If an error condition occurs, this routine returns an integer
    value indicating the type of error. Possible return values are as
    follows:

    Return      Description

    0           Successful completion.
    [EINVAL]    The value specified by key is not a valid key, or the
                length in characters of name exceeds 31.
    [ENOMEM]    Insufficient memory exists to create a copy of the
                object name string.