h5umount

// Create an HDF5 file
a = h5open(TMPDIR + "/test.h5", "w")

// we create a group which will be used as mount point
h5group(a, "/mnt");

// Create another file with a group and a dataset
b = h5open(TMPDIR + "/test1.h5", "w")
h5group(b, "Group_1");
h5write(b, "Group_1/Dataset_1", [1 2;3 4]);

// Mount b on a
h5mount(a, "/mnt", b)

// Now we can modify or read b like if we were in a
a.root.mnt.Group_1.Dataset_1.data
h5write(a.root.mnt.Group_1, "Dataset_1", [10 11;12 13])

// We can now unmount and remove the mount point
h5umount(a, "/mnt")
h5rm(a, "/mnt")

// We close all
h5close(a, b)

// Check that the modification in b is ok
h5dump(TMPDIR + "/test1.h5", "/Group_1/Dataset_1")