_SCREENEXISTS

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The _SCREENEXISTS function returns true (-1) once a screen has been created.


Syntax

screenReady%% = _SCREENEXISTS


Description

  • Function returns true (-1) once a program screen is available to use or change.
  • Can be used to avoid program errors because a screen was not ready for input or alterations.
    • Use before _TITLE, _SCREENMOVE and other functions that require the output window to have been created.


Examples

Example: The loop busy-waits until the screen exists to add the title.

SCREEN 12 DO: LOOP UNTIL _SCREENEXISTS _TITLE "My Title"


See also



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