AppTerminate and AppTerminate()

Strict

Graphics 800 , 600 , 0

Global x% = 0

Global term() = AppTerminate

Repeat
gameloop()
Until KeyHit(KEY_ESCAPE) Or term()

Function gameloop()
x = (X + 1) Mod 600
Cls
DrawText ( "O",x,100 )
Flip
End Function

it's a function pointer.