Difference between revisions of "SCREENEXISTS"

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{{DISPLAYTITLE:_SCREENEXISTS}}
{{DISPLAYTITLE:_SCREENEXISTS}}
The [[_SCREENEXISTS]] function returns a -1 value once a screen has been created.
The [[_SCREENEXISTS]] function returns true (-1) once a screen has been created.





Revision as of 00:21, 9 September 2017

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 waits until the screen exists to add the title.

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


See also



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