def getDiskPoolNames(rh):
    """
    Obtain the list of disk pools known to the directory manager.

    Input:
       Request Handle with the following properties:
          function    - 'GETHOST'
          subfunction - 'DISKPOOLNAMES'

    Output:
       Request Handle updated with the results.
       Return code - 0: ok, non-zero: error
    """

    rh.printSysLog("Enter getHost.getDiskPoolNames")

    parms = ["-q", "1", "-e", "3", "-T", "dummy"]
    results = invokeSMCLI(rh, "Image_Volume_Space_Query_DM", parms)
    if results['overallRC'] == 0:
        for line in results['response'].splitlines():
            poolName = line.partition(' ')[0]
            rh.printLn("N", poolName)
    else:
        # SMAPI API failed.
        rh.printLn("ES", results['response'])
        rh.updateResults(results)    # Use results from invokeSMCLI

    rh.printSysLog("Exit getHost.getDiskPoolNames, rc: " +
        str(rh.results['overallRC']))
    return rh.results['overallRC']