SET(SCREEN_UPDATE)

This built-in activates/deactivates screen updating. When a screen update is enabled (ON), the update is immediate. All the updates that had been set when update was off will be done as soon as it is enabled. When disabled (OFF), the screen is frozen until update is turned on again. Update attempts when screen updating is inactive will have no effect or will signal an error. An ON or OFF value is returned when setting screen update to signal whether or not it was active before this execution. Screen updating is global. All windows must simultaneously have screen update ON or OFF.

Syntax:

previous_setting := SET(SCREEN_UPDATE, {ON | OFF} )

Example:

The following turns screen updating OFF until the loop_process procedure is complete.

SET(screen_update, OFF);

loop_process;

SET(screen_update, ON);

Errors:

TPU$_BADKEY Invalid keyword.

TPU$_UNKKEYWORD Second parameter must be ON or OFF.

Related Builtins: