XPdiskTotal()
   DiskTotal reports the total disk space in bytes
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   Function:   XPdiskTotal()

               DiskTotal reports the total disk space of a
               specified drive, in bytes. This is the complementary
               function of Clipper's DiskSpace() function.

   Syntax:     XPdiskTotal([<nDisk>]) --> nTotal

   Arguments:  <nDisk> is a number indicating a drive, 0 means
               current drive, 1=A etc.. When Ommitted, DiskTotal
               assumes current drive.

   Returns:    The Total DiskSpace in bytes, or -1 when specified
               drive was invalid.

   Usage:      /* Check for drive usage.. */
               if DiskSpace()/XPdiskTotal() < 0.05
                    XPalert('Disk Space WARNING',;
                      'There is Less than 5% of Disk Space Left!;'+;
                      'Take necessary action right away!')
               end