(LOGO.JPG) Python for OpenVMS

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FLUSH_DISPLAY_UPDATE - Flush Display Update

Flushes any update batching to the screen and leaves the update batching in effect. See also vms_smg.end_display_update().

Format:

    status = vms_smg.flush_display_update (display_id)
Returns:
status
Condition code as returned from SMG$FLUSH_DISPLAY_UPDATE. Either SS$_NORMAL or SMG$_BATWAS_ON are returned here - all other codes produce a Python exception. (The latter code is not mentioned in the documentation of OpenVMS VAX V6.1).
Arguments:
display_id
Virtual display for which output is to be flushed.
Examples:
>>> import vms_smg
>>> import vms_smgdef

>>> # create a new DECwindows terminal using SMG
>>> status, pasteboard_id, number_of_pasteboard_rows, \
... number_of_pasteboard_columns, type_of_terminal,   \
... device_name = vms_smg.create_pasteboard           \
...   (None, vms_smgdef.SMG_M_WORKSTATION)
>>>

>>> # create virtual display 1
>>> status, vtdpy1 = vms_smg.create_virtual_display \
...         (5, 10, vms_smgdef.SMG_M_BORDER, None, None)
>>>

>>> # paste virtual display 1
>>> status = vms_smg.paste_virtual_display \
...          (vtdpy1, pasteboard_id, 3, 5, None)
>>>

>>> # write to virtual display 1
>>> status = vms_smg.put_chars (vtdpy1, 'V1', 0, 0)
>>> status = vms_smg.put_chars (vtdpy1, 'TXT', 2, 2)
>>>

Screen layout, file: VMS_SMG_006.JPG

(picture VMS_SMG_006.JPG)

>>> # begin batching of virtual display 1
>>> status = vms_smg.begin_display_update (vtdpy1)
>>>

>>> # again write to virtual display 1
>>> status = vms_smg.put_chars (vtdpy1, 'BAT1', 3, 3)
>>>

Notice that no new output appears inside the display.

>>> # Flush the output
>>> status = vms_smg.flush_display_update (vtdpy1)
>>> import vms_sys
>>> print vms_sys.getmsg (status)[0]
%SYSTEM-S-NORMAL, normal successful completion
>>>

"BAT1" is now visible.

>>> # again write to virtual display 1
>>> status = vms_smg.put_chars (vtdpy1, 'BAT2', 4, 4)
>>>

>>> # end batching of virtual display 1
>>> status = vms_smg.end_display_update (vtdpy1)
>>>

"BAT2" is now visible:

Screen layout, file: VMS_SMG_014.JPG

(picture VMS_SMG_014.JPG)

>>> # it makes no sense to flush when batching is off
>>> status = vms_smg.flush_display_update (vtdpy1)
>>>
>>> print vms_sys.getmsg (status)[0]
%SMG-S-BATWASOFF, batching was off
>>>

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10-SEP-2000 ZE.