_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
Waiting in a loop until the screen exists to add the title. The _LIMIT prevents the loop from using all CPU time while waiting.
SCREEN 12
DO: _LIMIT 10: LOOP UNTIL _SCREENEXISTS
_TITLE "My Title"


See also



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