Topic       : The GFA-Basic Compendium
Author      : GFA Systemtechnik GmbH
Version     : GFABasic.HYP v2.98 (12/31/2023)
Subject     : Documentation/Programming
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Index Size  : 28056
HCP-Version : 3
Compiled on : Atari
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@hostname   : CAB     
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View Ref-FileV_CLRWK()
V_UPDWK()

The function V_CLRWK() (Clear Workstation) clears the output buffer. For
example, the screen or printer buffer is cleared.

For output of graphics to a printer, all commands are collected in a buffer.
The function V_UPDWK() (Update Workstation) sends these buffered graphic
instructions to the attached device. Unlike printer graphics, for example, all
graphic instructions sent to the screen are implemented immediately.

Example:

    ' If GDOS is resident
    RESERVE 25600       !Reserve sufficient storage memory
    handle&=V_OPNWK(21) !Determine identification for output device
    '
    IF handle&=0
      ALERT 3,"Installation error!",1,"Cancel",r%
      END
    ENDIF
    '
    x_res&=INTOUT(0) !Determine x- and y-resolution
    y_res&=INTOUT(1) !of the attached device
    '
    V~H=handle& !Sets the internal VDI handle to printer identification
    ~V_CLRWK() !Clear buffer
    '
    CLIP 0,0,x_res&,y_res&
    BOX 0,0,x_res&,y_res&
    LINE 0,0,x_res&,y_res&
    LINE 0,y_res&,x_res&,0
    '
    ~V_UPDWK() !Carry out Graphic commands
    ~V_CLSWK()
    '
    RESERVE    !Return memory to GFA Basic

--> Sends a rectangle with a diagonal line through it to an attached printer,
    if GDOS is resident.

Memo: Neither of these return any useful result. The VDI documentation
      lists them as not returning anything. They seem to return INTOUT(0) but
      it's useless.

v_clrwk()+, v_updwk()+