Int 7A Fn 09  - IBM 3270 Workstation Program API - Window Services         [I]

   AH = 09h
   BX = 8020h (synchronous request)
   CX = 00FFh
   DX = ID of window service controller (WSCTRL)
   AL = service
       01h connect to WS control
       02h disconnect from WS control
       03h add a window
       04h change window's position on screen
       05h change window's size
       06h change window's color
       07h change window's position in the presentation space
       08h hide/unhide toggle
       09h enlarge/reduce toggle
       0Ah change screen background color
       0Bh get window's position on screen
       0Ch get window's size
       0Dh get window's color
       0Eh get window's position in the presentation space
       0Fh determine whether hidden
       10h determine whether enlarged
       11h get background color
       12h get window names
       13h delete all windows from profile
       14h pick active window
       15h redraw screen
       16h redraw window
       17h delete a window from profile
       18h get active window
       19h get active screen
       1Ah get window data
       1Bh change window data
       1Ch select active screen
   ES:DI -> control block

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