qb64/internal/help/_SCREENEXISTS.md

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.

Example(s)

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

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

See Also

• _FULLSCREEN
• _SCREENIMAGE
• $CONSOLE
• $RESIZE