(LOGO.JPG) Python for OpenVMS

(go to: table of contents, index, list of vms_smg, prev: PREV, next: BEGIN_PASTEBOARD_UPDATE)


BEGIN_DISPLAY_UPDATE - Begin Batching of Display Updates

Saves, or batches, all output to a virtual display until a matching call to vms_smg.end_display_update() is encountered.

Format:

    status = vms_smg.begin_display_update (display_id)
Returns:
status
Condition code as returned from SMG$BEGIN_DISPLAY_UDPATE. Either SS$_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 batched.
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)
>>> status = vms_smg.put_chars (vtdpy1, 'BAT2', 4, 4)

Notice that no new output appears inside the display.

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

Screen layout, file: VMS_SMG_014.JPG

(picture VMS_SMG_014.JPG)

Full output is now visible.


(go to: table of contents, index, list of vms_smg, prev: PREV, next: BEGIN_PASTEBOARD_UPDATE)

10-SEP-2000 ZE.