# cf.FM_THRESHOLD

`cf.``FM_THRESHOLD`()

  The amount of memory which is kept free as a temporary work space.

  This is the chunk size (returned and set by `cf.CHUNKSIZE`) multiplied by the number of chunks of memory to be kept free (returned and set by `cf.MINNCFM`).

  See also

  `cf.CHUNKSIZE`, `cf.MINNCFM`

  Returns: | out: `float` The amount of memory in bytes.
  Examples: |

      >>> cf.FM_THRESHOLD()
      10000000000.0
      >>> old = cf.MINNCFM(2*cf.MINNCFM())
      >>> cf.FM_THRESHOLD()
      20000000000.0