5 and the resulting DDL shows the filename groupf.h5 in the first line.)

The Contents of group.h5.

group.h5 in DDL

HDF5 "group.h5" {
GROUP "/" {
   GROUP "MyGroup" {
   }
}
}

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