SWPUSEXMS
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  Function : Enable or disable use of XMS memory by the swap system.

  Syntax   : lValue = SWPUSEXMS(lFlag)

  Return   : The previous setting

  Default  : Enabled

  This function enables or disables the use of XMS memory for swap image
  storage.  The return value is the previous setting.  If XMS use is
  enabled, the parent image can be saved (and restored) much more quickly
  that if it were written to disk.

  Note that when both XMS and EMS memory are available, the swap system
  will use XMS first.